JP5712416B2 - Frame transfer apparatus and network system - Google Patents

Description

  The present invention relates to the field of networks. Specifically, the present invention relates to a frame transfer technique.

  In order to increase the efficiency of the information system against the background of the expansion and complexity of the information system and the widening of the network, the information system is integrated into the data center, and a plurality of logical systems on one physical device Virtualization technology for operating devices (virtual machines) is advancing.

  The virtual machine communicates via a virtual network configured in a server that is a device that operates the virtual machine. The virtual network has a configuration in which an external network and a virtual machine are connected to each other via Edge Relay (ER) which is a virtual network device.

  Until now, Virtual Edge Bridge (VEB) has been widely used as ER. VEB is an ER that performs switching processing of the data link layer in the OSI reference model. Since VEB is a virtualized switch of a network device, it is also called a virtual switch.

  Usually, VEB is implemented by software on a server on which a virtual machine operates. Therefore, there has been a problem that the processing load of the CPU increases when processing using VEB, in particular, advanced switching processing such as access control is executed. Further, since VEB has a different management method from network devices outside the server, it has to be managed separately from the network devices outside the server, which increases the management and operation costs.

  An ER called Virtual Edge Port Aggregator (VEPA) has been proposed for the above-mentioned problems that VEB has. VEPA does not directly execute the switching process by itself, but directly transfers the switching target frame received from the virtual machine to an external network device (external switch) connected to the server.

  The external switch performs a switching process on the received frame, and transfers a frame that needs to be transmitted to the virtual machine connected to the VEPA to the VEPA as a result of the process. VEPA transfers the frame received from the external switch to the destination virtual machine.

  When VEPA is used, the switching process for the virtual machine frame is executed by the external switch, so that the problem in the case of using VEB can be solved. However, when VEPA is used, since the external switch executes the switching process, in the communication between virtual machines operating on the same server, the bandwidth used between the server and the external switch increases and the latency increases compared to VEB. There is a problem.

  As described above, VEB and VEPA are both ER, but the devices (positions) for executing the switching process are different. Since VEB and VEPA each have advantages and disadvantages related to a device (switching position) that performs switching processing, it is desirable to switch between VEB and VEPA according to communication in the virtual network.

  In general, the load on the server, the content of communication, and the amount of communication change from moment to moment, so the nature of the network required for communication such as computer resources, latency, and bandwidth that can be used by the virtual machine changes dynamically. For this reason, it is necessary to dynamically change a device (switching position) that performs the switching process by switching between VEB and VEPA.

  In addition, since the stop of communication greatly affects the server and the virtual machine operating on the server, the stop of the communication accompanying the change of the position of the dynamic switching process must be avoided. That is, switching between VEB and VEPA needs to be performed dynamically and with communication maintained. In addition, managing ERs such as VEB and VEPA using different methods for each server and external switch increases management and operational costs. Therefore, ER management for changing the device (location) that performs switching processing conforms to the standard. It is desirable that the management method be used.

  There are Patent Document 1 and Non-Patent Document 1 as background technologies related to VEB and VEPA, and switching between them.

  Patent Document 1 describes that a dynamic switching module determines whether to switch the traffic locally at the AP or to pass the traffic upstream, and the traffic is sent according to the determination. Yes.

  In Non-Patent Document 1, as a standard for Edge Virtual Bridging (EVB), requirements of ER (VEB and VEPA) itself and EVB Bridge (external switch) communicating with ER, notification of available functions and common use are used. An EVB TLV, which is information exchanged between the ER and EVB Bridge to determine a function, a management object of an EVB station (server) including the ER, and the like are defined.

Special table 2009-540678 gazette

IEEE P802.1Qbg / D1.6 Virtual Bridged Local Area Networks-Amendment: Edge Virtual Bridging

  In Patent Document 1, although it is not an invention related to virtualization, as processing at an access point (AP) of a wireless station, an operation corresponding to VEPA in which a wireless switch (corresponding to an external switch) performs switching processing, and AP ( (Corresponding to ER) is switched to an operation corresponding to VEB for executing a switching process.

  However, Patent Document 1 discloses an example of a trigger for switching the operation described above, but does not disclose a configuration for maintaining communication when switching the operation. Simply, when switching between VEB and VEPA, the external switch assumes that the ER is operating as a VEB, while the ER operates as a VEPA, etc. As a result, there is a possibility that a communication failure occurs such as transmission of a frame as a unit of communication and a change of order, and communication cannot be maintained.

  Furthermore, in Patent Document 1, there is no disclosure about what method (protocol) is used to manage the switching of operations corresponding to VEB and VEPA, so a management method based on the standard cannot be applied.

  On the other hand, Non-Patent Document 1 discloses management information and information handling (corresponding to a protocol) for switching between VEB and VEPA, but does not disclose a configuration for maintaining communication when switching between VEB and VEPA. Not done.

  Therefore, the conventional technique has a problem that the switching position cannot be changed while maintaining communication dynamically.

A typical example of the present invention is as follows. That is, a frame transfer apparatus that includes an arithmetic processing device, a storage device connected to the arithmetic processing device, and a network interface including one or more ports and is operable in a plurality of transfer modes, the plurality of transfer The modes include a first transfer mode, a second transfer mode, and a third transfer mode. The frame transfer apparatus includes a receiving unit that receives the frame, a transmitting unit that transmits the frame, and the frame. Mode information indicating a transfer mode of the frame transfer device, a port determination unit that determines a port to transmit, a frame analysis unit that analyzes the received frame, a learning unit that accumulates results analyzed by the frame analysis unit, A state management unit that controls the frame transfer apparatus by switching the transfer mode based on the mode information; And in the first transfer mode, the transfer process of the first frame is executed based on the analysis result of the first frame received from the port, and in the second transfer mode, the other When the second frame is received from the port to which the frame transfer apparatus is connected, the second frame is transferred based on the analysis result of the second frame, and the other frame transfer is performed. When the third frame is received from a port to which a device other than the device is connected, the third frame is transferred to the other frame transfer device. In the third transfer mode, the other frame transfer is performed. apparatus receives the fourth frame from the connected port, and, if the result of the analysis corresponding to the fourth frame are stored discards the fourth frame, the other off If the fourth frame is received from the port to which the frame transfer device is connected and the result of analysis corresponding to the fourth frame is not accumulated, the result of analysis of the fourth frame The fourth frame is transferred, and when the fifth frame is received from a port connected to a device other than the other frame transfer device , the fifth frame is analyzed. based on the results, and executes the transfer processing of the fifth frame.

  According to one aspect of the present invention, by providing the third transfer mode, the transfer mode can be dynamically switched while maintaining communication. Furthermore, the transfer mode can be switched by a method compliant with the standard. Therefore, it becomes possible to flexibly change the switching position in the frame transfer according to a predetermined opportunity, and it becomes possible to reduce the management cost and the operation cost, the processing load and the communication band, and the latency.

It is a block diagram explaining the computer system structure in the 1st Embodiment of this invention. It is a block diagram explaining the logical structure of the computer system in the 1st Embodiment of this invention. It is a block diagram which shows the software structure of Edge Relay and the bridge | bridging apparatus in the 1st Embodiment of this invention. It is explanatory drawing which shows an example of the transfer port management table | surface in the 1st Embodiment of this invention. It is explanatory drawing which shows the structure of EVB TLV in the 1st Embodiment of this invention. It is explanatory drawing which shows the mode and state transition in EdgeRelay of the 1st Embodiment of this invention. It is explanatory drawing which shows the mode and state transition in the port of the bridge | bridging apparatus of the 1st Embodiment of this invention. It is a flowchart explaining the process which EdgeRelay performs in the 1st Embodiment of this invention. It is a flowchart explaining the process which EdgeRelay performs in the 1st Embodiment of this invention. It is a flowchart explaining the frame transfer process in Edge Relay of the 1st Embodiment of this invention. It is a flowchart explaining the state transition process in Edge Relay of embodiment of this invention. It is a flowchart explaining the state transition process in Edge Relay of embodiment of this invention. It is a flowchart explaining the state transition process in Edge Relay of embodiment of this invention. It is a flowchart explaining the state transition process in Edge Relay of embodiment of this invention. It is a flowchart explaining the state transition process in Edge Relay of embodiment of this invention. It is a flowchart explaining the state transition process in Edge Relay of embodiment of this invention. It is a flowchart explaining the process which the bridge | bridging apparatus in the 1st Embodiment of this invention performs. It is a flowchart explaining the process which the bridge | bridging apparatus in the 1st Embodiment of this invention performs. It is a flowchart showing the port state transition process in the bridge device of the 1st Embodiment of this invention. It is a flowchart showing the port state transition process in the bridge device of the 1st Embodiment of this invention. It is a flowchart showing the port state transition process in the bridge device of the 1st Embodiment of this invention. It is a flowchart showing the port state transition process in the bridge device of the 1st Embodiment of this invention. It is a block diagram explaining the logical structure of the computer system in the 2nd Embodiment of this invention.

  The best mode for carrying out the present invention will be described below with reference to the drawings. The outline is a sentence supplementing other explanations, and is described with priority given to ease of understanding over accuracy and completeness.

[First Embodiment]
(System and hardware configuration)
FIG. 1 is a block diagram illustrating a computer system configuration according to the first embodiment of this invention.

  As shown in FIG. 1, the computer system includes a bridge device 101, a server device 102-1, a server device 102-2, and a node device 104. The server apparatus 102-1 is connected to the bridge apparatus 101 via the cable 105-1, the server apparatus 102-2 is connected to the bridge apparatus 101 via the cable 105-2, and the node apparatus 104 is connected to the cable 105-3. Is connected to the bridge device 101 via

  Hereinafter, when the server apparatus 102-1 and the server apparatus 102-2 are not distinguished, they are described as the server apparatus 102. Moreover, when not distinguishing the cable 105-1, the cable 105-2, and the cable 105-3, it describes as the cable 105. FIG.

  In the computer system according to the present embodiment, the bridge device 101, the server device 102-1, the server device 102-2, and the node device 104 realize communication using Ethernet (registered trademark, the same applies hereinafter).

  The bridge device 101 is a network device having a bridge function for transferring an Ethernet frame, and is also called a network switch. The Ethernet is defined in IEEE 802.3, and the bridge function is defined in IEEE 802.1D and IEEE 802.1Q.

  The cable 105 is a medium for transmitting communication by Ethernet, and may be a cable such as a metal cable or an optical fiber, or may be wireless such as a radio wave, or L2TP (Layer 2 Tunneling Protocol). Thus, it may be a logical one constructed by other communication.

  The server device 102-1, the server device 102-2, and the node device 104 are network nodes having input / output ports that comply with Ethernet. The node device 104 may be a computer similar to the server device 102, a network device including a bridge device or a router device, or a storage device connected via a network. Further, the node device 104 may be further generalized and regarded as a network called a local area network (LAN).

  In the present embodiment, the server apparatus 102 will be described as an example of the node apparatus 104. The server apparatus 102-2 is assumed to have the same configuration as the server apparatus 102-1. As shown in FIG. 1, the number of node devices 104 including the server device 102 is not limited to three, and may be any number as long as it is one or more. For example, more node devices 104 may be prepared and connected to the bridge device 101 via the cable 105 so that more node devices 104 can communicate with each other via the bridge device 101.

  In FIG. 1, a dotted line between the server device 102-1 and the server device 102-2 and between the server device 102-2 and the node device 104 is used to express that the number of the node devices 104 is arbitrary. ing. In the drawings used in the following description, the fact that the number of components is not limited is expressed using dotted lines.

  In the present embodiment, the bridge device 101, the server device 102-1, the server device 102-2, and the node device 104 are described as physically different devices, but the embodiment of the present invention is limited to this. It is not a thing.

  For example, a plurality of virtual machines are physically created in the same device using virtualization software for operating the virtual machine, and the virtual machine realizes the functions of the bridge device 101, the server device 102-1, and the node device 104. You may let them. At this time, in the virtualization using the virtualization software, the cable 105-1, the cable 105-2, and the cable 105-3 are replaced with a shared memory, an inter-memory copy, or the like.

  By using the virtual machine generated by executing the virtualization software, it becomes possible to change the flexible connection relationship and increase the utilization efficiency of the hardware.

  In the present embodiment, communication using Ethernet is described as an example. However, the present invention is not limited to Ethernet, and communication using another data link layer (Layer 2) protocol such as a wireless LAN may be used. By using other protocols, for example, it is possible to increase the bandwidth of communication and increase the reliability of communication, and the degree of freedom of wiring can be increased.

  In addition, for example, a communication path virtually configured by a VLAN tag or the like, such as S-channel defined in IEEE 802.1Qbg, is used to ensure the flexibility of the configuration, and more than the number of physical wires. A communication path may be realized.

(Hardware configuration of bridge device 101)
The hardware configuration of the bridge device 101 will be described with reference to FIG.

  The bridge device 101 includes an arithmetic processing device 108, a storage device 109, an input / output device 110, a network interface 111-1, a network interface 111-2, and a network interface 111-3, and each component is connected to each other via a shared bus 114. Is done.

  Hereinafter, when the network interface 111-1, the network interface 111-2, and the network interface 111-3 are not distinguished, they are referred to as the network interface 111.

  The network interface 111-1 is connected to the server apparatus 102-1 via the cable 105-1, the network interface 111-2 is connected to the server apparatus 102-2 via the cable 105-2, and the network interface 111-3 is connected to the cable 105-3. Are connected to the node device 104 via the network, and transmit and receive Ethernet frames between the devices.

  In FIG. 1, the number of network interfaces 111 is three according to the number of connected devices, but one or three or more may be provided. When a plurality of network interfaces 111 are provided, there may be a network interface 111 that is not connected to any device.

  The arithmetic processing unit 108 is an arithmetic processing unit represented by a central processing unit (CPU), and executes a program (software) developed on the storage unit 109. Note that the arithmetic processing unit 108 may be configured by a plurality of physical or logical CPUs.

  The storage device 109 stores a program executed by the arithmetic processing unit 108 and information necessary for executing the program. The information includes data generated during execution of the program, data read during execution of the program, and settings.

  When the arithmetic processing unit 108 executes a program stored in the storage device 109, the function of the bridge device 101 can be realized.

  The program developed on the storage device 109 is data in a format executed by the arithmetic processing unit 108, and data or a program may be included in the program, or a program may be included in the data. Well, the distinction between the two is convenient.

  The storage device 109 is, for example, a device including a storage medium capable of holding data and programs such as a memory, a hard disk, or an optical disk (a device installed at a remote location and capable of communicating via the network interface 111, the input / output device 110, etc. Included), or a combination of these.

  The programs stored in the storage device 109 include an overall control unit 120, a port control unit 121-1, a port control unit 121-2, and a port control unit 121-3. An example of data stored in the storage device 109 includes a transfer port management table 124. Below, when not distinguishing the port control part 121-1, the port control part 121-2, and the port control part 121-3, it describes as the port control part 121. FIG.

  The overall control unit 120 is a program for controlling the entire bridge device 101. The port control unit 121 is a program for controlling input / output ports provided in the network interface 111.

  Although details of these will be described later, in the following description of the bridge device 101, the writing processing such as storage, retention, storage, recording and storage of data and variables, and the reading processing such as reference and retrieval are performed by the storage device. 109 is executed.

  The programs stored in the storage device 109 are shown in order to logically distinguish the functions for controlling the bridge device 101. For example, all the programs may be executed as one program. And may be executed separately in a plurality of threads or processes. The storage device 109 may store other data generated by a program for controlling the bridge device 101.

  The input / output device 110 is a device for inputting / outputting information to / from the bridge device 101. The input / output device 110 includes devices such as a switch, a keyboard, a mouse, a microphone, a video camera, a display, and a speaker.

  Note that the input / output device 110 may be directly connected to the bridge device 101 or may be connected to the input / output device 110 via an interface connectable to the input / output device 110. Further, the input / output device 110 includes a signal cable or a device connected by communication such as serial communication performed via radio waves, infrared rays, and the like.

  The bridge device 101 can receive an instruction from the user or administrator of the bridge device 101 via the input / output device 110 and can output the result.

  The network interface 111-1, the network interface 111-2, and the network interface 111-3 include an input / output port 125-1, an input / output port 125-2, and an input / output port 125-3 for transmitting and receiving Ethernet frames, respectively. . Hereinafter, when the input / output port 125-1, the input / output port 125-2, and the input / output port 125-3 are not distinguished, they are referred to as the input / output port 125.

  The input / output port 125 is controlled by the port control unit 121 executed by the arithmetic processing unit 108, and communicates with other devices using an Ethernet frame. Hereinafter, the input / output port 125 and the port control unit 121 that controls the input / output port 125 are collectively referred to as ports.

  The shared bus 114 is for realizing communication between the components of the bridge device 101, but the present invention is not limited to the shared bus 114. As long as communication is possible between the components, they may be connected by a method other than using the shared bus 114. For example, by directly connecting each component, it is possible to optimize the connection between the elements, reduce the power consumption required for processing, and increase the processing efficiency.

(Hardware configuration of server apparatus 102)
Next, the hardware configuration of the server apparatus 102 will be described with reference to FIG.

  The server device 102 includes an arithmetic processing device 115, a storage device 116, an input / output device 117, and a network interface 118, and each component is connected to each other via a shared bus 119.

  The network interface 118 is connected to the bridge device 101 via the cable 105-1, and transmits / receives an Ethernet frame.

  In the example shown in FIG. 1, the number of the network interfaces 118 is one, but any number may be used as long as the number is one or more. In order to realize network redundancy and broadband, the server apparatus 102 includes a plurality of networks. An interface 118 may be provided.

  The arithmetic processing unit 115 is an arithmetic processing unit represented by a central processing unit (CPU), and executes a program (software) developed on the storage unit 116. Note that the arithmetic processing unit 115 may be configured by a plurality of physical or logical CPUs.

  The storage device 116 stores a program executed by the arithmetic processing unit 115 and information necessary for executing the program. The information includes data generated during execution of the program, data read during execution of the program, and settings.

  When the arithmetic processing unit 115 executes a program stored in the storage device 116, the function of the server apparatus 102 can be realized.

  The program developed on the storage device 116 is data in a format executed by the arithmetic processing unit 115, and data or a program may be included in the program, or a program may be included in the data. Well, the distinction between the two is convenient.

  The storage device 116 is, for example, a device including a storage medium capable of holding data and programs such as a memory, a hard disk, or an optical disc (a device installed at a remote location and capable of communicating via the network interface 118 or the input / output device 117). Or a combination of these.

  The programs stored in the storage device 116 include Edge Relay 128 and virtualization software 129. Examples of data stored in the storage device 116 include a virtual machine 130-1 and a virtual machine 130-2. Hereinafter, when the virtual machine 130-1 and the virtual machine 130-2 are not distinguished, they are referred to as a virtual machine 130.

  The Edge Relay 128 is a program that realizes a virtual network switch function, and provides the same configuration as that of the bridge device 101 as software. Therefore, the Edge corresponding to the programs and data such as the overall control unit 120, the port control unit 121, the transfer port management table 124, and the input / output port 125 in the bridge device 101 is included in the Edge Relay 128. Details of Edge Relay 128 will be described later.

  The virtualization software 129 is also called a hypervisor and is a program that operates a virtual computer such as the server apparatus 102. The virtualization software 129 reads data corresponding to a virtual machine such as the virtual machine 130 and operates as a virtual computer according to each data. By using the virtualization software 129, a plurality of virtual computers can be operated on the server apparatus 102.

  The virtual machine 130 is data that is the actual state of a computer that virtually operates using the virtualization software 129, and includes the state of the virtual computer, programs and data stored in the storage device 116, and the like. In the example illustrated in FIG. 1, an example in which the server apparatus 102 operates two virtual machines 130 is illustrated, but the number of virtual machines 130 is arbitrary. For example, two or more virtual machines 130 may be operated to execute more processes on the server apparatus 102 to increase the usage efficiency.

  Since the virtualization software 129 and the virtual machine 130 are general, detailed description thereof will be omitted.

  In the following description relating to the server apparatus 102, writing processing such as storage, retention, storage, recording and storage of data and variables, and reading processing such as reference and retrieval are executed for the storage device 116. Shall.

  The program stored in the storage device 116 represents the function for controlling the server device 102 in a logical manner. For example, all the programs may be executed as one program, It may be divided into a plurality of threads or processes and executed. The storage device 116 may store other data generated by a program for controlling the server device 102.

  The input / output device 117 is a device for inputting / outputting information to / from the server device 102. The input / output device 117 includes devices such as a switch, a keyboard, a mouse, a microphone, a video camera, a display, and a speaker.

  The server device 102 may be directly connected to the input / output device 117 or may be connected to the input / output device 117 via an interface connectable to the input / output device. The input / output device 117 includes a device connected by communication such as serial communication performed via a signal cable or wireless such as radio waves and infrared rays.

  The server device 102 can receive an instruction from a user or administrator of the server device 102 via the input / output device 117 and can output the result.

  The network interface 118 communicates with another device using an Ethernet frame in accordance with an instruction from the Edge Relay 128 or the virtualization software 129 executed by the arithmetic processing unit 108. The Edge Relay 128 or the virtualization software 129 communicates with other devices and components using the network interface virtually generated by the software or the network interface 118.

  The shared bus 119 is for realizing communication between the components of the server apparatus 102, but the present invention is not limited to the shared bus 119. As long as communication is possible between the components, they may be connected by a method other than using the shared bus 119. For example, by directly connecting each component, it is possible to optimize the connection between the elements, reduce the power consumption required for processing, and increase the processing efficiency.

  The node device 104 is a device that performs communication using Ethernet. For example, the node device 104 is a network device such as the bridge device 101 or a computer such as the server device 102, but does not require a configuration specific to the present invention. Description is omitted.

(Modification of system and hardware)
The configuration of the computer system illustrated in FIG. 1 is an example, and the number of components of the bridge device 101 or the server device 102 is not limited to that illustrated in FIG. For example, two input / output devices 110 and 117 may be prepared to make them redundant and share functions.

  In the present invention, some or all of the functions realized by the programs stored in the storage device 109 and the storage device 116 may be implemented as hardware. By mounting as hardware, for example, processing speed and power consumption can be reduced.

  Further, the functions of the hardware may be realized as a program using virtualization software. By realizing the functions of the hardware as a program, for example, installation space can be reduced and management can be simplified.

  In addition, the configuration of functions realized by the program is not limited to the configuration described later, and may be a configuration in which a plurality of functions are integrated or a configuration in which one function is divided into a plurality of functions. In addition, the order of processing executed by each function is not limited to the order described later. If processing dependency permits, execute in parallel at the same time, and change the execution order of the processes. Also good. For example, the processing time can be shortened by executing the processes in parallel, and the waiting time can be reduced by changing the execution order.

  FIG. 2 is a block diagram illustrating a logical configuration of the computer system according to the first embodiment of this invention.

  In the server apparatus 102, the arithmetic processing unit 115 operates as a virtual network device by executing Edge Relay 128, and the arithmetic processing unit 115 executes virtual software 129 to execute a virtual machine 130-1 that is a virtual computer. And the virtual machine 130-2 operates on the server apparatus 102.

  The Edge Relay 128, the virtual machine 130-1, and the virtual machine 130-2 are the main entities that transmit and receive Ethernet frames. In the server apparatus 102, the logical connection of the Edge Relay 128, the virtual machine 130-1, and the virtual machine 130-2 has a connection relationship as shown in FIG.

  The Edge Relay 128 is connected to the virtual machine 130-1 via the virtual cable 211-1, and is connected to the virtual machine 130-2 via the virtual cable 211-2. Hereinafter, when the virtual cable 211-1 and the virtual cable 211-2 are not distinguished, they are referred to as a virtual cable 211.

  The virtual cable 211 virtually implements the same function as that of the cable 105, and frames transmitted from the virtual machine 130 and Edge Relay 128 by a shared memory or a copy between the memories are transferred to the opposite device (the virtual machine 130 and the virtual machine 130). A virtual device such as Edge Relay 128 or a physical device such as the bridge device 101.

  The Edge Relay 128 transmits / receives a frame to / from the bridge device 101 via the cable 105-1. The cable 105-1 and the virtual cable 211 are the same in that they are connected between the components, although there is a difference between physical and logical. The virtualization software 129 controls the Edge Relay 128 so that the virtual cable 211 can be handled in the same manner as the cable 105. Note that the control in the virtualization software 129 is a general technique with names such as a virtual network interface and device virtualization, and a description thereof will be omitted.

  In the present embodiment, for example, when a frame is transmitted from the virtual machine 130-1 to the virtual machine 130-2, the transmission path of the frame differs according to the Edge Relay 128 mode described later. In other words, the frame is transmitted via a transmission path that is either a path that passes only through Edge Relay 128 or a path that passes through both Edge Relay 128 and bridge device 101.

  In the transmission path that passes through both the Edge Relay 128 and the bridge device 101, the frame is transmitted first through the Edge Relay 128, then through the bridge device 101, and then through the Edge Relay 128.

  As in the example described above, in the present embodiment, when the transmission source virtual machine 130 and the destination or delivery destination (broadcast frame or the like) virtual machine 130 are in the same server device 102, the embodiment uses the Edge Relay 128 mode. The frame transmission path changes.

  In this embodiment, since the mode of the bridge device 101 is also switched so as to be consistent with the Edge Relay 128 mode, the Edge Relay 128 mode can be switched while communication is maintained. Therefore, in this embodiment, the transmission path can be switched dynamically.

  Hereinafter, the modes of the above-described Edge Relay 128 and the bridge device 101 and the mode switching method will be described.

(Software configuration)
FIG. 3 is a block diagram illustrating software configurations of the Edge Relay 128 and the bridge device 101 according to the first embodiment of this invention.

  The Edge Relay 128 and the bridge device 101 have a difference between a virtual device and a physical device, but both operate as network devices and may have the same software configuration. To do. In FIG. 3, the bridge device 101 is mainly described as an example, and the description as the Edge Relay 128 is omitted unless there is a difference from the Edge Relay 128.

  In FIG. 3, squares represent processing blocks realized by the program to be executed. An arrow between processing blocks indicates that information or instructions and commands are transmitted in the direction of the arrow. Information or instructions and commands transmitted between processing blocks will be described later.

  The bridge device 101 includes an overall control unit 120, a port control unit 121-1, a port control unit 121-2, an input / output port 125-1 and an input / output port 125-2. Since the number of ports is arbitrary as described with reference to FIG. 1, two ports are shown in FIG. 3, and ports corresponding to the port control unit 121-3 and the input / output port 125-3 are omitted.

  In the case of Edge Relay 128, the overall control unit 120, the port control unit 121-1, the port control unit 121-2, the input / output port 125-1 and the input / output port 125-2 are included in the Edge Relay 128 as modules.

  In this embodiment, the software configuration of each port is the same, and the operation is changed depending on the port number, role, connected device, and the like. However, a software configuration suitable for each port may be used. For example, the software configuration may be changed for each port, unnecessary functions may be omitted, and the code size may be reduced. The operations of the bridge device 101 including the port and the Edge Relay 128 will be described later.

  In addition, the number of the overall control units 120 may be plural, for example, a configuration in which the same number of overall control units 120 as the ports are prepared, and each overall control unit 120 executes parallel processing for each port to shorten the processing time. But you can. In addition, a control unit that supervises a plurality of port control units 121 is added, and the control is performed by hierarchizing the processing so that the overall control unit 120 controls the control unit, thereby reducing the processing of the overall control unit 120. It may be simplified.

  The bridge device 101 transmits and receives Ethernet frames via the input / output port 125-1 and the input / output port 125-2. The port control unit 121-1 and the port control unit 121-2 control whether or not to retransmit / receive the information transmitted through the input / output port 125-1 and the input / output port 125-2 and the received information, respectively. To do.

  In addition, the port control unit 121-1 and the port control unit 121-2 move and copy information between the ports as necessary.

  The overall control unit 120 controls information transmitted / received at each port via the port control unit 121-1 and the port control unit 121-2, and changes the operation based on external input, setting, and received information. To do.

  The bridge device 101 uses each component to realize a bridge function that transmits an Ethernet frame received by a certain port from an appropriate port and relays communication of the Ethernet frame. Depending on the contents of the frame and the state of the bridge device 101, the frame may not be transmitted from the port.

  The overall control unit 120 includes a state management unit 306, a control frame processing unit 307, a control frame generation unit 308, a delivery port determination unit 309, and a port learning unit 310.

  The state management unit 306 manages the mode, state, and setting of each port and the entire apparatus. The control frame processing unit 307 extracts information by processing a control frame for notifying the state of the opposing device (the entire device or port) from the frames received from the connected opposing device.

  The control frame generation unit 308 generates a control frame that notifies the opposite device of the state of the own device (or the own port). The delivery port determination unit 309 determines a port for delivering (transmitting) the received frame based on the state of the own device (or the own port) and the contents of the destination of the received frame.

  The port learning unit 310 holds information such as the transmission source of the frame received by each port from the content of the received frame. Information held by the port learning unit 310 is used when determining a delivery port.

  The port control unit 121 includes a frame classification / information extraction unit 311, a frame storage unit 312, and a transmission / reception control unit 313.

  The frame classification / information extraction unit 311 extracts necessary information from the frame and outputs the extracted information to an appropriate component. The frame storage unit 312 holds received frames and frames to be transmitted. The transmission / reception control unit 313 controls whether frames can be transmitted and received.

  The input / output port 125 includes a frame receiving unit 314 and a frame transmitting unit 315. The frame receiving unit 314 receives a frame. The frame transmission unit 315 transmits a frame.

  In the following, it will be described how information, instructions and commands are transmitted between the components.

  First, an instruction to the bridge device 101 is made in two ways.

  One is instructed via an argument from the input / output device 110 or a program, a setting file, and a notification from another program. The instruction is input to the state management unit 306 of the overall control unit 120.

  The other is instructed using a control frame via the network interface 111. The control frame including the instruction is transmitted to the control frame processing unit 307 via the input / output port 125 and the corresponding port control unit 121, and further input to the state management unit 306.

  The state management unit 306 determines a new state based on the current state and the input instruction. The operation of the bridge device 101 is determined based on the state. The state determination method (state transition) and the operation of the bridge device 101 in each state will be described later. The contents and format of the control frame will also be described later.

  Next, a method for realizing a bridge function for transmitting an Ethernet frame received from the input / output port 125 from an appropriate port will be described.

  When a frame is transmitted to the bridge device 101, the frame is received by the frame receiving unit 314 through the network interface 111. The frame receiving unit 314 executes processing in units of frames.

  The network interface 111 performs conversion from an optical signal and an electrical signal transmitted through a medium such as the cable 105 to a frame. Note that when Edge Relay 128 receives a frame via virtual cable 211, the reception process is realized on storage device 116, so the above-described conversion process is usually not necessary. However, conversion to a frame may be executed when necessary for handling a frame, such as changing an expression (for example, endian or bit order) on the storage device 116.

  The frame reception unit 314 stores the received frame in the frame storage unit 312, and transmits an address on the storage device 116 for referring to the frame to the frame classification / information extraction unit 311.

  The information transmitted from the frame receiving unit 314 to the frame classification / information extracting unit 311 does not necessarily include the address on the storage device 116, but includes information necessary to refer to the frame. It only has to be. For example, the frame receiving unit 314 classifies the frames according to the frame contents such as the priority of the frames and stores them in different queues, and stores the queue number and the position (order, etc.) in the queue in the frame classification / information extracting unit 311. May be communicated. In this case, a frame may be distinguished for each queue, and different handling may be performed for each priority.

  The frame classification / information extraction unit 311 uses the information transmitted from the frame reception unit 314 to access the frame storage unit 312 to read the content of the frame, and classifies the frame based on the read content of the frame. . Specifically, the following processing is executed.

  When it is determined that the frame is a control frame from the destination (Destination) Mac (Media Access Control) address of the Ethernet frame, the frame classification / information extraction unit 311 transmits the frame contents to the control frame processing unit 307.

  On the other hand, when it is determined that the frame is other than the control frame, the frame classification / information extraction unit 311 determines the port number, the memory address of the frame, the destination MAC address extracted from the frame, the source MAC address, the VLAN (Virtual LAN) ID and the like are transmitted to the delivery port determination unit 309. Also, the frame classification / information extraction unit 311 transmits the port number, the source MAC address extracted from the frame, and the VLAN ID to the port learning unit 310, and whether the received frame number is the control frame. Information indicating whether or not is transmitted to the state management unit 306.

  Note that the information transmitted by the frame classification / information extraction unit 311 is not limited to the information described above. For example, the frame may be stored in a plurality of queues according to the content of the frame, the queue number may be transmitted to the delivery port determining unit 309, and the delivery port may be changed for each content of the frame. In addition, the number Forwarding ID determined from the combination of these, instead of the MAC address and VLAN ID, may be transmitted to the delivery port determining unit 309 and the port learning unit 310 to reduce the information to be transmitted. In this case, the delivery port is determined based on the Forwarding ID. Further, the configuration may be simplified by omitting the VLAN ID. Further, instead of extracting the VLAN ID from the frame, a value predetermined for each port may be used. Further, the information to be transmitted may be reduced by transmitting not the contents of the frame but the address on the storage device 116 storing the frame to the control frame processing unit 307.

  Further, as information other than the MAC address, for example, an IP (Internet Protocol) address may be used as information for identifying the destination and transmission source of the Ethernet frame.

  The control frame processing unit 307 extracts a LLDP (Link Layer Discovery Protocol) TLV (type-length-value) from the contents of the frame transmitted from the frame classification / information extraction unit 311, and transmits the TLV (type-length-value) to the state management unit 306.

  Note that the LLDP TLV is standardized as IEEE 802.1AB, and, as will be described later, in the present embodiment, only the EVB (Edge Virtual Bridging) TLV defined in IEEE 802.1Qbg is used in the LLDP TLV. However, other information such as a Chassis ID TLV may be used to help manage connected devices.

  The port learning unit 310 performs port learning only when the instruction transmitted from the state management unit 306 indicates port learning.

  In port learning, a matching entry is searched by referring to the transfer port management table 124 based on the MAC address and VLAN ID transmitted from the frame classification / information extraction unit 311. If a matching entry is found, the port number of the entry is updated. If no matching entry is found, a new entry that associates the MAC address, VLAN ID, and port number transmitted from the frame classification / information extraction unit 311 is generated in the transfer port management table 124.

  In the transfer port management table 124, the old entry is deleted. In the present invention, the function corresponding to port learning is not an essential configuration. For example, the entry search process may be accelerated by generating an entry in advance and omitting the update process.

  Note that details of port learning such as entry addition and deletion in the forwarding port management table 124 are common techniques in the bridge device 101 as a MAC address table or Forwarding Database, and thus description thereof is omitted in this embodiment.

  The delivery port determination unit 309 delivers the frame using the port number, destination MAC address, transmission source MAC address, and VLAN ID transmitted from the frame classification / information extraction unit 311 according to the state managed by the state management unit 306. A port (hereinafter also referred to as a delivery port) is determined. The delivery port determining unit 309 transmits the port number and the memory address of the frame transmitted from the frame classification / information extracting unit 311 to the transmission / reception control unit 313 corresponding to the determined delivery port.

  Note that the number of delivery ports may be plural or zero. When there are a plurality of delivery ports, the same frame is delivered to each delivery port. If there are no delivery ports, no frame is transferred. That is, the frame is discarded. In some modes described later, the broadcast frame is delivered to all ports except the reception port.

  The delivery port determination unit 309 transmits the destination MAC address, the source MAC address, and the VLAN ID to the port learning unit 310 in a predetermined mode to be described later. The port learning unit 310 searches for an entry that matches the transmitted information (an entry different from the destination and the transmission source). If a matching entry is found, the port number is displayed. If no matching entry is found, The fact that the entry was not found is transmitted to the delivery port determination unit 309.

  The delivery port determination unit 309 determines a port corresponding to the port number included in the search result transmitted from the port learning unit 310 as a delivery port, or determines a delivery port from among ports other than the port, The management unit 306 is notified of the delivery port. The delivery port determination unit 309 notifies the transmission / reception control unit 313 of the port number and the memory address where the frame is stored, and delivers the frame.

  The operation of the delivery port determination unit 309 described above differs depending on the mode of the bridge device 101 and Edge Relay 128. Details will be described later.

  In addition, the state management unit 306 transmits the current state, Chassis ID, ID for identifying the port, expiration date, port MAC address, and destination MAC address to the control frame generation unit 308. As a result, a control frame is transmitted. The trigger for transmitting the control frame will be described later.

  Among the information transmitted from the state management unit 306 to the control frame generation unit 308, the state will be described later. Of the information to be transmitted, information other than the state is acquired from the settings, but the specific information has a general content as an essential TLV of LLDP, and thus the description thereof is omitted in this embodiment.

  The control frame generation unit 308 generates an LLDP frame in which the information transmitted from the state management unit 306 is embedded as a TLV, and stores the generated LLDP frame in the frame accumulation unit 312 of all ports. The control frame generation unit 308 transmits the port number and the address on the storage device 116 for referring to the stored LLDP frame to the transmission / reception control unit 313 of each port.

  The LLDP frame described above is stored only in the frame storage unit 312 of one port, and the port number of the port and the address on the storage device 116 for referring to the LLDP frame are stored in the frame storage unit 312 of all ports. The notification may save the storage capacity required for storing the LLDP frame. The LLDP frame described above may include different contents for each port, such as a Port ID. Further, transmission of LLDP frames may be suppressed at some ports to save a link bandwidth that does not require LLDP frames.

  The contents of the LLDP frame generated by the control frame generation unit 308 will be described later.

  In Edge Relay 128, depending on the state of Edge Relay 128, state management unit 306 may instruct transmission / reception control unit 313 to temporarily stop or resume frame reception. At this time, when the transmission / reception control unit 313 receives the pause or restart instruction, the transmission / reception control unit 313 transmits the frame reception / pause instruction to the frame classification / information extraction unit 311. The state of Edge Relay 128 related to this instruction will be described later.

  When the frame classification / information extraction unit 311 receives a frame reception pause instruction from the transmission / reception control unit 313 and then receives the frame, the frame classification / information extraction unit 311 stores the frame in the frame storage unit 312. Transmission of information to the learning unit 310 is temporarily stopped. When the frame classification / information extraction unit 311 receives an instruction to resume frame reception from the transmission / reception control unit 313, the frame classification / information extraction unit 311 resumes information transmission. In addition, the frame classification / information extraction unit 311 notifies the state management unit 306 that the frame has been saved during the temporary suspension of frame reception.

  Information about the frames saved during the frame reception suspension is transmitted to the delivery port determination unit 309 and the port learning unit 310 in the order received after frame reception is resumed.

  Note that the frame classification / information extraction unit 311 transmits information to the control frame processing unit 307 even when frame reception is temporarily stopped, but, similarly to the transmission of information to the delivery port determination unit 309 and the port learning unit 310, the control frame The transmission of information to the processing unit 307 may be temporarily stopped, and may be simplified so as to be resumed after receiving a restart instruction. The suspension and resumption of the above-described transmission is realized by a mechanism called a queue. However, in information processing, a queue is also called a first in first out (FIFO), and is not described here.

  In addition, it is not always necessary to suspend and resume frame reception by the above-described method. For example, during suspension of frame reception, the transmission / reception control unit 313 queues the entire frame in the order in which it was received, A method of taking out and processing by the transmission / reception control unit 313 may be used. This simplifies the program.

  Next, other processes of the transmission / reception control unit 313 will be described.

  The frame storage unit 312 instructs the transmission / reception control unit 313 to discard the received frame when an instruction from the user is given. The trigger for discarding the received frame is not limited to an instruction from the user. For example, the received frame is discarded when the state managed by the state management unit 306 becomes a predetermined state. The frame may be discarded under specific conditions.

  When the transmission / reception control unit 313 is instructed to discard the received frame from the frame storage unit 312, the transmission / reception control unit 313 instructs the frame classification / information extraction unit 311 to discard the received frame. When the frame classification / information extraction unit 311 receives a frame after receiving an instruction to discard the received frame from the transmission / reception control unit 313, the frame classification / information extraction unit 311 transmits information to the delivery port determination unit 309, the port learning unit 310, and the control frame processing unit 307. Even when the transmission is stopped and the instruction to discard the received frame is canceled, the information about the frame received while the frame reception is stopped is not transmitted.

  The frame classification / information extraction unit 311 instructs the frame storage unit 312 to release the storage area used for the received frame while frame reception is stopped, and the frame storage unit 312 that has received the instruction Is released.

  Although the present invention realizes discarding of received frames by the above-described processing, the present invention is not limited to the above-described processing. For example, the processing of the frame receiving unit 314 may be stopped to realize substantial discarding of received frames. .

  Next, an operation when a frame is transmitted from a port will be described.

  The transmission / reception control unit 313 is a port in which the port number of the frame storage unit 312 in which the transmission target frame transmitted from the control frame processing unit 307 or the delivery port determination unit 309 is stored and the address on the storage device 116 are transmitted. Is different from the frame, the frame is read from the frame storage unit 312 in which the transmission target frame is stored, and stored in the frame storage unit 312 of the port that transmits the frame.

  Then, the transmission / reception control unit 313 instructs the frame storage unit 312 to transmit the transmission target frame to the frame transmission unit 315. The frame accumulation unit 312 transmits the transmission target frame to the frame transmission unit 315 in accordance with the above-described instruction. The frame transmission unit 315 transmits the frame transmitted from the frame storage unit 312.

  The transmission / reception control unit 313 instructs the frame storage unit 312 to delete the transmitted frame, and the frame storage unit 312 deletes the frame. However, since a frame deletion method that maintains consistency when frames are transmitted from a plurality of ports is a general technique as a reference count in information processing, description in this embodiment is omitted.

  In this embodiment, the frame storage unit 312 is provided for each port. However, the number of copies in the storage device 116 can be determined by collecting and managing the frame storage unit 312 for storing frames in the storage device 116. It may be reduced to increase the processing speed and increase the utilization efficiency of the storage device 116. The management of the storage device 116 is a general technique for securing memory, managing memory, and the like in information processing, and thus the description in this embodiment is omitted.

  FIG. 4 is an explanatory diagram illustrating an example of the transfer port management table 124 according to the first embodiment of this invention.

  The transfer port management table 124 includes entries including a MAC address 401, a VLAN_ID 402, and a port ID 403.

  The MAC address 401 is an address for identifying an entity in the Ethernet. VLAN_ID 402 is an identifier of a VLAN in an Ethernet frame defined in IEEE 802.1Q. A frame including a different VLAN ID is treated as another VLAN. The port ID 403 is an identifier for identifying a plurality of ports (representing the input / output port 125 and the port control unit 121 corresponding to the input / output port 125).

  In the case of the virtual machine 130, a virtual MAC address is stored in the MAC address 401, and a virtual port ID is stored in the port ID 403.

  The port learning unit 310 searches for an entry in which the MAC address 401 and VLAN_ID 402 match the transmission source MAC address and VLAN ID transmitted from the frame classification / information extraction unit 311.

  If no matching entry is found, the port learning unit 310 stores the source MAC address and VLAN ID in the MAC address 401 and VLAN_ID 402, stores the transmitted port number in the port ID 403, and adds a new entry. .

  When a matching entry is found, the port learning unit 310 updates the port ID 403 of the entry with the transmitted port number.

  Further, the port learning unit 310 searches for an entry in which the MAC address 401 and VLAN_ID 402 match the MAC address and VLAN ID transmitted from the delivery port determining unit 309.

  If a matching entry is found as a result of the search, the port ID 403 of the entry is transmitted to the delivery port determining unit 309. If a matching entry is not found, the delivery port determining unit 309 is notified that the entry has not been found.

  The forwarding port management table 124 corresponds to Filtering Database in IEEE 802.1Q. Note that the configuration of the transfer port management table 124 is not necessarily limited to the configuration of only the information shown in FIG. 4 as long as the function of determining the port to transfer the frame by comparing the transfer port management table 124 with the frame information can be realized. For example, a configuration of a correspondence table between port IDs for identifying input ports and transfer destination port IDs 403 is also conceivable, and a configuration in which VLAN_ID 402 is omitted (a bridge function defined in IEEE 802.1D) may be used.

  In addition, the forwarding port management table 124 adds a source MAC address, a VLAN ID, and a port number (port ID) of an input frame as an associated entry, and deletes an entry that has not been used for a certain period of time by port learning. Managed. The present invention is not limited to this. For example, a fixed entry may be created and the port learning process may be omitted.

(Control frame)
As described above, the control frame is generated by the bridge device 101 and the control frame generation unit 308 of the Edge Relay 128 and is transmitted from the frame transmission unit 315. The control frame is transmitted when a predetermined period or a specific state change occurs. In addition to what is specified as LLDP, the transmission trigger of a control frame includes what accompanies a state transition described later.

  The transmitted control frame is received by the frame receiving unit 314 of the opposite device (bridge device 101 or Edge Relay 128), and the control frame processing unit 307 processes the frame. The control frame is configured as an LLDP frame defined in IEEE 802.1AB. In this embodiment, the control frame uses each EVB TLV defined in IEEE 802.1Qbg as one of the LLDP TLVs. The status information of the port or Edge Relay 128) is transmitted to the opposite device. Further, the opposing device executes a state transition process based on the received state information.

  FIG. 5 is an explanatory diagram showing the configuration of the EVB TLV in the first embodiment of the present invention.

  FIG. 5 shows what state information is embedded and transmitted in which part of the EVB TLV.

  In the present invention, the bridge device 101 holds state information RRCAP and state information RRCTR for each port, and Edge Relay 128 holds state information RRREQ and state information RRSTAT. Details of the state information described above will be described later.

  In the present invention, the bridge device 101 embeds the state information RRCAP and the state information RRCTR of the port that transmits the control frame of the own device in the RRCAP 504 and the RRCTR 505 included in the EVB_Bridge_status 501 respectively, and the state information RRREQ and the state of the Edge Relay 128 that is the opposite device Information RRSTAT is embedded in RRREQ 506 and RRSTAT 507 included in EVB_station_status 502, respectively, and EVB_Mode 503 is embedded with a value “1” indicating EVB Bridge, and an EVB TLV is generated and transmitted as a control frame.

  In the present invention, Edge Relay 128 embeds status information RRCAP and status information RRCTR of the port connected to Edge Relay 128 of bridge device 101 which is the opposite device in RRCAP 504 and RRCTR 505 included in EVB_Bridge_status 501 respectively, and status information RRREQ of the own device. The status information RRSTAT is embedded in RRREQ 506 and RRSTAT 507 included in the EVB_station_status 502, and the EVB_Mode 503 is embedded with a value “2” indicating the EVB station, and is transmitted as a control frame.

  Further, Edge Relay 128 acquires the status information of the opposing device (port) from the control frame transmitted from the opposing device, and generates a control frame using the acquired status information. When no control frame is received from the opposite device, a control frame in which all the state information of the opposite device is “0” is generated.

  In the EVB TLV defined in the IEEE 802.1Qbg standard, EVB_Bridge_status 501, EVB_station_status 502, EVB_Mode 503, RRCAP 504, RRCTR 505, RRREQ 506, and RRSTAT 507 are the same information in the standard, as shown in FIG. Shall conform to the IEEE 802.1Qbg standard.

  That is, the EVB TLV in which the state information is embedded can be handled as an EVB TLV in accordance with the IEEE 802.1Qbg standard. Therefore, the control frame including the EVB TLV in which the state information is embedded is an LLDP frame and conforms to the IEEE 802.1AB standard.

  In addition, the control frame used in the present invention is not limited to the above-described LLDP frame, and is not limited to the above-described format as long as it can notify the above-described state information. For example, the bridge device 101 may transmit a frame including only the state information RRCAP and the state information RRCTR, and the Edge Relay 128 may transmit a frame including only the state information RRREQ and the state information RRSTAT, thereby saving a transfer amount necessary for transmission of the state information.

  Next, the concept of state information RRCAP, state information RRCTR, state information RRREQ, and state information RRSTAT used in the present invention will be described.

  In the present invention, the bridge device 101 has a function called “Refective Relay”. Reflective Relay is a function that allows further transmission of the frame from the port that received the frame in the Ethernet bridge function.

  In IEEE 802.1Qbg, the value of the status information RRCAP is “1” when the EVB Bridge (corresponding to the bridge device 101) has the reactive relay function, and “0” when the reflective relay function is not provided. It is stipulated that. In the present invention, the value of the state information RRCAP is changed to “0” or “1” according to the mode of the bridge device 101 described later.

  In IEEE 802.1Qbg, the value of the status information RRCTR is defined to be “1” when EVB Bridge is operating as a Reflective Relay, and “0” when not operating as a Reflexive Relay. ing. Similarly, in the present invention, the value is “1” when the bridge device 101 is operating as a reactive relay, and the value is “0” when the bridge device 101 is not operating as a reactive relay.

  In IEEE 802.1Qbg, the value of status information RRREQ is “1” when Edge Relay (equivalent to Edge Relay 128) of EVB station (equivalent to server device 102) wants EVB Bridge to operate as Reflective Relay. It is stipulated that “0” is set when the operation as a reactive relay is not desired. Similarly, in the present invention, the value is “1” when the Edge Relay 128 desires the bridge device 101 to operate as a Reflective Relay, and the value is “0” when it does not desire to operate as the Reflective Relay. To do.

  In IEEE 802.1Qbg, the value of the status information RRSTAT is “0” when the EVB station determines that the EVB Bridge is operating, and the EVB Bridge is not operating as the Reflexive Relay, and the EVB Bridge is Reflective. It is specified that “1” is set when it is determined that the relay is operating, and “2” or “3” is set when the operation of EVB Bridge is unknown. Similarly, in the present invention, Edge Relay 128 determines the operation of bridge device 101, and when it is determined that bridge device 101 is not operating as a reactive relay, the value is “0”, and bridge device 101 operates as a reactive relay. If it is determined that the bridge device 101 is in operation, the value is “1”. If the operation of the bridge device 101 is unknown, the value is “2”.

  The concept of the state information of the bridge device 101 and Edge Relay 128 is as described above, but the state transition accompanying the change of the state information will be described later.

  Hereinafter, state information RRCAP, state information RRCTR, state information RRREQ, and state information RRSTAT are also simply referred to as RRCAP, RRCTR, RRREQ, and RRSTAT.

(Mode and state in Edge Relay and bridge device)
Next, modes and states in the bridge device 101 and Edge Relay 128 will be described.

  FIG. 6 is an explanatory diagram illustrating modes and state transitions in Edge Relay 128 according to the first embodiment of this invention.

  In FIG. 6, a dotted square represents a mode, a solid square represents a state, and an arrow represents a state transition.

  As shown in FIG. 6, Edge Relay 128 corresponds to a combination of two state information of RRSTAT and RRREQ, and includes 6 of S0 state 604, S1 state 605, S2 state 606, S3 state 607, S4 state 608 and S5 state 609. It can take any one of the states.

  The Edge Relay 128 operates in a mode corresponding to each state. In each mode, the operation at the time of transfer of the received frame is different and includes one or a plurality of states. Specifically, Edge Relay 128 operates in the VEB mode 601 when in the S0 state 604, operates in the VEPA mode 602 when in the S3 state 607, and operates in the S1 state 605, the S2 state 606, the S4 state 608, and the S5 state. In any case of 609, the TRAN mode 603 is operated.

  The operation of Edge Relay 128 in each mode will be described later. Moreover, the transition between each state is also mentioned later.

  Six states are associated with RRREQ and RRSTAT. Specifically, the state in which RRSTAT is “0” and RRREQ is “0” is the S0 state 604, the state in which RRSTAT is “0” and RRREQ is “1”, the state S1 605, and the RRSTAT is “1” and RRREQ. Is in the S2 state 606, the RRSTAT is “1” and the RRREQ is “1” in the S3 state 607, the RRSTAT is “2” and the RRREQ is “0” in the S4 state 608, A state in which RRSTAT is “2” and RRREQ is “1” is associated with the S5 state 609.

  As described above, the Edge Relay 128 transmits the RRREQ and RRSTAT, that is, the state of the Edge Relay 128 to the bridge device 101 using the control frame described with reference to FIG.

  FIG. 7 is an explanatory diagram illustrating modes and state transitions in the ports of the bridge device 101 according to the first embodiment of this invention.

  In FIG. 7, dotted squares represent modes, solid squares represent states, and arrows represent state transitions.

  As shown in FIG. 7, the port of the bridge apparatus 101 is one of four types of B0 state 703, B1 state 704, B2 state 705, and B3 state 706 corresponding to a combination of two state information of RRCAP and RRCTR. Take the state.

  Four types of states are associated with RRCAP and RRCTR. Specifically, a state in which RRCAP is “0” and RRCTR is “0” is a B0 state 703, a state in which RRCAP is “0” and RRCTR is “1” is a B1 state 704, and RRCCAP is “1” and RRCTR. Is associated with the B2 state 705, and the state where RRCAP is "1" and RRCTR is "1" is associated with the B3 state 706.

  Further, the port of the bridge device 101 operates in a mode corresponding to each state. In each mode, the operation at the time of transfer of the received frame is different and includes one or a plurality of states. Specifically, the port of the bridge device 101 operates in the SW mode 701 when in the B0 state 703 or B2 state 705 and operates in the RR mode 702 when in the B3 state 706 or B1 state 704.

  The bridge device 101 maintains an independent state for each port, and operates in an independent mode for each port. That is, one port and another port of the bridge device 101 may be in different states or modes. The operation of the bridge device 101 in each mode will be described later. Moreover, the state transition between each state is also mentioned later.

  As described above, the bridge device 101 transmits the RRCAP and RRCTR in each port, that is, the state of the port of the bridge device 101 to the Edge Relay 128 using the control frame described with reference to FIG.

  Here, the relationship between the Edge Relay 128 mode and the port mode of the bridge device 101 will be described.

  Basically, the Edge Relay 128 mode is linked to the mode of the port of the bridge device 101 which is the opposite device. Specifically, when the port of the bridge device 101 operates in the SW mode 701, the Edge Relay 128 operates in the VEB mode 601, and when the port of the bridge device 101 operates in the RR mode 702, the Edge Relay 128 operates in the VEPA mode. It operates at 602.

  The Edge Relay 128 operates in the TRAN mode 603 when the port mode of the bridge device 101 is changed. Although details will be described later, in the case of the VEB mode 601, the Edge Relay 128 operates as a virtual edge bridge (VEB), that is, as a general network switch. At this time, Edge Relay 128 executes a switching process necessary for communication between the virtual machine 130-1 and the virtual machine 13-2.

  On the other hand, in the case of the VEPA mode 602, the Edge Relay 128 operates as a Virtual Edge Port Aggregator (VEPA). At this time, in the communication between the virtual machine 130-1 and the virtual machine 130-2, the frame is once transferred from the Edge Relay 128 to the bridge device 101, and the bridge device 101 executes a switching process.

  The operation differs between the case where the mode of the port of the bridge device 101 is the SW mode 701 and the case where the mode is the RR mode 702 as follows. That is, in the operation in the SW mode 701, the frame is not transferred to the port that received the frame, but in the operation in the RR mode 702, the frame is transferred to the port that received the frame.

  The port of the bridge device 101 that operates in the SW mode 701 operates as a general network switch in the same manner as the Edge Relay 128 that operates in the VEB mode 601. In the SW mode 701, the reason why the frame is not transferred to the port that received the frame is to prevent the device connected to the port from receiving the same frame repeatedly.

  However, when the device connected to the port is operating as VEPA, that is, when Edge Relay 128 operating in the VEPA mode 602 is connected to the port, it is necessary to operate in the RR mode 702. This is because the Edge Relay 128 operates on the premise that the bridge device 101 returns to the Edge Relay 128 when the frame transferred to the bridge device 101 needs to be transferred to the virtual machine 130 connected to the Edge Relay 128.

  That is, Edge Relay 128 that operates in VEB mode 601 cannot be connected to a port that operates in RR mode 702, and Edge Relay 128 that operates in VEPA mode 602 cannot be connected to a port that operates in SW mode 701.

  In the present invention, when the VEB mode 601 and the VEPA mode 602 are dynamically switched, the TRAN mode 603 is introduced in order to continue communication correctly even in a transient state.

  In the TRAN mode 603, based on the operation of the VEB mode 601, when the transmission source address is learned by another port among the frames input from the port connected to the bridge apparatus 101, or in another port. If registered, the frame is discarded and port learning is not performed. That is, in the TRAN mode 603, when the frame transferred from the Edge Relay 128 to the bridge device 101 is further transferred from the bridge device 101 to the Edge Relay 128, that is, when the frame is folded, the Edge Relay 128 discards the frame. Prevent receiving duplicate frames.

  Therefore, there is no problem even if Edge Relay 128 operating in TRAN mode 603 is connected to a port operating in RR mode 702. Further, when the port is in SW mode 701, the folded frame is not transferred. The problem at the time of frame transfer is eliminated. However, the operation of Edge Relay 128 in the TRAN mode 603 is also limited.

  For example, if the virtual machine 130-2 connected to the Edge Relay 128 operating in the TRAN mode 603 in the server apparatus 102-1 and transmitting the frame to the virtual machine 130-1 moves to the server apparatus 102-2, the movement As before, since the frame transmitted from the virtual machine 130-2 to the virtual machine 130-1 reaches the Edge Relay 128 via the bridge device 101, the frame is discarded according to the operation of the TRAN mode 603, and the communication is cut off. End up.

  In the present invention, the Edge Relay 128 mode is changed to the transient TRAN mode 603 only when the VEB mode 601 and the VEPA mode 602 are switched in order to suppress the occurrence of the above-described communication interruption.

  Regarding the modes of the Edge Relay 128 and the bridge device 101, operations including switching in each mode will be described later.

  Next, the positioning of each state information when transmitting a control frame including the state information in FIG. 6 from the Edge Relay 128 to the bridge device 101 will be described.

  The control frame that notifies the S0 state 604 has a role of notifying the bridge device 101 that the Edge Relay 128 is currently operating in the VEB mode 601.

  The control frame notifying the S1 state 605 or the S5 state 609 notifies the bridge device 101 that the Edge Relay 128 is currently operating in the TRAN mode 603, and further operates in the RR mode 702 in order to operate in the VEPA mode 602. There is a role to request the bridge device 101 to do so.

  The control frame that notifies the S3 state 607 has a role of notifying the bridge device 101 that the Edge Relay 128 is currently operating in the VEPA mode 602.

  The control frame notifying the S2 state 606 or the S4 state 608 notifies the bridge device 101 that the Edge Relay 128 is currently operating in the TRAN mode 603, and further operates in the SW mode 701 in order to operate in the VEB mode 601. There is a role to request the bridge device 101 to do so.

  Next, the positioning of each state information when transmitting a control frame including the state information in FIG. 7 from the bridge apparatus 101 to the Edge Relay 128 will be described.

  The control frame that notifies the B0 state 703 has a role of notifying the Edge Relay 128 that the bridge device 101 is currently operating in the SW mode 701.

  The control frame notifying the B2 state 705 notifies that the bridge device 101 is currently operating in the SW mode 701, and further requests the Edge Relay 128 to operate in the VEPA mode 602 in order to operate in the RR mode 702. There is a role.

  The control frame that notifies the B3 state 706 has a role of notifying that the bridge device 101 is currently operating in the RR mode 702.

  The control frame notifying the B1 state 704 notifies that the bridge device 101 is currently operating in the RR mode 702, and further requests the Edge Relay 128 to operate in the VEB mode 601 in order to operate in the SW mode 701. There is a role.

  As described above, in the present invention, the control frame including the state information shown in FIG. 6 and FIG. 7 has a role of notifying the state of each device and requesting the connected device for mode transition. is there.

  The Edge Relay 128 and the bridge device 101 operate according to a mode transition instruction so as to transmit the control frame described above and to enter an appropriate mode when receiving the control frame.

  Hereinafter, operations of the Edge Relay 128 and the bridge device 101 will be described below. In the following description, the variable name represents the value stored in the variable.

(Operation of Edge Relay)
8A and 8B are flowcharts for explaining processing executed by Edge Relay 128 according to the first embodiment of this invention.

  When the Edge Relay 128 is activated, it is initialized after executing initialization of the program such as confirmation of hardware and settings (step S801).

  The state management unit 306 manages the variable “RRSTAT” and the variable “RRREQ”, and based on the combination of the values of each variable, the S0 state 604, the S1 state 605, the S2 state 606, the S3 state 607, and the S4 state 608 And S5 state 609 are managed. Further, the state management unit 306 changes each state when state transition is necessary.

  The state management unit 306 manages the variable “RRCAP” and the variable “RRCTR”, and the state of the port of the bridge device 101 connected to the Edge Relay 128 is set to the B0 state 703 based on the combination of the values of each variable. It manages which state is the B1 state 704, the B2 state 705, and the B3 state 706. In addition, when the state of the port cannot be grasped, the state management unit 306 can recognize that the state of the port is unknown.

  Further, the state management unit 306 manages the variable “transfer stop state”, and manages whether or not it is a transfer stop state in which the transfer of the received frame is stopped based on the value of the variable.

  Here, the state management unit 306 sets so as to be in the S4 state 608 in initialization. In the initialization, the state management unit 306 sets the value of the variable “RRCAP” to “2” and the value of the variable “RRCTR” to “0”, and sets the value of the bridge device 101 connected to the Edge Relay 128, for example. The port status is “Unknown”. Further, it is assumed that the state management unit 306 is not in a transfer stopped state during initialization.

  When entering the start state, the state management unit 306 first determines whether or not a transition instruction has been accepted (step S802). Here, the transition instruction is either a transition instruction to the VEB mode 601 or a transition instruction to the VEPA mode 602, and is given by setting or externally.

  In the determination in step S802, it is determined that the transition instruction is received only once every time the transition instruction is received. That is, the determination result is “YES” only once for one transition instruction. For example, the state of the transition instruction is saved in a variable or the like every time, the previous and current transition instructions are compared, and if there is a change and the current transition instruction is “YES”, for example, realizable.

  When it is determined that the transition instruction has been received, the state management unit 306 records information regarding the transition instruction, and proceeds to step S804 (step S803). Specifically, a variable “transition instruction state” indicating that the transition instruction has been received and whether the transition instruction is a transition instruction to the VEB mode 601 or a transition instruction to the VEPA mode 602 is recorded. .

  The state management unit 306 executes state transition processing in Edge Relay 128, and proceeds to step S805 (step S804). Details of the state transition process in Edge Relay 128 will be described later.

  After the state transition process ends, the state management unit 306 refers to the variable “transition instruction state” and determines whether or not a transition instruction is recorded (step S805). When a value indicating a transition instruction to the VEB mode 601 or a transition instruction to the VEPA mode 602 is stored in the variable “transition instruction state”, it is determined that the transition instruction is recorded.

  When it is determined that the transition instruction is not recorded, the state management unit 306 returns to step S802 and executes the same processing.

  When it is determined that the transition instruction is recorded, the state management unit 306 refers to the variable “transition instruction state”, the variable “RRSTAT”, and the variable “RRREQ”, and the transition instruction to the VEB mode 601 is recorded. In addition, it is determined whether or not the state is the S0 state 604 (step S806).

  If it is determined that the determination condition in step S806 is satisfied, the state management unit 306 responds to the accepted transition instruction that the process has succeeded, and the process proceeds to step S808 (step S807). As a response method, for example, a method of outputting information indicating success through the input / output device 117 and responding by transmitting a frame including information indicating success through the port is conceivable. In addition, the information may be notified together with the state notification by the control frame. Note that this process may be omitted when a response to the transition instruction is not required.

  The state management unit 306 deletes the variable “transition instruction state”, returns to step S802, and executes the same processing (step S808). Here, as a method for deleting the variable “transition instruction state”, for example, a value different from the value indicating the transition instruction is substituted. Note that in the start state, the variable “transition instruction state” is in a deleted state.

  If it is determined in step S806 that the determination condition in step S806 is not satisfied, the state management unit 306 refers to the variable “transition instruction state”, the variable “RRSTAT”, and the variable “RRREQ”, and transitions to the VEPA mode 602. It is determined whether or not the instruction is recorded and the state is the S3 state 607 (step S809).

  If it is determined that the determination condition in step S809 is satisfied, the state management unit 306 proceeds to step S807.

  When it is determined that the determination condition in step S809 is not satisfied, the state management unit 306 refers to the variable “transition instruction state”, the variable “RRSTAT”, and the variable “RRREQ”, and the transition instruction to the VEPA mode 602 is recorded. And it is determined whether it is S2 state 606 (step S810). As a response method, the same method as in step S808 is used. Note that this process may be omitted when a response to the transition instruction is not required.

  When it is determined that the determination condition of step S810 is not satisfied, the state management unit 306 returns to step S802 and executes the same processing.

  When it is determined that the determination result in step S810 is satisfied, the state management unit 306 responds to the transition instruction that the failure has occurred, and proceeds to step S808 (step S811).

  If it is determined in step S802 that a transition instruction has not been received, the state management unit 306 determines whether the port has received a frame based on information transmitted from the frame classification / information extraction unit 311. (Step S812).

  When it is determined that the frame has been received, the state management unit 306 determines whether the frame is a control frame based on the information transmitted from the frame classification / information extraction unit 311 (step S813).

  If it is determined that the control frame has been received, the state management unit 306 proceeds to step S804. At this time, the state management unit 306 acquires the content of the control frame received from the control frame processing unit 307, and sets values for the variable “RRCAP” and the variable “RRCTR” based on the acquired content.

  When it is determined that the control frame has not been received, the state management unit 306 refers to the variable “transfer stop state” and determines whether or not the transfer frame is in a stop state (step S814).

  When it is determined that the transfer is stopped, the state management unit 306 connects the port that received the frame in step S812 to the bridge device 101 based on the information transmitted from the frame classification / information extraction unit 311. It is determined whether or not the port is a UPLINK port (step S815).

  When it is determined that the port that has received the frame is a UPLINK port, the state management unit 306 executes the frame transfer process in Edge Relay 128 for the frame to be processed, and the process proceeds to step 817 (step S816). Details of the frame transfer process in Edge Relay 128 will be described later.

  After executing the frame transfer process, the state management unit 306 determines whether there is a frame delivered from the delivery port determining unit 309 to each port (step S817).

  If it is determined that there is no frame delivered to the port, the state management unit 306 returns to step 802 and executes the same processing.

  When it is determined that there is a frame delivered to the port, the state management unit 306 instructs the transmission / reception control unit 313 to transmit the delivered frame, and then returns to step S802 to execute the same processing (step S818). ).

  If it is determined in step S814 that the transfer is not stopped, the state management unit 306 determines whether there is a frame stored in the frame storage unit 312 based on the information transmitted from the frame classification / information extraction unit 311. It is determined whether or not (step S819).

  If it is determined that there is no accumulated frame, the state management unit 306 proceeds to step S816.

  If it is determined that there is an accumulated frame, the state management unit 306 sets the accumulated frame and the received frame in the order of transfer processing, and proceeds to step S816 (step S820).

  If it is determined in step S812 that no frame has been received, the state management unit 306 refers to the variable “transfer stop state” and determines whether or not the transfer is stopped (step S821).

  When it is determined that the transfer is stopped, the state management unit 306 returns to step S802 and executes the same processing.

  When it is determined that the transfer is not stopped, the state management unit 306 determines whether there is a frame stored in the frame storage unit 312 based on the information transmitted from the frame classification / information extraction unit 311. (Step S822).

  If it is determined that there is no accumulated frame, the state management unit 306 returns to step S802 and executes the same processing.

  When it is determined that there is an accumulated frame, the state management unit 306 sets the frame accumulated in the frame accumulation unit 312 as a processing target, and proceeds to step S816 (step S823).

  If it is determined in step S815 that the port that received the frame is not a UPLINK port, the state management unit 306 stores the received frame in the frame storage unit 312 as it is in the frame reception unit 314 because the transfer is currently stopped. And returns to step 802 to execute similar processing (step S824).

  The outline of the processing executed by Edge Relay 128 described above is as follows.

  First, the Edge Relay 128 executes an initialization process. If there is a transition instruction (YES in step S802), Edge Relay 128 executes state transition processing (step S804). EdgeRelay128 returns a response (step S807, step S811), and returns to the beginning (step S802), when the result of a process comes out (step S806, step S809, step S810).

  If there is no transition instruction and a control frame is received (YES in step S813), EdgeRelay 128 executes state transition processing (step S804), and then returns to the beginning (step S802).

  When there is no transition instruction, a frame other than the control frame is received and the transfer is stopped (YES in step S814), Edge Relay 128 stores the received frame for ports other than the UPLINK port (step S824). . On the other hand, when the transfer is stopped and the port that received the frame is a UPLINK port or when the transfer is not stopped, Edge Relay 128 executes the frame transfer process (step S816), and based on the execution result. The frame is transmitted (step S818).

  If there is no transition instruction, no frame is received, and there is a frame accumulated in the transfer stop state (YES in step S822), Edge Relay 128 sets the accumulated frame as a processing target (step S821), and transfers the frame. The process is executed (step S816), and a frame is transmitted based on the execution result (step S818).

(Frame transfer processing)
Next, the frame transfer process in Edge Relay 128 will be described.

  FIG. 9 is a flowchart for describing frame transfer processing in Edge Relay 128 according to the first embodiment of this invention.

  When the start of the frame transfer process in Edge Relay 128 is instructed, a start state is entered and the process is started (step S901).

  The Edge Relay 128 determines whether or not the current state is the S0 state 604, that is, the VEB mode 601 (step S902). Specifically, the state management unit 306 refers to the variable “RRSTAT” and the variable “RRREQ” and determines whether or not the current state is the VEB mode 601.

  If it is determined that the current state is the VEB mode, Edge Relay 128 executes port learning and proceeds to step S904 (step S903). Specifically, the state management unit 306 instructs the port learning unit 310 to execute port learning, and the port learning unit 310 that has received the instruction performs port learning using the transmission source MAC address and VLAN ID of the target frame. Run.

  Next, Edge Relay 128 searches for a delivery port (step S904). Specifically, the delivery port determination unit 309 instructs the port learning unit 310 to search for a port corresponding to the destination MAC address and VLAN ID of the target frame, that is, a learned port. If a corresponding port is found, the port (one or more) is determined as a delivery port. If no corresponding port is found, all ports are determined as delivery ports. When the port learning process is omitted, if a frame for which no corresponding port is found is received or a multicast frame is received, the number of delivery ports is zero for frames with a specific destination, and the frame is discarded. In this way, resources such as a transfer band may be saved.

  Edge Relay 128 excludes the port that received the target frame from the delivery port, determines the delivery port, and proceeds to step S906 (step S905). Specifically, the delivery port determination unit 309 excludes the port that received the target frame transmitted from the frame classification / information extraction unit 311 from the delivery ports determined in step S904, and sets the remaining ports as new ones. Determine as delivery port.

  The Edge Relay 128 delivers the frame from the delivery port and ends the process (Steps S906 and S907). Specifically, the delivery port determining unit 309 delivers the target frame to the determined delivery port.

  If it is determined in step S902 that the current state is not the VEB mode, Edge Relay 128 determines whether or not the current state is the S3 state 607, that is, the VEPA mode (step S908). Specifically, the state management unit 306 determines whether or not the current state is the S3 state 607 with reference to the variable “RRSTAT” and the variable “RRREQ”.

  If it is determined that the current state is the VEPA mode, the Edge Relay 128 determines whether the port that received the frame is a port connected to the bridge device 101, that is, a UPLINK port (step S909). Specifically, based on the information transmitted from the frame classification / information extraction unit 311, the state management unit 306 determines whether the port that received the target frame is a UPLINK port.

  If it is determined that the port that received the target frame is a UPLINK port, Edge Relay 128 proceeds to step S904.

  If it is determined that the port that has received the target frame is not a UPLINK port, Edge Relay 128 performs port learning and proceeds to step S911 (step S910). Specifically, the state management unit 306 instructs the port learning unit 310 to execute port learning, and the port learning unit 310 that has received the instruction performs port learning using the source MAC address and VLAN ID of the target frame. Run.

  The Edge Relay 128 determines a delivery port after executing port learning, and proceeds to Step S906 (Step S911). Specifically, the delivery port determining unit 309 determines only the UPLINK port as the delivery port.

  If it is determined in step S908 that the current state is not the VEPA mode, that is, the TRAN mode, Edge Relay 128 is a port to which the port receiving the target frame is connected to the bridge device 101, that is, a UPLINK port. It is determined whether or not (step S912). Specifically, the delivery port determination unit 309 determines whether the port that received the target frame is a UPLINK port based on the information transmitted from the frame classification / information extraction unit 311.

  If it is determined that the port that received the target frame is not a UPLINK port, Edge Relay 128 proceeds to step S903.

  If it is determined that the port that has received the target frame is a UPLINK port, Edge Relay 128 determines whether or not the transmission source address has been registered (step S913). Specifically, the delivery port determination unit 309 instructs the port learning unit 310 to search for a port learned based on the transmission source address and VLAN ID of the target frame, and determines whether or not the port is found. . When the transmission source address is already registered, it indicates that the frame is transmitted from the device (virtual machine 130) to which Edge Relay 128 is connected.

  If it is determined that the transmission source address has not been registered, Edge Relay 128 proceeds to step S903.

  If it is determined that the transmission source address has been registered, Edge Relay 128 discards the frame and ends the process (step S914). Specifically, the delivery port determination unit 309 instructs the transmission / reception control unit 313 to discard the target frame.

  As described above, the frame transfer process in Edge Relay 128 differs depending on the mode. The outline of the process is as follows.

  First, the Edge Relay 128 determines in which mode it is operating (Step S902, Step S908).

  When operating in the VEB mode 601, Edge Relay 128 performs port learning (step S903), determines a port other than the reception port as a delivery port from the search result of the delivery port (step S904, step S905), and the delivery. The frame is delivered to the port (step S906).

  When operating in the VEPA mode 602, the Edge Relay 128 receives a frame from the UPLINK port (YES in step S909), does not perform port learning, and delivers the frame in the same manner as in the VEB mode 601 (step S904, Step S905, Step S906). On the other hand, when operating in the VEPA mode 602, when receiving a frame from a port other than the UPLINK port, Edge Relay 128 performs port learning (step S910), and delivers the frame to the UPLINK port (step S911, step S906). ).

  When operating in the TRAN mode 603, when a frame is received from the UPLINK port and the source learning result in the non-UPLINK port indicates that the source address is connected to the non-UPLINK port, The Edge Relay 128 discards the frame (step S914). On the other hand, in other cases, Edge Relay 128 executes the same processing as in VEB mode 601.

(State transition process)
Next, the state transition process in Edge Relay 128 executed in step S805 will be described.

  10A to 10F are flowcharts illustrating the state transition process in Edge Relay 128 according to the embodiment of this invention.

  The acquisition of the Edge Relay 128 status and the reception of the control frame including the status information of the port of the bridge device 101 have been described with reference to FIG.

  Note that the state of the Edge Relay 128 is changed by changing the values of the variable “RRSTAT” and the variable “RRREQ”. Therefore, when the state of Edge Relay 128 is changed, it means that the values of the variable “RRSTAT” and the variable “RRREQ” have been changed.

  In addition, the state management unit 306 holds variables “transition standby start time” and “transfer stop start time”, and these variables are the same when the state transition process is executed again after the state transition process is completed. The value of can be referred to.

  Further, the state management unit 306 holds the setting “transition standby time” and the setting “reception standby time”.

  Further, the variable “transfer stop state” and the variable “transition instruction state” are the same as the variables described in FIG.

  Note that the state transition process described below is executed when a transition instruction is received or a control frame is received. In the following description, the expression “received a control frame including state information” means that the state information (B0 state 703, B1 state 704, B2 state 705 or B3 state 706) is included in the control frame that triggers the state transition process. It is meant to be included. In addition, the state management unit 306 can update the variable “RRCAP” and the variable “RRCTR” according to the contents of the control frame, and can acquire the state information of the bridge device 101 with reference to the variable “RRCAP” and the variable “RRCTR”.

  When the state transition process in Edge Relay 128 is started (step S1001), the state management unit 306 refers to the variable “transfer stop state” to determine whether or not the transfer stop state is set (step S1002).

  As described with reference to FIG. 8, the state transition process is started when a transition instruction or a control frame is received.

  The state management unit 306 updates the variable “RRCAP” and the variable “RRCTR” according to the information included in the control frame, and refers to the variable “RRCAP” and the variable “RRCTR” to determine the port state information in the bridge device 101. Can be obtained.

  If it is determined that the transfer is stopped, the state management unit 306 proceeds to step S1021.

  When it is determined that the transfer is not stopped, the state management unit 306 determines whether a control frame including the B0 state 703 has been received (step S1003).

  If it is determined that a control frame including the B0 state 703 has not been received, the state management unit 306 proceeds to step S1031.

  If it is determined that a control frame including the B0 state 703 has been received, the state management unit 306 determines whether the current Edge Relay 128 state corresponds to either the S2 state 606 or the S4 state 608 (step S1004). ).

  When it is determined that the determination condition of step S1004 is satisfied, the state management unit 306 changes the state of Edge Relay 128 to the S0 state 604 and proceeds to step S1006 (step S1005).

  The state management unit 306 transmits a control frame including state information for notifying the current state, and ends the process (steps S1006 and S1007). Specifically, the state management unit 306 instructs the control frame generation unit 308 to generate a control frame, and transmits the generated control frame to the bridge device 101.

  If it is determined in step S1004 that the determination condition of step S1004 is not satisfied, the state management unit 306 determines whether or not the current Edge Relay 128 state is the S5 state 609 (step S1008).

  If it is determined that the determination condition of step S1008 is satisfied, the state management unit 306 changes the state of Edge Relay 128 to the S1 state 605 and proceeds to step S1010 (step S1009).

  The state management unit 306 stores the current time in the variable “transition standby start time”, and proceeds to step S1006 (step S1010).

  If it is determined in step S1008 that the determination condition in step S1008 is not satisfied, the state management unit 306 determines whether or not the current Edge Relay 128 state is the S3 state 607 (step S1011).

  When it is determined that the determination condition of step S1011 is satisfied, the state management unit 306 changes the state of Edge Relay 128 to the S2 state 606 and proceeds to step 1010 (step S1012).

  When it is determined that the determination condition of step S1011 is not satisfied, the state management unit 306 determines whether or not the current Edge Relay 128 state is the S1 state 605 (step S1013).

  When it is determined that the determination condition of step S1013 is not satisfied, that is, when the current Edge Relay 128 state is the S0 state 604, the state management unit 306 ends the process (step S1007).

  When it is determined that the determination condition of step S1013 is satisfied, the state management unit 306 determines whether or not the time set as the transition standby time has elapsed (step S1014).

  Specifically, the state management unit 306 calculates a time difference by subtracting the time of the variable “transition standby start time” from the current time, and the calculated time difference is larger than the value of the set “transition standby time”. It is determined whether or not. When the calculated time difference is larger than the value of the setting “transition standby time”, it is determined that the transition standby time has elapsed.

  If it is determined that the time set for the transition standby time has elapsed, the state management unit 306 proceeds to step S1012. On the other hand, when it is determined that the time set as the transition standby time has elapsed, the state management unit 306 ends the process (step S1007).

  If it is determined in step S1002 that the transfer is stopped, the state management unit 306 determines whether or not the reception standby time has elapsed (step S1021).

  Specifically, the state management unit 306 calculates the time difference by subtracting the time of the variable “transfer stop start time” from the current time, and the calculated time difference is greater than the value of the set “reception standby time”. It is determined whether or not. When the calculated time difference is larger than the value of the setting “reception standby time”, it is determined that the reception standby time has elapsed.

  When it is determined that the reception standby time has not elapsed, the state management unit 306 ends the process (step S1007).

  When it is determined that the reception standby time has elapsed, the state management unit 306 determines whether or not the current Edge Relay 128 state is the S3 state 607 (step S1023).

  When it is determined that the determination condition of step S1023 is satisfied, the state management unit 306 changes the state of Edge Relay 128 to the S2 state 606, and proceeds to step S1022A (step S1024).

  Then, the state management unit 306 cancels the transfer stop state, and proceeds to step S1010 (step S1022A). Specifically, a value indicating a state other than the transfer stop state is set in the variable “transfer stop state”.

  When it is determined that the determination condition of step S1023 is not satisfied, the state management unit 306 changes the state of Edge Relay 128 to the S3 state 607, and proceeds to step S1022B (step S1025).

  Then, the state management unit 306 cancels the transfer stop state, and proceeds to step S1006 (step S1022B). Specifically, a value indicating a state other than the transfer stop state is set in the variable “transfer stop state”.

  In step S1003, when it is determined that the determination condition of step S1003 is not satisfied, the state management unit 306 receives a control frame including the B1 state 704 or determines whether a transition instruction to the VEB mode 601 has been received. Determination is made (step S1031).

  The state management unit 306 can determine whether or not a transition instruction to the VEB mode 601 has been received by referring to the variable “transition instruction state”. If at least one of the conditions is met, it is determined that the determination condition of step S1031 is satisfied.

  When it is determined that the determination condition of step S1031 is not satisfied, the state management unit 306 proceeds to step S1041.

  When it is determined that the determination condition of step S1031 is satisfied, the state management unit 306 determines whether or not the current Edge Relay 128 state is the S3 state 607 (step S1032).

  When it is determined that the determination condition of step S1032 is satisfied, the state management unit 306 proceeds to step S1061.

  When it is determined that the determination condition in step S1032 is not satisfied, the state management unit 306 determines whether the current Edge Relay 128 state corresponds to any of the S1 state 605, the S4 state 608, or the S5 state 609 ( Step S1033).

  When the current state of Edge Relay 128 corresponds to any of the S1 state 605, the S4 state 608, and the S5 state 609, it is determined that the determination condition of step S1033 is satisfied.

  If it is determined that the determination condition of step S1033 is not satisfied, the state management unit 306 proceeds to step S1006.

  When it is determined that the determination condition of step S1033 is satisfied, the state management unit 306 receives a control frame including the B1 state 704, or determines whether the state of the Edge Relay 128 is the S1 state 605 (step S1034). ). If at least one of the conditions is met, it is determined that the determination condition of step S1034 is satisfied.

  If it is determined that the determination condition of step S1034 is not satisfied, the state management unit 306 proceeds to step S1036.

  When it is determined that the determination condition of step 1034 is satisfied, the state management unit 306 changes the state of Edge Relay 128 to the S2 state 606 and proceeds to step S1010 (step S1035).

  When it is determined that the determination condition of step S1034 is not satisfied, the state management unit 306 determines whether or not the current Edge Relay 128 state is the S5 state 609 (step S1036).

  If it is determined that the determination condition in step S1036 is not satisfied, the state management unit 306 proceeds to step S1006.

  When it is determined that the determination condition of step S1036 is satisfied, the state management unit 306 changes the state of Edge Relay 128 to the S4 state 608 and proceeds to step S1010 (step S1037).

  When it is determined in step S1031 that the determination condition of step S1031 is not satisfied, the state management unit 306 receives a control frame including the B2 state 705 or determines whether or not an instruction to transition to the VEPA mode 602 has been received. Determination is made (step S1041). The state management unit 306 can determine whether or not an instruction to transition to the VEPA mode 602 has been received by referring to the variable “transition instruction state”. If at least one of the conditions is met, it is determined that the determination condition of step S1041 is satisfied.

  If it is determined that the determination condition of step S1041 is not satisfied, the state management unit 306 proceeds to step 1051.

  When it is determined that the determination condition of step S1041 is satisfied, the state management unit 306 determines whether the current Edge Relay 128 state corresponds to any of the S0 state 604, the S2 state 606, the S4 state 608, or the S5 state 609. Determination is made (step S1042).

  When the current Edge Relay 128 state corresponds to any of the S0 state 604, the S2 state 606, the S4 state 608, or the S5 state 609, it is determined that the determination condition of step S1042 is satisfied.

  If it is determined that the determination condition of step S1042 is not satisfied, the state management unit 306 proceeds to step S1006.

  When it is determined that the determination condition of step S1042 is satisfied, the state management unit 306 receives a control frame including the B2 state 705, or whether the state of the Edge Relay 128 corresponds to either the S0 state 604 or the S2 state 606 It is determined whether or not (step S1043). If at least one of the conditions is met, it is determined that the determination condition of step S1043 is satisfied.

  When it is determined that the determination condition of step S1043 is satisfied, the state management unit 306 changes the state of Edge Relay 128 to the S1 state 605 and proceeds to step S1010 (step S1044).

  When it is determined that the determination condition in step S1043 is not satisfied, the state management unit 306 determines whether or not the current Edge Relay 128 state is the S4 state 608 (step S1045). If it is determined that the determination condition in step S1045 is not satisfied, the state management unit 306 proceeds to step S1006.

  When it is determined that the determination condition of step S1045 is satisfied, the state management unit 306 changes the state of Edge Relay 128 to the S5 state 609 and proceeds to step S1010 (step S1046).

  If it is determined in step S1041 that the determination condition of step S1041 is not satisfied, that is, if it is determined that a control frame including the B3 state 706 has been received, the state management unit 306 determines that the current Edge Relay 128 state is the S1 state. It is determined whether it corresponds to either 605 or S5 state 609 (step S1051).

  If it is determined that the determination condition of step S1051 is not satisfied, the state management unit 306 proceeds to step S1061.

  When it is determined that the determination condition of step S1051 is satisfied, the state management unit 306 determines whether or not the current Edge Relay 128 state is the S4 state 608 (step S1052).

  When it is determined that the determination condition of step S1052 is satisfied, the state management unit 306 changes the state of Edge Relay 128 to the S2 state 606, and proceeds to step S1010 (step S1053).

  When it is determined that the determination condition of step S1052 is not satisfied, the state management unit 306 determines whether or not the state of the Edge Relay 128 is the S0 state 604 (step S1054).

  When it is determined that the determination condition of step S1054 is satisfied, the state management unit 306 changes the state of Edge Relay 128 to the S1 state 605 and proceeds to step S1010 (step S1055).

  When it is determined that the determination condition in step S1055 is not satisfied, the state management unit 306 determines whether or not the current Edge Relay 128 state is the S2 state 606 (step S1056).

  When it is determined that the determination condition of step 1056 is not satisfied, that is, when it is determined that the current Edge Relay 128 state is the S3 state 607, the state management unit 306 ends the process (step S1007).

  When it is determined that the determination condition of step S1056 is satisfied, the state management unit 306 determines whether or not the transition standby time has elapsed (step S1057). Note that the processing in step S1057 is the same as that in step 1014. That is, when the difference between the current time and the time of the variable “transition standby start time” is larger than the set “transition standby time”, it is determined that the transition standby time has elapsed.

  When it is determined that the transition waiting time has not elapsed, the state management unit 306 ends the process (step S1007).

  If it is determined that the transition waiting time has elapsed, the state management unit 306 proceeds to step S1010.

  If it is determined in step S1032 that the determination condition is satisfied, or if it is determined in step S1051 that the determination condition is satisfied, the state management unit 306 records the transfer stop start time and proceeds to step S1062 (step S1061). ). Specifically, the state management unit 306 stores the current time in the variable “transition standby start time”.

  The state management unit 306 sets the transfer stop state and ends the processing (steps S1062 and S1007). Specifically, the state management unit 306 sets a value indicating that the transfer is stopped in the variable “transfer stop state”.

  The outline of the state transition process in Edge Relay 128 described above is as follows.

  The state transition process in Edge Relay 128 is started when a transition instruction is received or a control frame is received.

  The state management unit 306 first determines the state of Edge Relay 128 based on the current state of Edge Relay 128, the content of the transition instruction, the state information included in the received control frame, and the elapsed time, and the determined state Change to

  Further, the state management unit 306 transfers a control frame for notifying the changed state to the bridge device 101. Furthermore, the state management unit 306 stops frame transfer by setting the transfer stop state, or restarts frame transfer by canceling the transfer stop state.

  When the transfer stop state is set, the state management unit 306 changes to the S2 state 606 if the current Edge Relay 128 state is the S3 state 607 after a predetermined time has elapsed (step S1021 is YES) (step S1024). In the case of a state other than the S3 state 607 (S1 state 605 or S5 state 609), the state is changed to the S3 state 607 (step S1025). Thereafter, the state management unit 306 cancels the transfer stop state (steps S1022A and 1022B).

  When the control frame including the B0 state 703 is received (step S1003 is YES) and the Edge Relay 128 is in the S0 state 604 (step S1013 is NO), the state management unit 306 ends the process.

  When a control frame including the B0 state 703 is received (step S1003 is YES) and the Edge Relay 128 is in the S1 state 605 (step S1013 is YES), after a predetermined time has elapsed (step S1014 is YES), S2 The status is changed to 606 (step S1012), and the transition standby time measurement is reset (step S1010). Thereafter, the state management unit 306 transmits a control frame based on the changed state, and ends the process (steps S1006 and S1007).

  When the control frame including the B0 state 703 is received (YES in step S1003) and the Edge Relay 128 state is the S3 state 607 or the S5 state 609, the state management unit 306 changes the state (step S1009 or step S1009). S1012), the transition standby time measurement is reset (step S1010). Thereafter, the state management unit 306 transmits a control frame based on the changed state, and ends the process (steps S1006 and S1007).

  If the control frame including the B0 state 703 is received (YES in step S1003) and the Edge Relay 128 state corresponds to either the S2 state 606 or the S4 state 608, the state management unit 306 enters the S0 state 604. It changes (step S1005), transmits a control frame based on the state after the change, and ends the process (steps S1006 and S1007).

  Even when a control frame including the B3 state 706 is received (NO in step S1041), the same processing as when the control frame is received in the B0 state 703 is executed, but the branch A and the branch B described below are different. .

  In branch A, when the state of Edge Relay 128 is S1 state 605 or S5 state 609 (YES in step S1051), frame transfer is stopped (step S1062).

  On the other hand, in the branch B, when the state of Edge Relay 128 is the S2 state 606 and a certain time has passed (YES in step S1057), the state is not changed and remains in the S2 state 606. The branch A will be described later together with the case where step S1032 is NO.

  Regarding the branch B, the state management unit 306 gives the transition to the VEPA mode 602 to failsafe by giving up the transition to the VEPA mode 602 after the fixed relay 128 is in the S1 state 605 and a certain time has elapsed (YES in step S1014). Therefore, the state is changed to the S2 state 606, and a transition to the VEB mode 601 is attempted.

  This is because Edge Relay 128 requested the bridge device 101 to transition to the VEPA mode 602, but the mode transition was not successful and the operation was continued in the VEB mode 601, for some reason, the control frame was buffered. This is to reduce the possibility of a situation in which the Edge Relay 128 operates in the VEB mode 601 while the bridge device 101 operates in the RR mode 702 due to successful mode transition after a delay.

  In the combination of modes of each device described above, there is a possibility that the frame transmitted from Edge Relay 128 may return to Edge Relay 128, so that the frames overlap, port learning fails, and frame duplication is performed indefinitely. As a result, the number of frames may increase and control may be lost. On the other hand, when Edge Relay 128 operates in VEPA mode 602 and bridge device 101 operates in SW mode 701, a frame transmitted by Edge Relay 128 may be lost, but this is a dangerous state compared to the combination of modes described above. It will not be.

  In the present embodiment, the state of the Edge Relay 128 is changed after the transition standby time has elapsed because a transition instruction to the bridge device 101 described later is executed in preference to a transition instruction to the Edge Relay 128. However, the present invention is not limited to this execution order.

  For example, the configuration may be changed so that the bridge device 101 changes the state after the transition waiting time elapses, and the state transition execution order may be reversed by omitting the state transition configuration described above from Edge Relay 128. With this configuration, the configuration of Edge Relay 128 can be simplified. Further, both the Edge Relay 128 and the bridge device 101 may be configured to execute the state transition process after the transition standby time has elapsed. Thereby, failure of state transition can be reduced.

  The cause of the state transition during the transition waiting time may be a loss due to an error caused by a cosmic ray of the control frame, a failure of receiving or processing failure of the control frame by the Edge Relay 128 or the bridge device 101, or unexpected processing. It can be considered that it takes time.

  On the other hand, when a control frame including the B2 state 705 is received or an instruction to transition to the VEPA mode 602 is received (YES in step S1041), and the Edge Relay 128 state is the S1 state 605 or the S3 state 607 (step S1042 is NO), the state of Edge Relay 128 remains as it is. Also, when the instruction to transition to the VEPA mode 602 is received (YES in step S1041) and the state of Edge Relay 128 is in the S5 state 609 (NO in step S 1045), the state of Edge Relay 128 remains unchanged.

  When the instruction to transition to the VEPA mode 602 is received and the state of Edge Relay 128 is the S4 state 608 (YES in step S1045), the state management unit 306 changes to the S5 state 609 (step S1046) and resets the time measurement. (Step S1010), and a control frame is transmitted based on the changed state (Step S1006).

  In other cases (YES in step S1043), the state management unit 306 changes to the S1 state 605 (step S1044), resets the time measurement (step S1010), and controls the control frame based on the changed state. Is transmitted (step S1006).

  When a control frame including the B1 state 704 is received or an instruction to transition to the VEB mode 601 is received (step S1031 is YES), the operation is the same as when the step S1041 is YES, but the S3 state 607 (Step S1032 is YES), the state management unit 306 is different in that the transfer is stopped (step S1062).

  When the transition to the VEPA mode 602 is completed (step S1051 is YES), or when the transition from the VEPA mode 602 to the VEB mode 601 is started (step S1032 is YES), the state management unit 306 waits for reception. The frame transfer is stopped until the time elapses.

  When a frame is received while frame transfer is stopped, the state management unit 306 first processes the frame received from the UPLINK port connected to the bridge apparatus 101, accumulates the frame received from a port other than the UPLINK, and then Process with. By this operation, it is possible to maintain the frame order when the state (transition) between the VEPA mode 602 and the TRAN mode 603 is switched, that is, at the moment when the device (position) for performing the switching process is switched between the bridge device 101 and the Edge Relay 128.

  Note that the reception standby time is a time that covers the round trip between the Edge Relay 128 and the bridge device 101 and the processing time of the Edge Relay 128 and the bridge device 101, but is generally several microseconds to several milliseconds or less. There is no substantial impact on communication users due to communication interruptions due to suspension.

  In addition, frames that are looped back from the bridge device 101 while the transfer is stopped and received at the UPLINK port are transferred based on the operation of the VEPA mode 602 at the time of transition from the VEPA mode 602 to the TRAN mode 603, so that frame discard is suppressed. In the transition from the TRAN mode 603 to the VEPA mode 602, the frame is discarded based on the operation of the TRAN mode 603, so that duplication of frames can be prevented, and each is processed correctly.

(Operation in Bridge Device 101)
Next, processing executed by the bridge device 101 will be described. In the following description, the variable name represents a value stored in the variable.

  FIG. 11A and FIG. 11B are flowcharts illustrating processing executed by the bridge device 101 according to the first embodiment of this invention.

  When the bridge device 101 is activated, initialization of the program such as confirmation of hardware and settings is executed, and then the start state is entered (step S1101).

  Note that the processing shown in FIGS. 11A and 11B is executed for each port. In the present embodiment, the state management unit 306 manages the state of each port, and executes the processing described below for each port. However, the present invention is not limited to this. For example, the state management unit 306 or the overall control unit 120 may be prepared for each port or for each group in which a plurality of ports are grouped, and processing may be performed in parallel, or only a part of the processing may be performed. Processing may be executed in parallel for each group or for each group.

  The state management unit 306 manages the variable “RRCAP” and the variable “RRCTR” for each port. Based on the combination of the values of the variables, each port is in the B0 state 703, the B1 state 704, the B2 state 705, and the B3 state. Which state of 706 is managed. Further, the state management unit 306 changes each state when state transition is necessary.

  Further, the state management unit 306 manages the variable “RRSTAT” and the variable “RRREQ” for each port, and based on the combination of the variables, the state of the Edge Relay 128 connected to the port is the S0 state 604, the S1 state 605, It manages which of the S2 state 606, the S3 state 607, the S4 state 608, and the S5 state 609.

  Here, the state management unit 306 sets the B0 state 703 in initialization. In addition, the state management unit 306 sets the state of the Edge Relay 128 connected to the port of the bridge device 101 to the S0 state 604 during initialization.

  When entering the start state, the state management unit 306 of the bridge device 101 first determines whether a transition instruction has been received (step S1102). Here, the transition instruction is either a transition instruction to the SW mode 701 or a transition instruction to the RR mode 702, and is given by setting or externally.

  In step 1102, it is assumed that it is determined that the transition instruction is received only once every time the transition instruction is received. That is, the determination result is “YES” only once for one transition instruction.

  When it is determined that the transition instruction has been received, the state management unit 306 records information regarding the transition instruction, and proceeds to step S1104 (step S1103). Specifically, a variable “transition instruction state” indicating that the transition instruction has been received and whether the transition instruction is a transition instruction to the SW mode 701 or a transition instruction to the RR mode 702 is recorded. .

  The state management unit 306 executes port state transition processing in the bridge device 101, and proceeds to step 1105 (step S1104). Details of the port state transition process in the bridge device 101 will be described later.

  After the state transition process ends, the state management unit 306 refers to the variable “transition instruction state” and determines whether or not a transition instruction is recorded (step S1105). When a value indicating a transition instruction to the SW mode 701 or a transition instruction to the RR mode 702 is stored in the variable “transition instruction state”, it is determined that the transition instruction is recorded.

  If it is determined that no transition instruction is recorded, the state management unit 306 returns to step S1102 and executes the same processing.

  If it is determined in step S1102 that a transition instruction has not been received, the state management unit 306 determines whether the port has received a frame based on the information transmitted from the frame classification / information extraction unit 311 ( Step S1106).

  If it is determined that the port has not received a frame, the state management unit 306 returns to step S1102 and executes the same processing.

  When it is determined that the port is receiving a frame, the state management unit 306 determines whether the port has received a control frame based on the information transmitted from the frame classification / information extraction unit 311 ( Step S1107).

  When it is determined that the port has not received the control frame, the state management unit 306 proceeds to step S1121.

  When it is determined that the port has received the control frame, the state management unit 306 acquires the contents of the control frame from the control frame processing unit 307, sets values in the variable “RRSTAT” and the variable “RRREQ”, and performs the step The process proceeds to S1104.

  When it is determined in step S1105 that the transition instruction is recorded, the state management unit 306 refers to the variable “transition instruction state”, the variable “RRCAP”, and the variable “RRCTR”, and the transition instruction to the SW mode 701 is issued. It is determined whether or not the recorded state of the port of the bridge device 101 is the B0 state 703 (step S1108).

  If it is determined that the determination condition of step S1108 is satisfied, the state management unit 306 responds to the accepted transition instruction that the process has been successful, and the process proceeds to step S1110 (step S1109). As a response method, for example, a method of outputting information indicating success through an input / output device and responding by transmitting a frame including information indicating success through a port is conceivable. In addition, the information may be notified together with the state notification by the control frame. Note that this process may be omitted when a response to the transition instruction is not required.

  The state management unit 306 deletes the variable “transition instruction state”, returns to step S1102, and executes the same processing (step S1110). Here, as a method of deleting the variable “transition instruction state”, for example, a value different from the value indicating the transition instruction is substituted into the variable. Note that in the start state, the variable “transition instruction state” is in a deleted state.

  When it is determined in step S1108 that the determination condition in step S1108 is not satisfied, the state management unit 306 refers to the variable “transition instruction state”, the variable “RRCAP”, and the variable “RRCTR”, and transitions to the RR mode 702. It is determined whether the instruction is recorded and the current port state of the bridge device 101 is the B3 state 706 (step S1111).

  If it is determined that the determination condition of step S1111 is not satisfied, the state management unit 306 returns to step S1102 and executes the same processing. If it is determined that the determination condition of step S1111 is satisfied, the state management unit 306 proceeds to step S1109.

  When it is determined in step S1107 that the port has not received the control frame, the state management unit 306 instructs the port learning unit 310 to execute port learning (step S1121). The port learning unit 310 that has received the instruction performs port learning using the transmission source MAC address and VLAN ID of the target frame.

  Next, the state management unit 306 instructs the delivery port determination unit 309 to search for a delivery port, and proceeds to step S1123 (step S1122). The delivery port determination unit 309 that has received the instruction executes the following processing.

  First, the delivery port determination unit 309 searches for a learned port by making an inquiry to the port learning unit 310 based on the destination MAC address and VLAN ID of the target frame.

  When learned ports are found, the delivery port determining unit 309 decides the ports (one or more) as delivery ports, and when no learned ports are found, decides all ports as delivery ports.

  Next, the state management unit 306 refers to the variable “RRCAP” and the variable “RRCTR” to determine whether the current port mode of the bridge device 101 is the RR mode 702 (B1 state 704 or B3 state 706). Determination is made (step S1123).

  When it is determined that the current port mode of the bridge device 101 is the RR mode 702, the state management unit 306 instructs the delivery port determination unit 309 to deliver the frame to the delivery port (step S1124).

  The state management unit 306 inquires of the delivery port determination unit 309 and determines whether there is a frame delivered to each port (step S1125). If it is determined that there is no frame delivered to each port, the state management unit 306 returns to step S1102 and executes the same processing.

  When it is determined that there is a frame delivered to each port, the state management unit 306 instructs the transmission / reception control unit 313 to transmit the delivered frame, and then returns to step S1102 to execute similar processing (step S1102). S1126).

  When it is determined in step S1123 that the current mode of the bridge device 101 is not the RR mode 702, the state management unit 306 instructs to exclude the delivery port and proceeds to step S1124 (step S1127). The delivery port determination unit 309 that has received the instruction excludes the reception port of the target frame transmitted from the frame classification / information extraction unit 311 from among the delivery ports determined in step S1122, and newly distributes the remaining ports. Determine as a port.

  The outline of the processing executed by the bridge device 101 described above is as follows.

  First, the bridge device 101 executes initialization. If a transition instruction is received (YES in step S1102), the bridge device 101 executes a port state transition process (step S1104). When the processing result is output (step S1108, step S1111), the bridge device 101 returns a response (step S1109) and returns to the beginning (step S1102).

  If a transition instruction has not been received and a control frame has been received (YES in step S1107), the bridge device 101 executes a port state transition process (step S1104), and then returns to the beginning (step S1102).

  If a transition instruction has not been received and a frame other than the control frame has been received (NO in step S1007), the bridge device 101 transmits a frame after executing frame distribution processing (steps S1121 to 1124 and step S1127). (Step S1126).

  In the frame delivery process, when the mode of the bridge device 101 is the RR mode 702, the bridge device 101 does not exclude the reception port from the delivery port. The processing described above is executed for each port.

(Port state transition processing)
Next, port state transition processing in the bridge device 101 will be described.

  12A, 12B, 12C, and 12D are flowcharts illustrating the port state transition process in the bridge device 101 according to the first embodiment of this invention.

  The acquisition of the state of the bridge device 101 and the reception of the control frame including the state information of Edge Relay 128 have been described with reference to FIG.

  The change of the state of the bridge device 101 is realized by changing the values of the variable “RRCAP” and the variable “RRCTR”. Therefore, when the state of the bridge device 101 is changed, it means that the values of the variable “RRCAP” and the variable “RRCTR” are changed.

  The port state transition process is executed when a transition instruction is accepted or when a control frame is received. In the following description, the expression “a control frame including state information has been received” is an opportunity for the port state transition process. It is assumed that state information (S0 state 604, S1 state 605, S2 state 606, S3 state 607, S4 state 608 or S5 state 609) is included in the control frame. Further, the state management unit 306 can update the variable “RRSTAT” and the variable “RRREQ” according to the control frame, and obtain the state information of the Edge Relay 128 with reference to the variable “RRSTAT” and the variable “RRREQ”.

  When the port state transition process in the bridge device 101 is started (step S1201), the state management unit 306 determines whether or not the state of the bridge device 101 is the B0 state 703 (step S1202).

  If it is determined that the determination condition of step S1202 is not satisfied, the state management unit 306 proceeds to step S1211.

  When it is determined that the determination condition of step S1202 is satisfied, the state management unit 306 refers to the variable “transition instruction state” and determines whether a transition instruction to the RR mode 702 has been received (step S1203).

  If it is determined that an instruction to transition to the RR mode 702 has been received, the state management unit 306 changes the state of the bridge device 101 to the B2 state 705 and proceeds to step 1205 (step S1204).

  The state management unit 306 instructs the control frame generation unit 308 to generate a control frame including the current state information of the bridge device 101, and ends the processing (steps S1205 and S1206). Receiving the instruction, the control frame generation unit 308 generates a control frame and transmits the control frame to the Edge Relay 128 connected to the processing target port.

  If it is determined in step S1203 that a transition instruction to the RR mode 702 has not been accepted, the state management unit 306 refers to the variable “transition instruction state” and determines whether or not a transition instruction to the SW mode 701 has been accepted. (Step S1207).

  If it is determined that an instruction to transition to the SW mode 701 has been received, the state management unit 306 ends the process (step S1206).

  When it is determined that the instruction to transition to the SW mode 701 is not received, the state management unit 306 determines whether a control frame including the S1 state 605 or the S5 state 609 has been received (step S1208).

  If it is determined that the determination condition of step S1208 is not satisfied, the state management unit 306 proceeds to step S1210 without changing the state of the bridge device 101.

  When it is determined that the determination condition of step S1208 is satisfied, the state management unit 306 changes the state of the bridge device 101 to the B3 state 706 and proceeds to step S1210 (step S1209).

  The state management unit 306 determines whether a control frame including any of the S1 state 605, the S2 state 606, the S4 state 608, or the S5 state 609 has been received (step S1210).

  When it is determined that the determination condition of step S1210 is not satisfied, the state management unit 306 ends the process (step S1206). When it is determined that the determination condition of step S1210 is satisfied, the process proceeds to the state management unit 306 and step S1205.

  If it is determined in step S1202 that the determination condition in step S1202 is not satisfied, the state management unit 306 determines whether or not the state of the bridge device 101 is the B1 state 704 (step S1211).

  When it is determined that the determination condition of step S1211 is satisfied, the state management unit 306 refers to the variable “transition instruction state” and determines whether a transition instruction to the RR mode 702 has been received (step S1212).

  When it is determined that the determination condition of step S1212 is satisfied, the state management unit 306 changes the state of the bridge device 101 to the B3 state 706, and proceeds to step 1205 (step S1213).

  When it is determined that the determination condition of step S1212 is not satisfied, the state management unit 306 refers to the variable “transition instruction state” and determines whether or not a transition instruction to the SW mode 701 has been received (step S1214).

  When it is determined that the determination condition of step S1214 is satisfied, the state management unit 306 ends the process (step S1206).

  When it is determined that the determination condition in step S1214 is not satisfied, the state management unit 306 determines whether a control frame including any of the S0 state 604, the S2 state 606, or the S4 state 608 has been received (step S1215). ).

  If it is determined that the determination condition in step S1215 is not satisfied, the state management unit 306 proceeds to step S1210.

  When it is determined that the determination condition of step S1215 is satisfied, the state management unit 306 changes the state of the bridge device 101 to the B0 state 703 and proceeds to step S1210 (step S1216).

  In step S1211, when it is determined that the determination condition of step S1211 is not satisfied, the state management unit 306 determines whether or not the state of the bridge device 101 is the B2 state 705 (step S1221).

  When it is determined that the determination condition of step S1221 is satisfied, the state management unit 306 refers to the variable “transition instruction state” and determines whether or not a transition instruction to the SW mode 701 has been received (step S1222).

  When it is determined that the determination condition of step S1222 is satisfied, the state management unit 306 changes the state of the bridge device 101 to the B0 state 703, and proceeds to step 1205 (step S1223).

  When it is determined that the determination condition in step S1222 is not satisfied, the state management unit 306 determines whether the state management unit 306 has received a transition instruction to the RR mode 702 with reference to the variable “transition instruction state”. (Step S1224).

  When it is determined that the determination condition of step S1224 is satisfied, the state management unit 306 ends the process (step S1206).

  When it is determined that the determination condition of step S1224 is not satisfied, the state management unit 306 determines whether a control frame including any of the S1 state 605, the S3 state 607, or the S5 state 609 has been received (step S1225). ).

  If it is determined that the determination condition in step S1225 is not satisfied, the state management unit 306 proceeds to step S1210.

  When it is determined that the determination condition of step S1225 is satisfied, the state management unit 306 changes the state of the bridge device 101 to the B3 state 706, and proceeds to step S1210 (step S1226).

  If it is determined in step S1221 that the determination condition in step S1221 is not satisfied, that is, the state of the bridge device 101 is the B3 state, the state management unit 306 refers to the variable “transition instruction state” and switches to the SW mode 701. It is determined whether or not a transition instruction to is accepted (step S1231).

  When it is determined that the determination condition of step S1231 is satisfied, the state management unit 306 changes the state of the bridge device 101 to the B1 state 704, and proceeds to step S1205 (step S1232).

  When it is determined that the determination condition of step S1231 is not satisfied, the state management unit 306 refers to the variable “transition instruction state” and determines whether or not an instruction to transition to the RR mode 702 has been received (step S1233).

  When it is determined that the determination condition of step S1233 is satisfied, the state management unit 306 ends the process (step S1206).

  When it is determined that the determination condition of step S1233 is not satisfied, the state management unit 306 determines whether a control frame including the S2 state 606 or the S4 state 608 has been received (step S1234).

  If it is determined that the determination condition in step S1234 is not satisfied, the state management unit 306 proceeds to step S1210.

  When it is determined that the determination condition of step S1234 is satisfied, the state management unit 306 changes the state of the bridge device 101 to the B0 state 703 and proceeds to step S1210 (step S1235).

  The outline of the port state transition processing in the bridge device 101 described above is as follows.

  The port state transition process in the bridge device is started when a transition instruction is received or a control frame is received. First, the state management unit 306 determines the state of the bridge device 101 based on the current state of the bridge device 101, the content of the transition instruction, and the state information of Edge Relay 128 included in the received control frame. Change to the state. In addition, the state management unit 306 transfers a control frame for notifying the changed state.

  When the B0 state 703 and an instruction to transition to the RR mode 702 are received, the state management unit 306 changes the state of the bridge device 101 to the B2 state 705 (step S1204). When the B3 state 706 and an instruction to transition to the SW mode 701 are received, the state management unit 306 changes the state of the bridge device 101 to the B1 state 704 (step S1232).

  When a control frame including the S1 state 605 or S5 state 609 is received in the B0 state 703 (step S1208 is YES), when a transition instruction to the RR mode 702 is received (step S1212 is YES), Alternatively, when a control frame including any of the B2 state 705 and the S1 state 605, the S3 state 607, or the S5 state 609 is received (YES in step S1225), the state management unit 306 changes the state of the bridge device 101 to B3. Change to state 706.

  When B1 state 704 and S0 state 604, S2 state 606 or S4 state 608 are received (YES at step S1215), when B2 state 705 and an instruction to transition to SW mode 701 are received (YES at step S1222) When the control frame including the B3 state 706 and the S2 state 606 or the S4 state 608 is received (YES in step S1234), the state management unit 306 changes the state of the bridge device 101 to the B0 state 703. .

  When the state is changed by receiving a transition instruction or receiving a control frame including the S1 state 605, the S2 state 606, the S4 state 608 or the S5 state 609, the state management unit 306 notifies the changed state. A control frame for transmitting is transmitted (step S1205).

  Compared with the state transition process in Edge Relay 128 described in FIG. 10, the port state transition process in the bridge device 101 is simpler. This is because the number of states of Edge Relay 128 is six, whereas the number of states of bridge device 101 is four, and there is no processing associated with the passage of time and processing for stopping frame transfer.

  Next, an outline of an operation in a system including the Edge Relay 128 and the bridge device 101 will be described. Hereinafter, combinations of modes of the respective devices will be described.

(When Edge Relay 128 operates in the VEB mode 601 and the bridge device 101 operates in the SW mode 701)
Here, it is assumed that Edge Relay 128 operates in the VEB mode 601 (S0 state 604), and the bridge device 101 operates in the SW mode 701 (B0 state 703). In this case, the Edge Relay 128 and the bridge device 101 do not change their states even if they transmit and receive control frames.

  When a frame addressed to the virtual machine 130-2 is transmitted from the virtual machine 130-1, the Edge Relay 128 and the bridge device 101 are not performing port learning in the initial state. Therefore, Edge Relay 128 transfers frames to all ports except the receiving port, that is, the virtual machine 130-2 and the bridge device 101. Similarly, the bridge device 101 transfers frames to the server device 102-2 and the node device 104. To do.

  The virtual machine 130-2 receives the frame because the destination of the transferred frame is addressed to itself, and executes a predetermined process using the frame. On the other hand, the server apparatus 102-2 and the node apparatus 104 discard the frame because the destination of the transferred frame is not addressed to itself. Therefore, as a result, the frame is correctly transmitted to the virtual machine 130-2.

  At this time, the Edge Relay 128 and the bridge device 101 learn from which port the frame that includes the address of the virtual machine 130-1 as the transmission source address is received.

  Next, when a frame addressed to the virtual machine 130-1 is transmitted from the virtual machine 130-2, the Edge Relay 128 has learned the port of the address of the virtual machine 130-1 as a result of port learning. The frame is transferred only to the port to which 1 is connected. Further, the virtual machine 130-1 receives the frame and executes a predetermined process using the frame.

  At this time, the Edge Relay 128 and the bridge device 101 learn from which port the frame that includes the address of the virtual machine 130-2 in the source address is received.

  Hereinafter, it is assumed that the Edge Relay 128 and the bridge device 101 have learned the virtual machine 130-1 and the virtual machine 130-2 according to the same procedure.

  Similarly, the frame addressed to the virtual machine 130-1 transmitted from the server apparatus 102-2 or the node apparatus 104 is transmitted to the virtual machine 130-1 via the bridge apparatus 101 and the Edge Relay 128 in this order.

  The transmission path of frames transmitted and received between the virtual machine 130-1 and the virtual machine 130-2 changes depending on the state and mode of the Edge Relay 128 and the bridge device 101, but the transmission paths of other frames do not change. Will be omitted in the description of.

  Currently, Edge Relay 128 operates in the VEB mode 601 (S0 state 604), and the bridge device 101 operates in the SW mode 701 (B0 state 703).

  When the frame addressed to the virtual machine 130-2 is transmitted from the virtual machine 130-1, the Edge Relay 128 executes the switching process of the frame and transfers the frame to the virtual machine 130-2. Frames are never transferred.

  When a broadcast frame is transmitted from the virtual machine 130-1, the frame is transferred from the Edge Relay 128 to the virtual machine 130-2 and the bridge device 101. The bridge device 101 has all ports except the reception port, that is, the server device. The frame is transferred to 102-2 and the node device 104. Accordingly, since the frames are transferred to the virtual machine 130-2, the server apparatus 102-2, and the node apparatus 104, broadcast communication can be performed correctly.

(After accepting the transition instruction to VEPA mode 602, Edge Relay 128 operates in TRAN mode 603 and bridge device 101 operates in SW mode 701)
Next, when the Edge Relay 128 receives a transition instruction to the VEPA mode 602, the state is changed to the S1 state 605 by executing a state transition process. Accordingly, Edge Relay 128 operates in the TRAN mode 603. Further, Edge Relay 128 transmits a control frame including the S1 state 605 to the bridge device 101.

  At this time, Edge Relay 128 operates in the TRAN mode 603 (S1 state 605), and the bridge device 101 operates in the SW mode 701 (B0 state 703).

  When a frame addressed to the virtual machine 130-2 is transmitted from the virtual machine 130-1, the Edge Relay 128 executes the switching process of the frame and transfers the frame to the virtual machine 130-2. Frames are never transferred.

  When a broadcast frame is transmitted from the virtual machine 130-2, the frame is transferred from the Edge Relay 128 to the virtual machine 130-2 and the bridge device 101. The bridge device 101 has all ports except the reception port, that is, the server device. The frame is transferred to 102-2 and the node device 104. Accordingly, since the frame is transferred to each of the virtual machine 130-2, the server apparatus 102-2, and the node apparatus 104, broadcast communication can be performed correctly.

(When Edge Relay 128 operates in TRAN mode 603 and bridge device 101 operates in RR mode 702)
When the bridge device 101 receives the control frame including the S1 state 605, the bridge device 101 changes the state to the B3 state 706 by executing the port state transition process, and further transmits the control frame including the B3 state 706 to the Edge Relay 128. At this time, Edge Relay 128 operates in the TRAN mode 603 (S1 state 605), and the bridge device 101 operates in the RR mode 702 (B3 state 706).

  When the frame addressed to the virtual machine 130-2 is transmitted from the virtual machine 130-1, the Edge Relay 128 executes the switching process of the frame and transfers the frame to the virtual machine 130. Never forwarded.

  When a broadcast frame is transmitted from the virtual machine 130-1, the frame is transferred from the Edge Relay 128 to the virtual machine 130-2 and the bridge apparatus 101. The bridge apparatus 101 operating in the RR mode 702 includes all reception ports. The frame is transferred to the ports, that is, Edge Relay 128, server apparatus 102-2, and node apparatus 104.

  On the other hand, since Edge Relay 128 operating in the TRAN mode 603 has an entry indicating a port other than the reception port in the transfer port management table 124, information on the transmission source (virtual machine 130-1) of the frame transferred from the bridge device 101 exists. Is learned (step S913 is YES). Therefore, Edge Relay 128 discards the frame.

  In the present invention, by introducing the TRAN mode 603, as a result, the frame is transferred to each of the virtual machine 130-2, the server apparatus 102-2, and the node apparatus 104, so that broadcast communication can be performed correctly.

(When Edge Relay 128 operates in VEPA mode 602 and bridge device 101 operates in RR mode 702)
When the Edge Relay 128 receives the control frame including the B3 state 706, the Edge Relay 128 executes the state transition process to continue the transfer of the frame received by the UPLINK port to which the bridge device 101 is connected (YES in Step S815). Transfer of frames received by ports other than the port is stopped during the reception waiting time (step S1062), and the frames are accumulated (step S824).

  The Edge Relay 128 starts operation in the VEPA mode 602 by changing the state to the S3 state 607, then restarts frame transfer (step S1022B), and executes transfer processing in order from the accumulated frame (step S821). . As a result, frames received by Edge Relay 128 while transfer is stopped are transferred in the correct order. The Edge Relay 128 transmits a control frame including the S3 state 607 to the bridge device 101.

  At this time, Edge Relay 128 operates in the TRAN mode 603 in the first half but is in a transfer stop state, and operates in the VEPA mode 602 (S3 state 607) in the second half. On the other hand, the bridge device 101 operates in the RR mode 702 (B3 state 706) in both the first half and the second half.

  Therefore, when a frame addressed to the virtual machine 130-2 is transmitted from the virtual machine 130-1, the frame is not transferred to the bridge device 101 because the frame is accumulated in the Edge Relay 128 in the first half.

  In the second half, the switching process between the frame accumulated by Edge Relay 128 and the newly received frame is executed in order. When a frame addressed to the virtual machine 130-2 is transmitted from the virtual machine 130-1, the frame is received from a port other than the port (UPLINK port) to which the bridge device 101 is connected (NO in step S909). The frame is transferred to the bridge device 101.

  The bridge device 101 executes a switching process of the frame transferred from the Edge Relay 128. At this time, since the bridge device 101 has learned the destination of the virtual machine 130-2, the bridge device 101 transfers the frame to the port to which the Edge Relay 128 is connected.

  The Edge Relay 128 transfers the frame to the virtual machine 130-2 in order to receive the frame from the port (UPLINK port) to which the bridge device 101 is connected (YES in Step S909). The virtual machine 130-2 receives the frame and executes a predetermined process using the frame.

  That is, frames transmitted and received between the bridge apparatus 101 and the virtual machine 130-1 as destinations are transferred to the bridge apparatus 101 via the EdgeRelay 128, the switching process is executed by the bridge apparatus 101, and the Edge Relay 128 is further processed. Is transmitted to the destination via.

  Even when a broadcast frame is transmitted from the virtual machine 130-2, the frame is transmitted to the virtual machine 130-1 for each frame through the same path, and Edge Relay 128 is transmitted to the server apparatus 102-1 and the node apparatus 104. A frame is transmitted frame by frame from the bridge device 101 via the above.

(Operation while Edge Relay 128 is transitioning to VEB mode 601)
Upon receiving an instruction to transition to the VEPA mode 602, Edge Relay 128 executes state transition processing and continues to transfer the frame received from the UPLINK port to which the bridge device 101 is connected (YES in step S815). The transfer of the frame received from the other port is stopped during the reception waiting time (step S1062), and the frame is accumulated (step S824).

  The Edge Relay 128 starts operation in the TRAN mode 603 by changing to the S2 state 606, resumes frame transfer (steps S1022A and S1022B), and executes transfer processing in order from the accumulated frames (step S820). . As a result, the frames received by Edge Relay 128 when the transfer is stopped are transferred in the correct order.

  Further, Edge Relay 128 transmits a control frame including the S2 state 606 to the bridge device 101.

  At this time, the edge relay 128 operates in the VEPA mode 602 in the first half, but is in a transfer stop state, and operates in the TRAN mode 603 in the second half to resume frame transfer. On the other hand, the bridge device 101 operates in the RR mode 702 in both the first half and the second half.

  Therefore, when a frame addressed to the virtual machine 130-2 is transmitted from the virtual machine 130-1, the frame is accumulated in the Edge Relay 128 in the first half, and the frame accumulated in the Edge Relay 128 and the switching process of the frame are sequentially executed in the second half. Since the frame is transferred to the virtual machine 130-2, the frame is not transferred to the bridge device 101.

  When a broadcast frame is transmitted from the virtual machine 130-1, the frame is transferred from the Edge Relay 128 to the virtual machine 130-2 and the bridge device 101 after the transfer is resumed. The bridge device 101 operating in the RR mode 702 transfers the frame to all ports including the reception port, that is, the Edge Relay 128, the server device 102-2, and the node device 104.

  Edge Relay 128 operating in the TRAN mode 603 learns information on the transmission source (virtual machine 130-2) of the frame transferred from the bridge device 101 because an entry indicating a port other than the reception port exists in the transfer port management table 124. It is determined that it has been completed (step S913 is YES). Therefore, Edge Relay 128 discards the frame.

  In the present invention, by introducing the TRAN mode 603, the frame is transferred to each of the virtual machine 130-2, the server apparatus 102-2, and the node apparatus 104 as a result, so that broadcast communication can be performed correctly.

  When the bridge device 101 receives the control frame including the S2 state 606, the bridge device 101 changes the state to the B0 state 703 by executing the port state transition process, and transmits the control frame including the B0 state 703 to the Edge Relay 128. At this time, Edge Relay 128 operates in the TRAN mode 603 (S2 state 606), and the bridge device 101 operates in the SW mode 701 (B0 state 703). Since the operation in the combination of the modes has been described above, the description thereof will be omitted.

  Upon receiving the control frame including the B0 state 703, the Edge Relay 128 changes the state to the S0 state 604 by executing the state transition process, starts operation in the VEB mode 601, and also receives the control frame including the S0 state 604. Transmit to the bridge device 101. At this time, Edge Relay 128 operates in the VEB mode 601 (S0 state 604), and the bridge device 101 operates in the SW mode 701 (B0 state 703). Since the operation in the combination of the modes has been described above, the description thereof will be omitted.

(Description of mode transition)
Through the procedure described above, Edge Relay 128 suspends frame transfer from VEB mode 601 through TRAN mode 603, then transitions to VEPA mode 602, and further suspends frame transfer before VEPA mode 602. Transitions to VEB mode 601 through TRAN mode 603.

  Corresponding to the transition of the Edge Relay 128 mode, the bridge device 101 transitions from the SW mode 701 to the RR mode 702, and further transitions from the RR mode 702 to the SW mode 701.

  A device that performs switching processing of frames transmitted and received between the bridge device 101 and the virtual machine 130-1 continues communication from the Edge Relay 128 to the Bridge device 101 and from the Bridge device 101 to the Edge Relay 128 according to the mode change. And dynamically change.

  The combination of Edge Relay 128 and the mode of the bridge device 101 is any one of the VEB mode 601 and the SW mode 701, the TRAN mode 603 and the SW mode 701, the TRAN mode 603 and the RR mode 702, and the VEPA mode 602 and the RR mode 702. The operation in each combination is as described above.

  The frame that is temporarily stopped when the mode is changed between the VEPA mode 602 and the TRAN mode 603 is transferred from the Edge Relay 128 to the bridge device 101 operating in the RR mode 702, and then transmitted from the bridge device 101 to the Edge Relay 128. This is to prevent the frame and the frame transferred by the Edge Relay 128 operating in the TRAN mode 603 from being duplicated.

(Trigger for transition instructions)
In the present invention, the mode relay instruction in Edge Relay 128 and the bridge device 101 which is one of the triggers of state transition is instructed from the user or the administrator, but the present invention is not limited to this.

  For example, by setting a threshold value in Edge Relay 128 or the bridge device 101 and issuing a transition instruction when the CPU usage rate or the memory usage amount of the server device 102 or the bridge device 101 exceeds the threshold value, the server device 102 or the bridge device The apparatus for executing the switching process may be changed in accordance with the load fluctuation of 101.

  Further, for example, by setting a time in the Edge Relay 128 or the bridge device 101 and issuing a transition instruction when the set time is reached, the device that executes the switching process may be changed every time.

  As exemplified above, in the present invention, the transition instruction may be given to either Edge Relay 128 or the bridge device 101. For example, a network administrator may give a transition instruction to the bridge device 101 to change a device that executes a switching process in accordance with the convenience of network management such as a use schedule or monitoring of the network device. For example, server management A person may give a transition instruction to Edge Relay 128 and change a device that executes switching processing according to network requirements such as latency required by the server user.

(Connection with devices other than this embodiment)
Here, operations when Edge Relay 128 and another bridge device (hereinafter referred to as another bridge device) are connected, and when bridge device 101 and another bridge device are connected will be described.

  Regarding the connection between Edge Relay 128 and another bridge device, when Edge Relay 128 operates in TRAN mode 603 and does not receive a control frame for a certain period of time, it can be handled by adding a process for transitioning the state to S0 state 604.

  First, a case where the other bridge device does not support IEEE 802.1Qbg, that is, does not transmit a control frame will be described.

  When Edge Relay 128 and another bridge device are connected, Edge Relay 128 operates in TRAN mode 603 in the initial state. If the virtual machine is not moved, communication is normally performed even in the TRAN mode 603. In addition, since the control frame is not received for a certain period of time and the state transits to the S0 state 604 and operates in the VEB mode 601, the communication is normally performed.

  When transition to the VEPA mode 602 is instructed, the Edge Relay 128 temporarily transitions to the TRAN mode 603, but similarly transitions to the VEB mode 601. Further, when the bridge device 101 of the present invention is connected to another bridge device (operating as Edge Relay), it is in the B0 state 703 in the initial state, and thus operates in the SW mode 701 and communication is performed normally. Even when a transition instruction to the RR mode 702 is issued, the state transitions to the B2 state 705, but the bridge device 101 operates in the SW mode 701, so that communication is performed normally.

  Next, the operation when the other bridge device is compliant with IEEE 802.1Qbg will be described.

  IEEE 802.1Qbg stipulates that the EVB Bridge's Reflective Relay operation is valid only when RRCAP is “1” and RRREQ is “1”.

  If Edge Relay 128 is connected to another bridge device conforming to IEEE 802.1Qbg, and the other bridge device does not have the Reflective Relay function, only the control frame including the B0 state 703 is received, so Edge Relay 128 does not receive the control frame. Sometimes it operates in TRAN mode 603, and when it receives a control frame, it operates in VEB mode 601. Therefore, communication is performed normally. The same applies when a transition to the VEPA mode 602 is instructed.

  When the other bridge device has a reactive relay function, Edge Relay 128 receives a control frame including B2 state 705 or B3 state 706. In this case, if the control frame including the B2 state 705 received by the Edge Relay 128 is replaced with the control frame including the B0 state 703, the operation is performed including the mode transition instruction to the Edge Relay 128.

  On the other hand, when the bridge device 101 of the present invention is connected to another bridge device (operating as Edge Relay) conforming to IEEE 802.1Qbg, if the B0 state 703 is replaced with the B2 state 705, the bridge device 101 is transferred to. Operates normally except for transition instructions. The mode transition instruction to the bridge device 101 may fail because the behavior of other bridge devices cannot be completely controlled, and the transition may not be completed. Further, since the operation during the transition is not defined in IEEE 802.1Qbg, there is a possibility that communication in other bridge devices is not normally performed.

  Therefore, when Edge Relay 128 (including the slight changes described above) in the present embodiment is connected to another bridge device, and the other bridge device has a Reflective Relay function compatible with IEEE 802.1Qbg, include even a transition instruction to Edge Relay 128. In other cases, it operates except for a transition instruction. Further, communication is normally performed even when a transition instruction is issued. In addition, when the bridge device 101 (including the slight changes described above) in this embodiment is connected to another bridge device (operating as Edge Relay), the bridge device 101 operates except for an instruction to transition to Edge Relay 128, and communication is normally performed. To do.

  According to the first embodiment, it is possible to change a device that dynamically executes a switching process while continuing communication between the Edge Relay 128 and the bridge device 101. In addition, since the control frame required for the above-mentioned change is based on the IEEE 802.1Qbg standard, when connected to another bridge device, it operates normally except for the mode transition instruction, and the communication is performed. Can also be done normally.

  Furthermore, when Edge Relay 128 compliant with IEEE 802.1Qbg is connected to a bridge device having a Reflective Relay function, operation is possible including a mode transition instruction to Edge Relay 128.

[Second Embodiment]
In the first embodiment, Edge Relay 128 is a program that operates on the server apparatus 102. However, as described with reference to FIG. 3, since the software configuration of the Edge Relay 128 and the bridge device 101 is the same, the Bridge Device 101 can include the function of the Edge Relay 128. The second embodiment of the present invention is different from the first embodiment in that an edge relay 128 is included in the bridge device 101.

  Hereinafter, the second embodiment will be described focusing on the differences from the first embodiment.

  It is a block diagram explaining the logical structure of the computer system in the 1st Embodiment of this invention.

(System configuration)
FIG. 13 is a block diagram illustrating a logical configuration of a computer system according to the second embodiment of this invention.

  Note that the configurations of the server apparatus 102, the bridge apparatus 1301, and the Edge Relay 1302 are the same as those in the first embodiment, and a description thereof will be omitted.

  13, the bridge device 1301 has the same configuration as the bridge device 101, the server device 1303-1, the server device 1303-3, and the server device 1303-3 have the same configuration as the server device 102, and the node The device 1306 has the same configuration as the node device 104. The cable 1307-1, the cable 1307-2, the cable 1308-1, the cable 1308-2, and the cable 1311 have the same configuration as the cable 105.

  In FIG. 13, Edge Relay 1302 indicates the bridge device 101 in which Edge Relay 128 is executed.

  Each of the server device 1303-1, the server device 1303-3, and the server device 1303-3 is a network node having an input / output port compliant with Ethernet. The processes executed by the Edge Relay 1302 and the bridge device 1301 are the same as those of the Edge Relay 128 and the bridge device 101 in the first embodiment, and thus description thereof is omitted.

  According to the second embodiment, as in the first embodiment, the device that dynamically executes the switching process can be changed between the Edge Relay 1302 and the bridge device 1301 while continuing communication. Furthermore, since Edge Relay 1302 is executed on a device other than the server device 1303, even a computer that does not have a virtualization function can dynamically change the device that executes the switching process.

[Third Embodiment]
In the present invention, the Edge Relay 128 and the bridge device 101 may be realized by using a device or a program having both functions. In the third embodiment, a case where functions are concentrated in the bridge device 101 will be described as an example.

  The hardware configuration and the logical configuration in the third embodiment are the same as those in the first embodiment or the second embodiment, and are omitted. Hereinafter, the operation of the bridge device 101 according to the third embodiment will be described.

  The operation of the bridge device 101 described with reference to FIGS. 11A and 11B is the same as the operation in the VEB mode 601 of the Edge Relay 128 described with reference to FIGS. 8A and 8B, except for the processing related to the transfer stop state in FIGS. 8A and 8B. It is.

  This is because the basic operations of the bridge device 101 and the Edge Relay 128 are the received frame transfer process (Step S816, Step S820 to Step S824, Step S1121 to Step S1127), the received transition instruction or This is for executing state change processing according to the received control frame (steps S805 to S809, steps S1104 to S1105, and steps S1108 to S1111).

  In the frame transfer process, the processing in step S1127 is not executed in the RR mode 702. In the state change process, the contents of the state transition process (step S804) and the port state transition process (step S1104) are different. There is a big difference.

  However, the difference in the frame transfer process is simply a conditional branch, and the difference in the state change process is that the state transition process (step S804) is the entire process while the port state transition process (step S1104) is performed for each port. Therefore, the operation of the bridge device 101 and the operation of Edge Relay 128 can be realized and coexisted in the same device. For example, each port of the Edge Relay 128 can be changed to operate at the port of the bridge device 101 except for a port operating as UPLINK in the VEPA mode 602.

  Specifically, in FIG. 9, instead of step S905, “the state management unit 306 determines whether or not the port operates in the RR mode 702. If the port operates in the RR mode 702, the step is performed. The process proceeds to S906, and if the port is not operating in the RR mode 702, the process proceeds to Step 905 ”and step S905 are allowed to coexist.

  According to the third embodiment, a device or software (hereinafter referred to as a simultaneous execution device) capable of realizing the function of Edge Relay 128 and the function of the bridge device 101 can be connected in multiple stages. Also, one of the simultaneous execution devices is connected to the bridge device 101 in the first embodiment or the second embodiment, and the other is connected to the Edge Relay 128, and the Edge Relay 128, the bridge device is changed according to the purpose of changing the switching processing position. 101, it is possible to freely select from the simultaneous execution apparatus.

The following are typical examples of aspects of the invention other than those described in the claims.
(1) A frame transfer method in a frame transfer apparatus that includes an arithmetic processing unit, a storage device connected to the arithmetic processing unit, and a network interface including one or more ports and is operable in a plurality of transfer modes. ,
The plurality of transfer modes include a first transfer mode, a second transfer mode, and a third transfer mode,
The frame transfer device includes:
A receiving unit for receiving the frame;
A transmitter for transmitting the frame;
A port determination unit for determining a port to transmit the frame;
A frame analysis unit for analyzing the received frame;
A learning unit that accumulates results analyzed by the frame analysis unit;
Holding a mode information indicating a transfer mode of the frame transfer device, switching the transfer mode based on the mode information, and controlling the frame transfer device;
With
The method
In the first transfer mode,
The frame transfer apparatus includes a step of executing transfer processing of the first frame based on a result of analysis of the first frame received from the port;
In the second transfer mode,
When the frame transfer device receives a second frame from a port to which another frame transfer device is connected, the second frame transfer processing is executed based on the analysis result of the second frame. And steps to
When the frame transfer device receives a third frame from a port to which a device other than the other frame transfer device is connected, the step of transferring the third frame to the other frame transfer device. ,
In the third transfer mode,
When the frame transfer apparatus receives a fourth frame from a port to which the other frame transfer apparatus is connected and the analysis result corresponding to the fourth frame is accumulated, Discarding 4 frames;
When the frame transfer device receives a fifth frame from a port to which a device other than the other frame transfer device is connected, or receives the fourth frame from a port to which the other frame transfer device is connected. And when the analysis result corresponding to the fourth frame is not accumulated, the first frame is analyzed based on the analysis result of the fourth frame or the analysis result of the fifth frame. And a step of executing transfer processing of the fourth frame or the fifth frame.
(2) The frame transfer device operates in either the first transfer mode or the second transfer mode before the transfer mode is switched,
The method further comprises:
The method includes a step of switching from the first transfer mode or the second transfer mode to the first transfer mode or the second transfer mode via the third transfer mode (1 ) Frame transfer method.
(3) The first frame transfer process includes:
Searching a transmission port for transmitting the first frame based on the result of the analysis of the first frame;
When one or more of the transmission ports are searched, transmitting the first frame from the searched one or more ports;
Discarding the first frame if the retrieved transmission ports are zero; and
The second frame transfer process includes:
Searching the transmission port for transmitting the second frame from the ports excluding the port to which the other frame transfer device is connected;
When one or more of the transmission ports are retrieved, transmitting the second frame from the retrieved one or more ports;
Discarding the second frame if the retrieved transmission ports are zero, and
The transfer process of the fourth frame is as follows:
Searching the transmission port for transmitting the fourth frame from among the ports excluding the port to which the other frame transfer device is connected;
When one or more of the transmission ports are searched, transmitting the fourth frame from the searched one or more ports;
Discarding the fourth frame if the retrieved transmission ports are zero, and
The transfer process of the fifth frame is as follows:
Accumulating the results of the analysis of the fifth frame;
Searching a transmission port for transmitting the fifth frame based on a result of the analysis of the fifth frame;
When one or more of the transmission ports are retrieved, transmitting the fifth frame from the retrieved one or more ports;
The frame transfer method according to (2), further comprising a step of discarding the fifth frame when the searched transmission ports are zero.
(4) The frame transfer device
Holds information about switching conditions,
The frame transfer method according to (3), wherein the transfer mode is switched when the switching condition is satisfied.
(5) The frame transfer method according to (3), wherein the frame transfer device switches the transfer mode when receiving an instruction to switch the transfer mode.
(6) The transfer mode switching instruction is defined by IEEE 802.1Qbg and is transmitted by a frame including information indicating a state of the frame transfer device and the other frame transfer device. The frame transfer method described in 1.
(7) The method further includes a step of stopping transfer of a frame received from a port connected to a device other than the other frame transfer device for a predetermined time when the transfer mode is switched. The frame transfer method according to (3).
(8) The method further includes a step of storing the received frame when a frame is received from a port to which a device other than the other frame transfer device is connected while the transfer of the frame is stopped.
The frame transfer method according to (7), further comprising a step of transferring the accumulated frame after the frame transfer stop state is cancelled.

101 bridge device 102 server device 104 node device 105 cable 108 arithmetic processing device 109 storage device 110 input / output device 111 network interface 114 shared bus 115 arithmetic processing device 116 storage device 117 input / output device 118 network interface 119 shared bus 120 overall control unit 121 Port control unit 124 Transfer port management table 125 I / O port 128 Edge Relay
129 Virtualization software 130 Virtual machine 211 Virtual cable 306 Status management unit 307 Control frame processing unit 308 Control frame generation unit 309 Delivery port determination unit 310 Port learning unit 311 Frame classification / information extraction unit 312 Frame storage unit 313 Transmission control unit 314 Frame Reception unit 315 Frame transmission unit 401 MAC address 402 VLAN_ID
403 Port ID
501 EVB_Bridge_status
502 EVB_station_status
503 EVB_Mode
504 RRCAP
505 RRCTR
506 RRREQ
507 RRSTAT
601 VEB mode 602 VEPA mode 603 TRANS mode 604 S0 state 605 S1 state 606 S2 state 607 S3 state 608 S4 state 609 S5 state 701 SW mode 702 RR mode 703 B0 state 704 B1 state 705 B2 state 706 B3 state 1301 d bridge 1301
1303 Server device 1306 Node device 1307 Cable 1308 Cable 1311 Cable

Claims (14)

A frame transfer device comprising an arithmetic processing device, a storage device connected to the arithmetic processing device, and a network interface having one or more ports, and operable in a plurality of transfer modes,
The plurality of transfer modes include a first transfer mode, a second transfer mode, and a third transfer mode,
The frame transfer device includes:
A receiving unit for receiving the frame;
A transmitter for transmitting the frame;
A port determination unit for determining a port to transmit the frame;
A frame analysis unit for analyzing the received frame;
A learning unit that accumulates results analyzed by the frame analysis unit;
Holding a mode information indicating a transfer mode of the frame transfer device, switching the transfer mode based on the mode information, and controlling the frame transfer device;
With
In the first transfer mode,
Based on the analysis result of the first frame received from the port, the transfer process of the first frame is executed,
In the second transfer mode,
When the second frame is received from the port to which the other frame transfer device is connected, based on the result of the analysis of the second frame, the second frame is transferred.
When a third frame is received from a port to which a device other than the other frame transfer device is connected, the third frame is transferred to the other frame transfer device,
In the third transfer mode,
When the fourth frame is received from the port to which the other frame transfer device is connected and the analysis result corresponding to the fourth frame is accumulated, the fourth frame is discarded. ,
When the fourth frame is received from the port to which the other frame transfer apparatus is connected and the analysis result corresponding to the fourth frame is not accumulated, the analysis of the fourth frame is performed. On the basis of the result of the fourth frame transfer processing,
When receiving the fifth frame from the port in which the other frame transfer apparatus other than the apparatus is connected, based on the results of the analysis of the fifth frame, executes the transfer processing of the fifth frame A frame transfer apparatus. The frame transfer device includes:
Before being switched the transfer mode is to operate in either the first transfer mode and the second transfer mode, the
When switching the transfer mode, switching from the first transfer mode or the second transfer mode to the first transfer mode or the second transfer mode via the third transfer mode. The frame transfer apparatus according to claim 1, wherein: In the transfer process of the first frame,
Based on the analysis result of the first frame, search for a transmission port for transmitting the first frame;
When one or more of the transmission ports are searched, the first frame is transmitted from the searched one or more ports.
If the retrieved transmission port is 0, the first frame is discarded,
In the transfer process of the second frame,
Searching for the transmission port for transmitting the second frame from the ports excluding the port to which the other frame transfer device is connected,
When one or more transmission ports are searched, the second frame is transmitted from the one or more searched ports.
If the retrieved transmission port is 0, the second frame is discarded,
In the transfer process of the fourth frame,
Searching for the transmission port for transmitting the fourth frame from the ports excluding the port to which the other frame transfer device is connected,
When one or more transmission ports are searched, the fourth frame is transmitted from the one or more searched ports.
If the retrieved transmission port is 0, the fourth frame is discarded,
In the transfer process of the fifth frame,
Based on the analysis result of the fifth frame, search for a transmission port for transmitting the fifth frame;
When one or more of the transmission ports are searched, the fifth frame is transmitted from the searched one or more ports.
3. The frame transfer apparatus according to claim 2, wherein when the searched transmission port is 0, the fifth frame is discarded. The frame transfer device includes:
Holds information about switching conditions,
The frame transfer device according to claim 3, wherein the transfer mode is switched when the switching condition is satisfied.   The frame transfer apparatus according to claim 3, wherein the frame transfer apparatus switches the transfer mode when receiving an instruction to switch the transfer mode.   6. The transfer mode switching instruction is defined by IEEE 802.1Qbg, and is transmitted by a frame including information indicating a state of the frame transfer device and the other frame transfer device. Frame transfer device.   4. The frame transfer apparatus according to claim 3, wherein when the transfer mode is switched, transfer of a frame received from a port connected to an apparatus other than the other frame transfer apparatus is stopped for a predetermined time. When a frame is received from a port to which a device other than the other frame transfer device is connected while the transfer of the frame is stopped, the received frame is accumulated,
8. The frame transfer apparatus according to claim 7, wherein the stored frame is transferred after the frame transfer stop state is released. A frame transfer device comprising: an arithmetic processing device; a storage device connected to the arithmetic processing device; and a network interface including one or more ports, each of the ports being operable in a plurality of transfer modes,
The frame transfer device is connected to another frame transfer device via a network,
The frame transfer device includes:
A receiving unit for receiving the frame;
A transmitter for transmitting the frame;
A port determination unit for determining a port to transmit the frame;
A frame analysis unit for analyzing the received frame;
A learning unit that accumulates results analyzed by the frame analysis unit;
A frame generation unit for generating a control frame for instructing control of the other frame transfer device;
A state management unit that holds mode information indicating a transfer mode of the frame transfer device, switches the transfer mode based on the mode information, and controls the frame transfer device;
With
The plurality of transfer modes are:
When a frame is received from the port, a transmission port for transmitting the frame is searched from the ports other than the port that has received the frame based on the analysis result of the received frame. A first transfer mode for transmitting the frame from the one or more searched ports when one or more are searched, and discarding the frame when the searched transmission ports are zero;
When a frame is received from the port, the transmission port for transmitting the frame is searched based on the analysis result of the received frame, and when one or more transmission ports are searched, the search is performed. A second transfer mode for transmitting the frame from one or more ports, and discarding the frame when the searched transmission ports are 0;
Including
The frame transfer device includes:
Transmitting a first control frame requesting switching of the transfer mode of the other frame transfer device from a first port to which the other frame transfer device is connected;
Receiving a second control frame requesting the switching process between the first transfer mode in the first port and the second transfer mode from said first port,
Executing the switching process based on the second control frame;
Generating a third control frame notifying the result of the switching process;
The frame transfer apparatus, wherein the generated third control frame is transmitted from the first port.   The first control frame, the second control frame, and the third control frame are frames defined in IEEE 802.1Qbg and including information indicating the states of the frame transfer device and the other frame transfer device. The frame transfer apparatus according to claim 9, wherein the frame transfer apparatus is provided. A first arithmetic processing unit, a first storage device connected to the first arithmetic processing unit, and a first network interface having one or more ports, each port being operable in a plurality of transfer modes A first frame transfer device, a second arithmetic processing device, a second storage device connected to the second arithmetic processing device, and a second network interface having one or more ports, A second frame transfer apparatus operable in a transfer mode, and a network system comprising:
The first frame transfer device and the second frame transfer device are connected via a network,
The plurality of transfer modes in the first frame transfer device include a first transfer mode or a second transfer mode,
The plurality of operation modes in the second frame transfer device include a third transfer mode, a fourth transfer mode, or a fifth transfer mode,
The first frame transfer device includes:
A first receiving unit for receiving the frame;
A first transmitter for transmitting the frame;
A first port determining unit for determining a port for transmitting the frame;
A first frame analysis unit for analyzing the received frame;
A first learning unit for accumulating results analyzed by the first frame analysis unit;
A first frame generation unit for generating a control frame for instructing control of the second frame transfer device;
A first state management unit that holds mode information indicating a transfer mode of the frame transfer device, switches the transfer mode based on the mode information, and controls the frame transfer device;
The second frame transfer device includes:
A second receiving unit for receiving the frame;
A second transmitter for transmitting the frame;
A second port determining unit for determining a port to transmit the frame;
A second frame analysis unit for analyzing the received frame;
A second learning unit for accumulating results analyzed by the second frame analysis unit;
A second frame generation unit for generating a control frame for instructing control of the first frame transfer device;
A second state management unit that holds mode information indicating a transfer mode of the frame transfer device, switches the transfer mode based on the mode information, and controls the frame transfer device;
In the first transfer mode,
When the first frame transfer apparatus receives the first frame from the port, the first frame transfer apparatus is configured to determine whether the first frame transfer device excludes the port that has received the first frame based on the analysis result of the first frame. The transmission port for transmitting the first frame is searched, and when one or more transmission ports are searched, the first frame is transmitted from the searched one or more ports, and the search is performed. The first frame is discarded when the number of transmitted ports is zero,
In the second transfer mode,
When the first frame transfer device receives a second frame from the port, the first frame transfer device searches for a transmission port for transmitting the second frame based on the analysis result of the second frame, and When one or more transmission ports are searched, the second frame is transmitted from the searched one or more ports. When the number of searched transmission ports is zero, the second frame is transmitted. Discard,
In the third transfer mode,
The second frame transfer device executes the transfer process of the third frame based on the analysis result of the third frame received from the port;
In the fourth transfer mode,
When the second frame transfer apparatus receives a fourth frame from the second port to which the first frame transfer apparatus is connected, the second frame transfer apparatus is configured to perform the first frame analysis based on the analysis result of the fourth frame. 4, when the fifth frame is received from the port to which a device other than the first frame transfer device is connected, the fifth frame is transferred to the second frame transfer device. Forward to
In the fifth transfer mode,
The second frame transfer apparatus receives a sixth frame from the second port to which the first frame transfer apparatus is connected, and an analysis result corresponding to the sixth frame is accumulated. If the seventh frame is discarded and the seventh frame is received from a port to which a device other than the first frame transfer device is connected, or the first frame transfer device is connected When the sixth frame is received from the second port and the analysis result corresponding to the sixth frame is not accumulated, the sixth frame or the seventh frame Based on the result of the analysis, the transfer process of the sixth frame or the seventh frame is executed,
The network system includes:
The second frame transfer device comprises:
A second control frame requesting the first frame transfer apparatus to switch the transfer mode based on the first control frame when a first control frame requesting the transfer mode switching is received Produces
Transmitting the generated second control frame to the first frame transfer device;
The first frame transfer device comprises:
Based on the second control frame, switching the transfer mode of the port to which the second frame transfer device is connected,
Generating a third control frame notifying that the transfer mode has been switched;
Transmitting the third control frame to the second frame transfer device;
The network system, wherein the second frame transfer apparatus switches the transfer mode after receiving the third control frame. The second frame transfer device includes:
Before receiving the first control frame, operate in either the third transfer mode or the fourth transfer mode,
After receiving the first control frame, switching from the third transfer mode or the fourth transfer mode to the fifth transfer mode,
The network system according to claim 11, wherein the network system is switched to the fourth transfer mode or the third transfer mode after receiving the fourth control frame.   The first control frame, the second control frame, and the third control frame are defined in IEEE 802.1Qbg, and indicate information about the states of the first frame transfer device and the second frame transfer device. The network system according to claim 12, wherein the network system includes a frame including The second frame transfer device includes:
When switching from the third transfer mode to the fourth transfer mode, or when switching from the fourth transfer mode to the third transfer mode, a device other than the first frame transfer device is connected. Stop forwarding frames received from the port for a specified time,
When a frame is received from a port connected to a device other than the first frame transfer device when transfer of the frame is stopped, the received frame is accumulated,
13. The network system according to claim 12, wherein the accumulated frame is transferred after the frame transfer stop state is released.

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