JP6214378B2 - Switch device and network system - Google Patents

Description

  The present disclosure relates to a switch device and a network system having a loop detection function.

  In a computer network having a star-type or tree-type connection configuration, if there is a switch device connected in a ring due to an incorrect line connection or network configuration, broadcast data is repeatedly transmitted to multiple ports by that switch device. As a result, a so-called broadcast storm occurs, causing a failure in the communication state of the entire network.

  As a switch device for preventing the occurrence of this broadcast storm, a switch device having a loop detection function for detecting the occurrence of a loop in which the same data transfer is repeated is known (for example, Patent Document 1). And 2). In this switch device, when a loop detection frame for detecting a loop on the network is transmitted from each port of the own device and the frame is received by the own device, the received port is blocked and an LED (Light Emitting Diode) A loop is displayed on the lamp to inform the network administrator and user.

JP 2006-217696 A JP 2009-207028 A

  However, the above-described loop detection function of the switch device only displays that the occurrence of the loop has been detected on the LED lamp of its own device, and does not display anything on the wrongly connected switch device. Absent. In a network configured using such a switch device, if the switch device that previously detected the loop among the two misconnected switch devices is installed in an invisible place, the network administrator Although the user cannot recognize and broadcast storms are prevented by blocking the port, they can be left in an erroneous connection state.

  The present invention has been made in view of such a point, and the object of the present invention is that even if the switch device that detects a loop generated in the network is in an invisible place, a network administrator or a user can The purpose is to recognize the occurrence of the loop.

  In order to achieve the above object, according to the present invention, in addition to displaying that the occurrence of the loop is detected on the switch device that has detected the loop based on the loop detection frame, the other party erroneously connected to this switch device is displayed. The switch device also displays that the occurrence of a loop has been detected.

  Specifically, the present invention has a plurality of ports connected to a computer network, and includes a switch device that relays communication between devices connected to different ports, and a plurality of the switch devices. The following solution is taken for the network system.

  That is, the first aspect of the present invention is a switch device, which generates a loop detection frame including identification information of its own device, and periodically transmits the loop detection frame from an arbitrary port; A loop detection processing unit that detects occurrence of a loop when one of a plurality of ports receives a loop detection frame transmitted from the own device and blocks the port that transmitted the loop detection frame; and Display means for displaying that the occurrence of the loop is detected by the loop detection processing section. Then, according to the first aspect of the present invention, the loop detection processing unit transmits a block notification frame from the port before blocking the port that received the loop detection frame. When the blocking notification frame transmitted from the apparatus is received, the display means displays that the occurrence of a loop is detected in the other apparatus.

  In this first aspect, when the loop detection processing unit detects the occurrence of a loop, the block notification frame is transmitted before the port of the own device is blocked to the erroneously connected partner switch device. When the blocking notification frame is received from the connected other device, the display means displays that the occurrence of the loop is detected in the other device. Therefore, the switch devices according to the first aspect of the present invention When a connection is mistaken and a loop occurs in the network due to this, it can be displayed that the occurrence of the loop is detected in both switch devices. As a result, even if one of the switch devices that detected a loop in the network based on the loop detection frame is in an invisible place, the network administrator or the user can indicate that the loop has been detected by the other switch device. The occurrence of the loop can be recognized.

  The loop detection processing unit may be configured to block a port that has received the block notification frame when a block notification frame transmitted from another device is received at any of the plurality of ports.

  The display means is preferably an LED lamp provided for each port.

  According to this configuration, it is possible to easily identify a port where a loop has occurred from a plurality of ports, and it is possible to quickly eliminate errors in line connection and network configuration.

  According to a second aspect of the present invention, there is provided a network system having a tree-type or star-type connection configuration, comprising a plurality of switch devices according to the first aspect of the present invention. .

  According to the second aspect, when the switch devices of the first aspect of the present invention are erroneously connected to each other and the occurrence of a loop due to this is detected by one switch device based on the loop detection frame, the loop device Even if the switch device that detected the signal is invisible to the public, the other switch device displays that the loop has been detected, so that the network administrator or the user can recognize the occurrence of the loop.

  According to the present invention, even when a switch device that detects a loop that has occurred in the network is in an invisible place, the occurrence of the loop is recognized by the display of the partner switch device erroneously connected to the switch device. Can do.

FIG. 1 is a configuration diagram of a network system according to an embodiment of the present invention. FIG. 2 is a block diagram showing the configuration of the switch device according to the embodiment of the present invention. FIG. 3 is a diagram illustrating a format of a loop guard control frame according to the embodiment of the present invention. FIG. 4 is a flowchart of the loop guard control of the switch device according to the embodiment of the present invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings. The following embodiments are essentially preferable examples, and are not intended to limit the scope of the present invention, its application, or its use.

  In this embodiment, a network system having a tree-type connection form will be described as an example of the network system according to the present invention. FIG. 1 is a configuration diagram of a network system 1 according to this embodiment. The network system 1 includes an upper layer group 3A and a lower layer group 3B each consisting of a partial tree. The upper layer group 3A is provided in the lower layer of the backbone network 2, and the lower layer group 3B is provided in the lower layer of the upper layer group 3A.

  Each of the upper layer group 3A and the lower layer group 3B includes a plurality of switch devices 5a to 5c and 5d to 5g, and is configured in a tree-type connection form. The switch devices 5a to 5c and 5d to 5g are devices that have a plurality of ports 11 connected to a computer network and relay communication between devices connected to different ports 11 as will be described in detail later. It is also called a switching hub or a network switch.

  One switch device 5c at the lowest level among the plurality of switch devices 5a to 5c in the upper layer group 3A is connected to the switch device 5d at the highest level of the lower layer group 3B. Although not shown, each of the switch devices 5e and 5g at the lowest level of the lower layer group 3B has a personal computer, a printer, etc. connected to other ports 11 other than the port 11 connected to the upper level switch devices 5d and 5f. Various terminal devices are connected.

  In the network system 1, each of the switch devices 5a to 5c in the upper layer group 3A is installed in a place that is easily noticeable, for example, a work place of a network administrator or a user, and is lower than the second level in the lower layer group 3B. The level switching devices 5d, 5e, and 5f include switching devices 5f that are installed in places that are difficult to see, for example, rooms that are not normally accessible by people or outdoor enclosures.

  Here, among the switch devices 5a, 5b, and 5c of the upper layer group 3A, the switch device 5c connected to the switch device 5d of the lower layer group 3B and the switch device 5f installed in a place that is not easily noticeable in the lower layer group 3B Is connected (indicated by a two-dot chain line in FIG. 1), when the switch device 5c of the upper layer group 3A is used as a frame transmission source, the lower layer group 3B is switched from the switch device 5c. Since the frame transmitted toward the switch device 5d is transmitted toward the own device 5c due to an erroneous connection with the switch device 5e of the lower layer group 3B, a loop (indicated by an arrow in FIG. 1) Occurs).

  The switch device 5 of the present embodiment has a loop detection function for detecting such a loop, and blocks the port 11 where the loop is generated, thereby preventing the effects of the loop from spreading to the entire network system 1. . In the network system 1, the switch devices 5 having the same configuration are used for the switch devices 5a to 5c of the upper layer group 3A and the switch devices 5d to 5g of the lower layer group 3B.

  FIG. 2 is a block diagram showing the configuration of the switch device 5. The switch device 5 has a plurality of physical ports 11, for example, 4 to 8 (four in the example shown in FIG. 2). In addition, the switch device 5 controls the LED lamp 13 provided for each port 11, the switching processing unit 15 that performs switching processing of the relay destination port 11 for the frame received from the port 11, and the open / closed state of the port 11. The port control part 17 and the LED control part 19 which controls the display state of each LED lamp 13 are provided.

  Furthermore, the switch device 5 generates a loop detection frame 100a (see FIG. 3) for detecting a loop in the network system 1 and periodically transmits the loop detection frame 100a from an arbitrary port 11, A control frame receiving unit 23 that receives a loop guard control frame 100 for preventing a loop in the network, such as the loop detection frame 100a, via the switching processing unit 15, and the control frame receiving unit 23 is notified of this. And a loop detection processing unit 25 that detects the occurrence of a loop based on the loop guard control frame 100 and copes with this.

  The LED lamp 13 is a display unit that displays the usage status of the corresponding port 11, for example, the link status, data communication (transmission / reception) status, and loop detection status between the port 11 and the connected device by lighting or blinking. The LED control unit 19 monitors the link state and communication state of each port 11 and switches the display state of the LED lamp 13 according to the use state of each port 11.

  When the switching processing unit 15 receives a frame via the port 11, the switching processing unit 15 analyzes the received frame and identifies information on a source MAC (Media Access Control) address and information on a destination MAC address included in the frame. . The switching processing unit 15 has an address table in which the transmission destination address and the corresponding port 11 are learned in advance, and based on the address table, the relay contents of the frame, that is, unicast, multicast, or flooding are determined. Then, the frame is transmitted to the port 11 corresponding to the relay content.

  In addition, when the switching processing unit 15 receives the loop guard control frame 100 at any one of the plurality of ports 11, the switching unit 15 determines that the frame 100 is looped based on a protocol identification field 104 described later included in the frame 100. The guard control frame 100 is identified and transferred to the control frame receiving unit 23. The control frame receiving unit 23 temporarily holds the loop guard control frame 100 and appropriately transfers the held frame 100 to the loop detection processing unit 25.

  The loop detection processing unit 25 includes a loop detection control unit 27 that executes loop guard control for preventing a loop in the network system 1 based on the loop guard control frame 100 delivered from the control frame receiving unit 23, and the loop detection. A loop detection port control unit 29 that controls the open / close state of a specific port 11 by a loop guard control operation by the control unit 27, and a loop detection LED that controls the display state of the LED lamp 13 of the port 11 blocked by the loop guard control operation. The control unit 31 includes a block notification frame transmission unit 33 that transmits a block notification frame 100b to the partner switch device 5 connected to the port 11 blocked by the loop guard control operation.

  The blocking notification frame 100b is a frame for notifying the other switch device 5 connected to the port 11 from the port 11 where the loop is generated that the port 11 of the own device is blocked, in other words, detecting the occurrence of the loop. This is a frame for notifying. The loop guard control frame 100 is one of the block notification frame 100b and the loop detection frame 100a, and is distinguished from other frames.

  Here, the contents of the loop guard control frame 100 will be described. FIG. 3 is a diagram illustrating a format of the loop guard control frame 100. The loop guard control frame 100 is a untagged frame having a size of 64 bytes. The fields 101 to 106 shown in FIG. 3 and an FCS (Frame Check Sequence) for detecting errors in these fields 101 to 106 are shown. Padding data is set in the other fields.

  The transmission destination field 101 is a field having a size of 6 bytes, and a MAC address that is identification information of a transmission destination device is set here. In the loop detection frame 100a, a multicast address is set in the transmission destination field 101. In the blockage notification frame 100b, the address of the switch device 5 connected to the port 11 where the loop occurs is set in the transmission destination field 101. The transmission source field 102 is a field having a size of 6 bytes, and a MAC address that is identification information of the transmission source switch device 5 (own device) is set here.

  The length field 103 is a field having a size of 2 bytes, and the effective data size of the loop guard control frame 100 is set here. The protocol identification field 104 is a field having a size of 6 bytes, and identification information indicating that it is the loop guard control frame 100 is set here. For example, “0x01” is set in the protocol identification field 104 of the loop guard control frame 100, and “0x00” is set in the protocol identification field 104 of other frames.

  The type field 105 is a field having a size of 1 byte, and type information indicating whether it is the loop detection frame 100a or the blockage notification frame 100b in the loop guard control frame 100 is set here. For example, “0x00” is set in the type field 105 of the loop detection frame 100a, and “0x11” is set in the type field 105 of the block notification frame 100b. The transmission port number field 106 is a field having a size of 2 bytes, and a port number for outputting a frame is set here.

  Upon receiving such a loop guard control frame 100, the loop detection control unit 27 determines whether the loop guard control frame 100 is the loop detection frame 100a based on the type field 105 included in the frame 100 or a blockage notification. Whether the frame is 100b is identified. When the loop guard control frame 100 is the loop detection frame 100a, the loop detection control unit 27 transmits the loop detection frame 100a from the own device from the transmission source field 102 included in the frame 100. It is determined whether or not.

  When the loop detection control unit 27 determines that the loop guard control frame 100 is the loop detection frame 100a and is transmitted from the own apparatus, the loop detection control unit 27 executes loop guard control. In this loop guard control, the port 11 that transmitted the loop detection frame 100a is regarded as the port where the loop occurs, and the information of the port 11 is used as the loop detection port control unit 29, the loop detection LED control unit 31, and the blocking notification frame transmission unit. 33 is notified. The loop detection port control unit 29 closes the notified port 11 in the port control unit 17. Further, the loop detection LED control unit 31 controls the LED control unit 19 to cause the LED lamp 13 corresponding to the notified port 11 to perform loop detection display for displaying that a loop has been detected. This loop detection display is a display by lighting or blinking in the same color or a different color as the display indicating the link state or the data communication state. Further, the block notification frame transmitting unit 33 transmits the block notification frame 100b from the port 11 to the partner switch device 5 connected to the port 11 via the switching processing unit 15 before the notified port 11 is blocked. Send.

  On the other hand, when the loop detection control unit 27 determines that the loop guard control frame 100 is the loop detection frame 100a but is transmitted from another device, the loop detection frame 100a is directly detected as a loop. The data is transferred to the frame transmission unit 21 and transmitted from the port 11 linked up via the switching processing unit 15.

  The loop detection control unit 27 also executes the loop guard control when it is determined that the loop guard control frame 100 is the blockage notification frame 100b from the other switch device 5. In this loop guard control, the port 11 that has received the block notification frame 100b is regarded as a port where a loop has occurred, and information on the port 11 is notified to the loop detection port control unit 29 and the loop detection LED control unit 31. The loop detection port control unit 29 closes the notified port 11 in the port control unit 17. Further, the loop detection LED control unit 31 controls the LED control unit 19 to cause the LED lamp 13 corresponding to the notified port 11 to perform loop detection display.

  When the communication cable is pulled out from the port 11 blocked by the loop guard control, the port control unit 17 releases the blocked state of the port 11. Similarly, when the communication cable is pulled out from the port 11 blocked by the loop guard control, the LED control unit 19 stops the loop detection display of the LED lamp 13 corresponding to the port 11.

  The flow of loop guard control by the switch device 5 is shown in FIG. When the power is turned on in the network system 1 and any port 11 is linked up, the switch device 5 performs loop guard control according to the flow shown in FIG.

  First, in step ST1, the loop detection frame 100a is transferred from the loop detection frame transmission unit 21 to the switching processing unit 15, and transmitted from the port 11 linked up via the switching processing unit 15. The transmission of the loop detection frame 100a in step ST1 is performed a plurality of times at predetermined intervals over a predetermined period. In the present embodiment, the loop detection frame 100a is transmitted three times at intervals of 2 seconds over, for example, 6 seconds. When the loop detection frame 100a is transmitted in step ST1, the process proceeds to step ST2.

  In step ST2, it is monitored whether or not the loop guard control frame 100 is received by the port 11 in the link-up state among the plurality of ports 11. In this step ST2, when the loop guard control frame 100 is not received within a predetermined time (for example, several seconds) from the transmission of the loop detection frame 100a in step ST1, the process returns to step ST1 and the loop detection frame 100a is set again. The transmission is performed from the port 11 in the link-up state, and the steps after step ST2 are executed. On the other hand, when the loop guard control frame 100 is received in step ST2, the process proceeds to step ST3.

  At this time, whether the frame received at any one of the ports 11 in the link-up state is the loop guard control frame 100 or another frame is indicated in the protocol identification field 104 included in the frame. Determine based on. Specifically, when the value set in the protocol identification field 104 of the received frame is “0x01”, it is determined that the frame is the loop guard control frame 100, and the protocol identification field of the received frame is determined. When the value set in 104 is “0x00”, it is determined that the frame is a frame other than the loop guard control frame 100.

  In step ST3, whether or not the loop guard control frame 100 is the loop detection frame 100a is determined based on the type field 105 included in the frame 100. Specifically, when the value set in the type field 105 of the received frame is “0x00”, it is determined that the frame is the loop detection frame 100a, and is set in the type field 105 of the received frame. If the obtained value is not “0x00”, it is determined that the frame is other than the loop detection frame 100a. At this time, if it is determined that the loop guard control frame 100 is the loop detection frame 100a, the process proceeds to step ST4. On the other hand, if it is determined that the loop guard control frame 100 is another frame that is not the loop detection frame 100a, the process proceeds to step ST8.

  In step ST4, it is determined based on the transmission source field 102 included in the frame whether or not the loop detection frame 100a is transmitted from the own apparatus. At this time, if it is determined that the loop detection frame 100a is transmitted from the own apparatus, the process proceeds to step ST5. On the other hand, if it is determined that the loop detection frame 100a is not transmitted from the own apparatus but transmitted from another apparatus, the process proceeds to step ST6.

  In step ST5, the blockage notification frame 100b is transmitted from the port 11 that transmitted the loop detection frame 100a to the counterpart switch device 5 that is erroneously connected to the port 11. When the transmission of the blockage notification frame 100b is completed in step ST5, the process proceeds to step ST7. In step ST7, the port 11 that transmitted the blocking notification frame 100b, that is, the port 11 that transmitted the loop detection frame 100a is blocked. If the port 11 is blocked in step ST7, the process proceeds to step ST11.

  In step ST6, the loop detection frame 100a is transferred to each port 11 via the switching processing unit 15, and transmitted from the linked port 11. When the transmission of the loop detection frame 100a is completed in step ST6, the process returns to step ST1 and the subsequent steps are executed again.

  In step ST8, it is determined based on the type field 105 included in the frame 100 whether or not the loop guard control frame 100 is the blockage notification frame 100b. Specifically, when the value set in the type field 105 of the received frame is “0x11”, it is determined that the frame is the blocking notification frame 100b, and is set in the type field 105 of the received frame. If the value is not “0x11”, it is determined that the frame is another frame that is not the blockage notification frame 100b. At this time, if the loop guard control frame 100 is the blockage notification frame 100b, the process proceeds to step ST9. On the other hand, when the loop guard control frame 100 is another frame other than the blockage notification frame 100b, the process proceeds to step ST10.

  In step ST9, the port 11 that has received the block notification frame 100b is blocked. When the port 11 is blocked in step ST9, the process proceeds to step ST11. In step ST10, it is determined that the received frame 100 is not the normal loop guard control frame 100 and is discarded. And it returns to step ST1 and performs the subsequent steps again.

  In step ST11, the LED lamp 13 corresponding to the port 11 closed in step ST7 or step ST9 is caused to perform loop detection display, and the loop guard control is terminated. This loop guard control is executed every time any one of the plurality of ports 11 is linked up.

  In the switch device 5 having the above configuration, when the occurrence of a loop is detected based on the loop detection frame 100a, before the port 11 at the loop occurrence location of the own device is blocked against the erroneously connected partner switch device 5 While the blockage notification frame 100b is transmitted to notify the occurrence of a loop, on the other hand, when the blockage notification frame 100b is received from the misconnected partner switch device 5, the other switch device 5 detects the occurrence of a loop. Is displayed on the LED lamp 13 corresponding to the port 11 that received the frame.

  Therefore, a loop is generated in the network system 1 due to the erroneous connection shown in FIG. 1 described above, and this loop is first detected by the switch device 5f of the lower layer group 3B installed in a place where it is difficult to see. In addition, since the loop detection is also displayed on the LED lamp 13 of the switch device 5c in the upper layer group 3A erroneously connected to the switch device 5f, the network administrator or the user can recognize the occurrence of the loop. . In addition, since the loop detection display is displayed on the LED lamp 13 provided for each port 11 of the switch device 5, it is possible to specify the port 11 that is erroneously connected to both the switch devices 5c and 5f.

  In the above embodiment, the LED lamps 13 provided for each port 11 of the switch device 5 are provided as display means, and each of these LED lamps 13 performs a loop detection display for displaying the loop detection. In addition to the LED lamp 13, the switch device 5 includes notifying means such as a buzzer as a display means, and when the loop detection control unit 27 detects the occurrence of a loop, the notifying means emits an alarm sound. May display that the occurrence of a loop has been detected. Further, an SNMP (Simple Network Management Protocol) trap may be notified together with or instead of the display by the LED lamp 13 and the notification means.

  In the above embodiment, all the switch devices 5a to 5g in the upper layer group 3A and the lower layer group 3B constituting the network system 1 are the switch devices 5 having the same configuration. However, the present invention is not limited to this. 1 may include a switch device having another configuration that does not perform the transmission of the blocking notification frame 100b when the occurrence of a loop is detected and the loop guard control by the reception of the frame 100b. It does not matter as long as at least two of the disclosed switch devices 5 are included.

  Even with such a configuration, when the switch devices 5 disclosed in the above embodiment are erroneously connected to each other and the occurrence of a loop due to this is detected by one switch device 5 based on the loop detection frame 100a, the loop device Even if the switch device 5 that detects this is invisible to the public, the other switch device 5 also displays the loop detection, so that the network administrator or user can recognize the occurrence of the loop.

  In the above embodiment, the network system 1 according to the present invention has been described by taking the network system 1 having a tree-type connection form as an example. However, the present invention is not limited to this, and the network having a star-type connection form. The present invention can also be applied to a system, and of course, the present invention can also be applied to a network system having a hybrid connection form in which these tree type or star type connection forms and other connection forms such as a ring type and a bus type are combined. it can.

  As described above, the present invention is useful for a switch device and a network system. In particular, even if a switch device that detects a loop that has occurred in the network is in an invisible place, a network administrator or a user can It is suitable for a switch device and a network system that are required to be able to recognize the occurrence of a loop.

DESCRIPTION OF SYMBOLS 1 Network system 5 Switch apparatus 5a-5g Switch apparatus 11 Port 13 LED lamp (display means)
21 Loop detection frame transmission unit 25 Loop detection processing unit 100a Loop detection frame 100b Blockage notification frame

Claims (4)

A switch device having a plurality of ports connected to a computer network and relaying communication between devices connected to different ports,
A frame transmission unit that generates a loop detection frame including identification information of the device itself, and periodically transmits the loop detection frame from an arbitrary port;
A loop detection processing unit that detects the occurrence of a loop when one of the plurality of ports receives the loop detection frame transmitted from the own device and blocks the port that transmitted the loop detection frame; ,
Display means for displaying that the occurrence of a loop is detected by the loop detection processing unit,
The loop detection processing unit transmits a block notification frame from the port before blocking the port that transmitted the loop detection frame, and the block notification transmitted from another device at any of the plurality of ports. When the frame is received, the switch device displays on the display means that the occurrence of a loop is detected in the other device. The switch device according to claim 1,
The loop detection processing unit, when receiving the block notification frame transmitted from another device at any one of the plurality of ports, blocks the port that has received the block notification frame. Switch device. The switch device according to claim 1 or 2,
The switch device, wherein the display means is an LED lamp provided for each port. A network system having a tree type or star type connection form,
A network system comprising a plurality of the switch devices according to any one of claims 1 to 3.

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