JP6062394B2 - Relay device and relay method - Google Patents

Description

  The present invention relates to a relay device and a relay method.

  In a communication system, there is a technique for preventing communication from being disabled even when a failure occurs by making a communication path redundant.

  An example of such a technique is Patent Document 1. In the technique disclosed in Patent Document 1, when the IPsec monitoring unit 112 detects an abnormality in IPsec communication on the working path, the MAC address associated with the Ethernet (registered trademark) interface of its own device is extracted from the bridge table 113 and this MAC is extracted. The communication path can be switched to the backup path by including the bridge control unit 111 that transmits the address to the opposite base via the backup path.

JP 2012-231368 A

  By the way, in the technique disclosed in Patent Document 1, since a packet for switching a route is transmitted via the Internet 701, the bandwidth of the Internet 701 is narrowed, and charging may occur depending on the communication system. There is a problem.

  An object of the present invention is to provide a relay device and a relay method capable of switching a communication path without narrowing a band or generating a charge.

In order to solve the above-described problems, the present invention provides a relay device that is disposed at a base connected to another base via a redundant communication path, and is provided for each of the redundant communication paths. In an L2-transparent relay device connected via a route selection device that selects a route with reference to the data link layer with respect to a communication device arranged in the base, the communication route is switched. When it is notified that the network is to be newly used, the relay device generates a packet having the MAC address of the communication device of the other base as a transmission source, and the base via the route selection device The route selected by the route selection device is changed by transmitting to the other device.
According to such a configuration, it is possible to switch communication paths without narrowing the bandwidth or incurring charges.

In addition, in the present invention, when a relay device other than that notified to become a new active system receives a packet whose source is the MAC address of the communication device of the other base, the other device The packet is not transferred to the base.
According to such a configuration, it is possible to reliably prevent a packet from being transferred to another base.
In addition, the present invention is characterized in that a notification that becomes a new active system is transmitted from the other base by switching the communication path.

Further, the present invention is a relay method of a relay device that is disposed at a base connected to another base via a redundant communication path and provided for each of the redundant communication paths. In the relay method of the L2 transmission type relay device connected via a route selection device that selects a route with reference to the data link layer with respect to the communication device arranged in the base, by switching the communication route When it is notified that the network is to be newly used, the relay device generates a packet having the MAC address of the communication device of the other base as a transmission source, and the base via the route selection device The route selected by the route selection device is changed by transmitting to the other device.
According to such a method, it is possible to switch the communication path without narrowing the bandwidth or charging.

  According to the present invention, it is possible to provide a relay device and a relay method capable of switching a communication path without narrowing a bandwidth or charging.

It is a figure which shows the structural example of the communication system which concerns on embodiment of this invention. It is a signal flow figure for demonstrating operation | movement of the communication system shown in FIG. It is an example of the learning table for relay stored in each communication apparatus of the communication system shown in FIG. It is a figure which shows the state from which a packet is transmitted from a client. It is a figure which shows the state of each learning table for relay after FIG. It is a figure which shows the state in which switching notification is made from CPE. It is a figure which shows an example of the information for performing switching notification. It is a figure which shows the state which the gateway X transmits a broadcast packet after receiving the notification of switching. It is a figure which shows the state of each learning table for relay after FIG. It is a figure which shows the state which receives the packet from a client. It is a figure which shows the state of each learning table for relay after FIG. It is a figure which shows the flow of the packet from a server to a client. It is a figure which shows the other structural example of the communication system which concerns on embodiment of this invention.

  Next, an embodiment of the present invention will be described.

(A) Description of Configuration of Embodiment FIG. 1 is a diagram illustrating a configuration example of a communication system according to an embodiment of the present invention. In the example shown in FIG. 1, the communication system has bases 10 and 20, and these bases 10 and 20 are connected by redundant communication paths 31 and 32.

  The base 10 includes a gateway X11 (hereinafter simply referred to as “gateway X”), a gateway Y12 (hereinafter simply referred to as “gateway Y”), an L2 (Layer 2) switch 13, and a server 14. Here, the gateway X has interfaces IF11 and IF12, and connects the communication path 31 and the L2 switch 13. Further, the gateway X is configured to transmit L2. The interface IF 12 is assigned “X” as a MAC (Media Access Control) address. The gateway Y has interfaces IF21 and IF22, and connects the communication path 32 and the L2 switch 13. Further, the gateway Y is configured to transmit L2. The interface IF 22 is assigned “Y” as the MAC address. The L2 switch 13 has interfaces IF31, IF32, and IF33, and selects the transmission destination of the received packet based on the MAC address handled in the second layer (data link layer) of the OSI (Open Systems Interconnection) reference model. Output. The server 14 corresponds to a server of the server client model, acquires predetermined information or executes predetermined processing based on a request from the client 23, and transmits data obtained as a result. The server 14 is assigned “B” as the MAC address.

  The base 20 has a CPE (Customer Premises Equipment) 21, a LAN (Local Area Network) 22, and a client 23. The CPE 21 is a communication device that is configured by a router, a switch, and the like and is arranged in the base 20. The LAN 22 is a local network arranged in the base 20. The client 23 corresponds to a client of the server client model, requests the server 14 to transmit predetermined information or execute processing, and receives information transmitted as a result. The client 23 is assigned “A” as the MAC address.

  The communication path 31 connects the CPE 21 and the gateway X so that data can be exchanged between them. The communication path 32 connects the CPE 21 and the gateway Y, and enables data exchange between them. Note that the communication paths 31 and 32 may be configured as physical lines, or may be configured as logical lines (for example, tunnel paths).

(B) Description of Operation of Embodiment Next, the operation of the embodiment shown in FIG. 1 will be described. FIG. 2 is a signal flow diagram for explaining the operation of the embodiment shown in FIG. For example, assume that the system is started after gateways X and Y are connected to the communication system shown in FIG. At this time, an example of the state of the relay learning table stored in the gateway X, the gateway Y, and the L2 switch 13 is shown in FIG. FIG. 3A shows a relay learning table stored in the gateway X. The relay learning table is a table that stores a MAC address of a communication device in association with an interface to which the communication device is connected. In the example of FIG. 3A, since the gateway X is in a state immediately after being connected, the relay learning table is in an empty “-” state. FIG. 3B shows the relay learning table stored in the gateway Y, which is in a state immediately after the gateway Y is connected, so that the relay learning table is in an empty “-” state. Yes. FIG. 3C shows the learning table for relay stored in the L2 switch 13. In this example, “B” which is the MAC address of the server 14 and the interface to which the server 14 is connected. “IF33” is stored in association with each other.

  In such a state, it is assumed that the communication path 31 is set to the active system (main system) and the communication path 32 is set to the backup system (backup system). Then, at the timing T1 shown in FIG. 2, when the client 23 transmits a packet to the server 14 as shown in FIG. 4, the CPE 21 transmits this packet via the communication path 31 as shown in FIG. To do. As a result, the gateway (GW) X receives this packet. The source MAC address of this packet is “A”, and the destination MAC address is “B”. Incidentally, the gateway X (same as the gateway Y) is the L2 transmission type as described above. Therefore, when the gateway X receives such a packet, the transmission source MAC address remains “A”, the packet is transferred to the L2 switch 13 at the timing T2, and the table update process P1 is executed. When the table update process P1 is executed, “A” (the MAC address of the client 23) is stored as the MAC address in the relay learning table of the gateway X as shown in FIG. "IF11" (the interface that received the packet from the client 23) is stored.

  The packet output from the IF 12 of the gateway X is input from the IF 31 of the L2 switch 13. When receiving the packet, the L2 switch 13 executes a table update process P2 shown in FIG. As described above, since the gateway X (as well as the gateway Y) is an L2 transmission type gateway, the source address remains “A”. When the table update process P2 is executed, as shown in FIG. 5C, the relay learning table of the L2 switch 13 stores “A” (the MAC address of the client 23) as the MAC address. As an interface, “IF31” (the interface that received the packet from the client 23) is associated and stored.

  When a packet is transmitted from the server 14 to the client 23 after the above processing is completed, the packet is received by the L2 switch 13. The L2 switch 13 acquires “A” that is the transmission destination MAC address of the packet, acquires “IF31” that is the interface from the learning table for relay shown in FIG. 5C, and receives the received packet from the interface IF31 Output. The gateway X acquires “A” that is the transmission destination MAC address from the packet input via the IF 12, acquires “IF11” of the interface from the relay learning table shown in FIG. 5A, and receives the input packet. Are output from the interface IF11. As a result, the packet transmitted from the server 14 is transmitted to the client 23 via the L2 switch 13, gateway X, and CPE 21. Thereby, communication between the server 14 and the client 23 becomes possible.

  Next, it is assumed that a failure has occurred in the communication path 31 in the above state. In such a case, for example, the CPE 21 detects a failure and executes a process of switching the active system from the communication path 31 to the communication path 32. More specifically, as shown in FIG. 6, the CPE 21 notifies the gateway Y of switching (notification of switching from the standby system to the active system). In FIG. 2, the switching notification is executed at timing T3. As a specific method for performing the switching notification, for example, Circuit Status AVP (Attribute Value Pair) (specified in RFC 3931) as shown in FIG. 7 can be used. FIG. 7 shows a 16-bit signal, and “A” of the F-th bit can be used as information for switching notification. When this bit is “1”, it indicates Active, and when this bit is “0”, it indicates Inactive. In the case of Active, it is indicated that the active system is changed from the standby system. In the case of Inactive, it is indicated that the active system becomes the standby system. When the communication path 31 is communicable, the gateway X is notified of switching from the active system to the standby system by sending a signal in which the F-th bit shown in FIG. 7 is set to “0”. You may make it do.

  The gateway Y that receives the switching notification from the CPE 21 executes the switching process P3 shown in FIG. More specifically, as shown in FIG. 8, the gateway Y sets the source (SRC: Source) MAC address to “A” (the MAC address of the communication device existing at the end of the communication path to be newly used). , A packet (broadcast packet in FIG. 8) is generated with the transmission destination (DST: Destination) as another device in the base 10 (“ALL” indicating all other devices in the example of FIG. 8). At timing T4 shown, the data is output from the interface IF 22 to which the L2 switch 13 is connected. Here, if it is normal, the source MAC address of the packet transmitted by the gateway Y should be “Y”, but in this embodiment, a new active system is newly added to the packet transmitted at this time. The MAC address of the communication device (client 23) existing ahead of the communication path 32 is added. Note that the transmission source MAC address to be added when the switching notification is made can be stored in advance in the gateway Y (and gateway X) as Config information, for example.

  When a broadcast packet as shown in FIG. 8 is transmitted from the gateway Y, the L2 switch 13 receives it via the interface IF 32. Since the received packet is a broadcast packet (the transmission destination is “ALL”), the L2 switch 13 transfers this packet to the gateway X at timing T5 as shown in FIG. Further, the L2 switch 13 executes a table update process P4 as shown in FIG. More specifically, since the source MAC address of the received packet is “A”, the L2 switch 13 determines that the communication device with the MAC address “A” is connected to the interface IF 32, and FIG. The interface “IF31” associated with the MAC address “A” shown in (C) is changed to the interface “IF32” as shown in FIG. 9C. As a result, thereafter, the packet received by the L2 switch 13 and having the transmission destination MAC address “A” is output from the interface IF 32.

  The gateway X that has received the broadcast packet from the L2 switch 13 executes the table update process P5 as shown in FIG. More specifically, in the gateway X, the transmission source MAC address of the received packet is “A” and the interface is “IF12”. The relay learning table at that time is shown in FIG. As shown, since the MAC address “A” is associated with the interface “IF11”, these do not match, so it is determined that the configuration of the system has changed, and the relay learning table is displayed as shown in FIG. As shown, the interface associated with the MAC address “A” is updated from “IF11” to “IF12”. As a result, thereafter, the gateway X outputs from the interface IF 12 a packet in which “A” is stored as the destination MAC address. Since a failure has occurred in the communication path 31, the broadcast packet received by the gateway X is not sent to the communication path 31. Note that, as described above, the gateway X may not transfer the packet received after receiving the notification from the CPE 21 that it becomes a standby system to the base 20. According to such a configuration, it is possible to reliably prevent a packet from being transmitted from the gateway X to the communication path 31 to limit the bandwidth or charge.

  As a result of the above processing, after the relay learning table of the gateway X and the L2 switch 13 is updated, a packet is transmitted from the client 23 to the server 14 as shown in FIG. 10 (the source MAC address is “ A "packet is transmitted). In FIG. 2, the packet is transmitted via the CPE 21 at the timing T6. When the gateway Y receives such a packet, the table update process P6 is executed. More specifically, the gateway Y determines that the communication device with the MAC address “A” is connected to the interface IF 21, and, as shown in FIG. A ”is stored, and“ IF21 ”is stored in association with the interface.

  After the above processing is executed and the relay learning table is updated to the state of FIG. 11, as shown in FIG. 12, the packet (source MAC address is “B”) from the server 14 to the client 23, Assume that a packet whose destination MAC address is “A” is transmitted. The L2 switch 13 refers to the relay learning table shown in FIG. 11C, outputs this packet from the interface IF 32, and supplies it to the gateway Y. The gateway Y refers to the relay learning table shown in FIG. 11B, outputs a packet from the interface IF 21, and supplies the packet to the client 23 via the communication path 32 and the CPE 21. Thereby, the switching from the communication path 31 to the communication path 32 is completed.

  As described above, in the embodiment of the present invention, when the communication path is switched, as shown in FIG. 8, the gateway Y newly used as the active system is connected to the communication path 32. A packet whose source is the MAC address (“A”) of the device (client 23) is transmitted. Thereby, the relay learning table of the apparatus in the base 10 can be rewritten reliably. In the present embodiment, since the gateway Y transmits such a packet, the packet is not transmitted from the base 20 to the base 10 as compared with the case where the base 20 transmits such a packet. It is possible to prevent the bandwidth from being limited or charged.

  In the present embodiment, since broadcast packets are used as the packets shown in FIG. 8, information can be reliably transmitted to all communication devices in the base 10.

  In the present embodiment, for the gateway X that newly becomes the standby system, a failure has occurred in the communication path 31, so that the broadcast packet received by the gateway X is not sent out to the communication path 31. Further, as described above, the CPE 21 notifies the standby gateway X, and the gateway X that has received the notification prevents the packet from being forwarded to the base 20 thereafter. It is transmitted to the communication path 31 and it is possible to reliably prevent the bandwidth from being limited or charged.

(C) Description of Modified Embodiment It goes without saying that the above embodiment is merely an example, and the present invention is not limited to the case described above. For example, in each of the above embodiments, as a method of acquiring the transmission source MAC address of the broadcast packet shown in FIG. 8, a method of storing in advance as Config information is adopted, but other methods may be adopted. Good. Specifically, notification from the CPE 21 may be performed, or the administrator may notify by manual operation. In the above embodiment, a broadcast packet is used. However, a multicast packet transmitted to a specific partner may be used.

  In the above embodiment, the case where there is one active system and one standby system has been described as an example, but two or more standby systems may exist. FIG. 13 shows a configuration example in the case where two standby systems exist. In the example of FIG. 13, a communication path 33 and a gateway Z are newly added. In such a configuration, when the working system is switched from the gateway X to the gateway Z, the gateway Z may be made to perform the same operation as that when the gateway Y is switched to the working system. In addition, when switching the working system from the gateway X to the gateway Y, the gateway X and the gateway Y need not execute the same operation as described above, but for the gateway Z, the broadcast packet received from the gateway Y Based on the above, “A” is stored as the MAC address in the relay learning table, and “IF42” is stored in association with the interface. In addition, when a gateway other than that which has been notified of becoming a new active system receives a packet whose source is the MAC address of the client 23 which is a communication device of another base 20, the gateway 20 Therefore, by not transferring the packet, it is possible to prevent the packet from being sent to the communication path.

  In the above embodiment, the base 20 has only one client, but a plurality of clients may be arranged. In that case, the broadcast packet shown in FIG. 8 may be repeatedly transmitted by the number of clients. For example, when the clients A, C, and D exist in the base 20, the gateway that newly becomes the active system transmits three packets with source MAC addresses “A”, “C”, and “D”. You just have to do it.

  In the above embodiment, the base 10 has only one server, but a plurality of servers may be arranged. In that case, the number of ports of the L2 switch 13 may be increased according to the number of servers, and information corresponding to each server may be stored in the relay learning table.

  In the above embodiment, the information shown in FIG. 7 is used when switching between the active system and the standby system, but the information may be executed using other information.

  In the above embodiment, the server is arranged at the base 10 and the client is arranged at the base 20. However, the client is arranged at the base 10 and the server is arranged at the base 20, or Other communication devices may be arranged. That is, the “communication device” described in the claims may be either a server or a client.

10 locations 11, 12 Gateway (relay equipment)
13 L2 switch (route selection device)
14 Server (communication device)
20 locations (other locations)
21 CPE
22 LAN
23 Client (communication device)

Claims (4)

A relay device that is disposed at a base connected to another base via a redundant communication path, and is provided for each of the redundant communication paths, the communication being disposed within the base. In an L2 transmission type relay device connected to a device via a route selection device that selects a route with reference to the data link layer,
When it is notified by switching the communication path that the network is newly used, the relay apparatus generates a packet whose source is the MAC address of the communication apparatus of the other base, and the path selection A relay device, wherein a route selected by the route selection device is changed by transmitting to another device in the base via the device.   When a relay device other than that which has been newly notified of becoming the active system receives a packet whose source is the MAC address of the communication device of the other base, the relay base The relay apparatus according to claim 1, wherein no packet is transferred. The relay apparatus according to claim 1 or 2, wherein a notification that becomes a new active system is transmitted from the other base by switching the communication path. A relay device relay method provided at each base connected to another base via a redundant communication path and provided for each of the redundant communication paths, wherein the relay apparatus is provided in the base. In a relay method of an L2 transmission type relay device connected via a route selection device that selects a route with reference to the data link layer for a communication device to be
When it is notified by switching the communication path that the network is newly used, the relay apparatus generates a packet whose source is the MAC address of the communication apparatus of the other base, and the path selection A relay method of a relay device, wherein the route selected by the route selection device is changed by transmitting to another device in the base via the device.

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