JP6362424B2 - 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 the 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 switching of the communication route is performed . When there is a need to be notified that a new active system is to be notified, the MAC address of the communication device possessed by the other base is used as the transmission source, and a relay apparatus other than the new active system is notified The route selected by the route selection device is changed by transmitting a packet whose destination is the MAC address of the route through the route selection device.
According to such a configuration, it is possible to switch communication paths without narrowing the bandwidth or incurring charges.

Further, the present invention is characterized in that when the relay device learns the MAC address of a communication device arranged at the other base, the MAC address is supplied to the other relay device to be learned. To do.
According to such a configuration, it is possible to save time and effort for a network administrator to manually input a MAC address.

Further, the present invention is characterized in that the MAC address assigned to itself is supplied to other relay apparatuses to be learned, and learning is performed by receiving the supply of the MAC address assigned to the other relay apparatuses.
According to such a configuration, it is possible to save time and effort for a network administrator to manually input a MAC address.

In the present invention, packets having the MAC address assigned to themselves as a transmission source and the MAC address assigned to another relay device as a transmission destination are mutually transmitted between the relay devices via the route selection device. It is characterized by doing.
According to such a configuration, occurrence of flooding can be prevented.

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 prevent the packet from being transferred to another base and narrowing the bandwidth or charging.

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 an 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 a communication device arranged in the base, the switching of the communication route is performed . When there is a need to be notified that a new active system is to be notified, the MAC address of the communication device possessed by the other base is used as the transmission source, and a relay apparatus other than the new active system is notified The route selected by the route selection device is changed by transmitting a packet whose destination is the MAC address of the route through the route selection device.
According to such a configuration, it is possible to switch communication paths without narrowing the bandwidth or incurring charges.

  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 table stored in each communication apparatus of the communication system shown in FIG. It is a figure for demonstrating the operation | movement which a gateway exchanges a MAC address. It is a figure which shows the state of the table after the operation | movement shown in FIG. It is a figure which shows the state from which a packet is transmitted toward a server from a client. It is a figure which shows the state of the table after the operation | movement shown in FIG. It is a figure which shows the state of the table after the operation | movement shown in FIG. It is a figure for demonstrating the synchronous process performed after the operation | movement of FIG. It is a figure which shows the state of the table after the operation | movement shown in FIG. It is a figure for demonstrating the operation | movement which mutually transmits a packet between gateway X and Y. FIG. It is a figure which shows the state of the table after the operation | movement shown in FIG. It is a figure for demonstrating the switch notification from the standby system by the CPE to an active system. It is a figure for demonstrating an example of the signal for switching from a standby system to an active system. It is a figure which shows the state of the table after the operation | movement shown in FIG. It is a figure which shows the state which transmits the packet whose transmission source MAC address is "A". It is a figure which shows the state of the table after the operation | movement shown in FIG. FIG. 18 is a diagram illustrating an operation when a packet is transmitted from the server to the client after the table is updated to the state illustrated in FIG. 17. 2 is a diagram illustrating a configuration example in which a plurality of L2 switches are arranged at a base 10. FIG. It is a figure which shows the structural example which has the two bases 20 and 40 which oppose. It is a figure which shows the structural example by which three gateways are arrange | positioned in the base 10. FIG.

  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, a server 14, and a communication path 15. doing. 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 gateway X and the gateway Y are connected by a communication path 15, and information can be exchanged via the communication path 15. In the example of FIG. 1, the communication path 15 is represented as a path that physically connects the gateway X and the gateway Y, but may be configured as a path that logically connects these. For example, it can be configured as a logical path via the L2 switch 13 (or a logical path via the communication paths 31 and 32). 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 an initial state of the learning table for relay stored in the gateway X, the gateway Y, and the L2 switch 13 is shown in FIG. FIG. 3A shows an example of a table stored in the gateway X. In this example, the gateway X has a relay learning table, a synchronization learning table, and a synchronization destination table. Here, the relay learning table is a table that stores the MAC address of the communication device in association with the 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. The synchronization learning table is a table for synchronizing the connection destinations connected via the communication paths 31 and 32 in which the gateways X and Y are made redundant, and the interface, the synchronization ID, and the MAC address are associated with each other. Stored. In the example of FIG. 3A, the interface “IF11” and the synchronization ID “0001” are stored in association with each other as an initial value, and the MAC address is empty “−”. The synchronization destination table is a table for storing the other party to be synchronized, and stores the MAC address and the interface in association with each other.

  FIG. 3B shows a table stored in the gateway Y. Similarly to the gateway X, the gateway Y also has a relay learning table, a synchronization learning table, and a synchronization destination table. The synchronization learning table stores the interface “IF21” and the synchronization ID “0001” in association with each other as an initial value, and the MAC address is empty “−”. Further, the relay learning table and the synchronization destination table are in an empty “-” state.

  FIG. 3C shows a table included in the L2 switch 13. In the example of FIG. 3C, the L2 switch 13 has a relay learning table. Similar to the gateways X and Y, the relay learning table stores MAC addresses and interfaces in association with each other. In the example of FIG. 3C, the MAC address “B” and the interface “IF33” are stored in the relay learning table in association with each other.

  Assume 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) in the case where the table of each device is in the state shown in FIG. Then, at the timing T1 shown in FIG. 2, as shown in FIG. 4, a process of exchanging MAC addresses between the gateway X and the gateway Y is executed. More specifically, the gateway X supplies the MAC address “X” of the interface IF 12 connected to the L2 switch 13 to the gateway Y via the communication path 15, and the gateway Y connects to the interface IF 22 connected to the L2 switch 13. Is provided to the gateway X via the communication path 15. The gateways X and Y update the table based on the supplied MAC address (P1 and P2 in FIG. 2). More specifically, the gateways X and Y store the supplied MAC addresses in the synchronization destination table in association with the interface connected to the L2 switch 13. As a result, as shown in FIG. 5A, the MAC address “Y” and the interface “IF12” are stored in the synchronization destination table of the gateway X in association with each other. As shown in FIG. 5B, the synchronization destination table of the gateway Y stores the MAC address “X” and the interface “IF22” in association with each other.

  Next, as shown in FIG. 6, when a packet is transmitted from the client 23 to the server 14 (see timing T2 in FIG. 2), this packet is received by the gateway X and transferred to the L2 switch 13. Further, the gateway X updates the table (P3). More specifically, since the gateway X has received the packet with the transmission destination MAC address “A” from the interface IF11, as shown in FIG. 7A, the gateway X has the MAC address “A” and the interface in the relay learning table. “IF11” is stored in association with each other. Further, as shown in FIG. 7A, the gateway X associates the MAC address “A” with the interface “IF11” and the synchronization ID “0001” stored as initial values in the synchronization learning table. Store. Here, the synchronization ID is a unique identifier that is given to an interface for which information regarding the MAC address is to be synchronized between devices.

  Next, the L2 switch 13 receives the packet transferred from the gateway X, and updates the table based on this packet (P4). More specifically, since the L2 switch 13 has received the packet with the transmission destination “A” from the interface IF 31, as shown in FIG. 8C, the MAC address “A” and the interface “ “IF31” is stored in association with each other.

  Next, at the timing T3 in FIG. 2, the gateway X executes a synchronization process for synchronizing the synchronization learning table with the gateway Y as shown in FIG. More specifically, the gateway X acquires information stored in the synchronization learning table and supplies the information to the gateway Y. The gateway Y updates its own learning table for synchronization. As a result, as shown in FIG. 10B, the MAC address “A” for the interface “IF21” and the synchronization ID “0001” stored as initial values in the gateway Y synchronization learning table. Are stored in association with each other.

  Next, at timings T4 and T5 in FIG. 2, the gateways X and Y transmit packets to each other as shown in FIG. In the example of FIG. 11, the gateway X refers to the synchronization destination table shown in FIG. 10A, and the MAC address of the transmission destination (DST) is “Y” and the MAC address of the transmission source (SRC) is “X”. Are transmitted to the L2 switch 13 via the interface IF12. Further, the gateway Y refers to the synchronization destination table shown in FIG. 10B, and sends a packet with the destination MAC address “X” and the source MAC address “Y” to the L2 via the interface IF22. Transmit to the switch 13. A packet transmitted by the gateway X is transmitted to the gateway Y via the L2 switch 13, and a packet transmitted by the gateway Y is transmitted to the gateway X via the L2 switch 13. Thereby, the L2 switch 13 performs learning by relaying these packets, and updates the table based on the learning result (see P6 in FIG. 2). As a result, in the relay learning table of the L2 switch 13, as shown in FIG. 12C, the MAC address “X” and the interface “IF31” are stored in association with each other, and the MAC address “Y” and the interface are stored. “IF32” is stored in association with each other. Further, since the gateway X receives the packet whose source MAC address is “Y” from the interface IF12, as shown in FIG. 12A, the MAC address “Y” and the interface “IF12” are stored in the relay learning table. Are stored in association with each other (see P7 in FIG. 2). Furthermore, since the gateway Y receives the packet whose source MAC address is “X” from the interface IF22, as shown in FIG. 12B, the MAC address “X” and the interface “IF22” are stored in the relay learning table. Are stored in association with each other (see P8 in FIG. 2).

  When the update of the table is completed by the above operation, the packet with the transmission destination MAC address “B” transmitted from the client 23 to the server 14 is transmitted to the L2 switch 13 via the CPE 21, the communication path 31, and the gateway X. To be supplied. The L2 switch 13 receives this packet, refers to the relay learning table, and outputs it from the interface “IF33” associated with the MAC address “B”. As a result, the server 14 receives this packet. On the other hand, a packet with a destination MAC address “A” transmitted from the server 14 to the client 23 is first supplied to the L2 switch 13. The L2 switch 13 inputs this packet from the interface IF 33, refers to the relay learning table, and outputs it from the interface “IF 31” associated with the MAC address “A”. The packet output from the IF 31 is input from the interface IF12 of the gateway X, and the gateway X refers to the relay learning table and outputs from the interface “IF11” associated with the MAC address “A”. A packet output from the interface IF 11 is received by the client 23 via the communication path 31 and the CPE 21. Such an operation enables communication between the client 23 and the server 14.

  Next, it is assumed that a failure has occurred in the communication path 31 used as the active system. 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. 13, 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 T6. 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. 14 can be used. FIG. 14 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. 14 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 P9 shown in FIG. More specifically, the gateway Y first refers to the MAC address “A” and the interface “IF21” stored in the synchronization learning table, and the MAC address “A” and the interface “IF21” with respect to the relay learning table. "Is stored in association with each other. As a result, the gateway Y table is in the state shown in FIG.

  Next, the gateway Y obtains “A”, which is the MAC address of the client 23 arranged at the base 20, from the synchronization learning table, and also the MAC address of another gateway X arranged at the base 10 from the synchronization destination table. "X" which is is acquired. Then, as shown in FIG. 16, the transmission source (SRC: Source) MAC address is set to “A” (the MAC address of the communication device existing at the end of the communication path that is newly used), and the transmission destination (DST: Destination). ) Is generated as a packet of “X” which is the MAC address of the other gateway X existing at the base 10, and the interface IF22 to which the L2 switch 13 is connected with reference to the synchronization destination table at the timing T7 shown in FIG. Output from. Here, in the normal time, the source MAC address of the packet transmitted by the gateway Y should be “Y”, but in the present embodiment, a new active system is newly added to the packet transmitted at this time. The MAC address “A” of the communication device (client 23) existing ahead of the communication path 32 is added with reference to the learning table for synchronization.

  When a packet as shown in FIG. 16 is transmitted from the gateway Y, the L2 switch 13 receives this packet via the interface IF 32. Since the destination MAC address of the received packet is “X”, the L2 switch 13 refers to the relay learning table shown in FIG. 5C, and sends this packet to the gateway X via the interface IF31. Forward. Further, the L2 switch 13 executes a table update process P10 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. As a result, the packet having the transmission destination MAC address “A” received by the L2 switch 13 is output from the interface IF 32 thereafter.

  The gateway X that has received the packet from the L2 switch 13 executes the table update process P11 as shown in FIG. More specifically, the gateway X recognizes that the transmission source MAC address of the received packet is “A” and the received interface is “IF12”. Next, in the relay learning table at that time, as shown in FIG. 15A, the MAC address “A” is associated with the interface “IF11”, and these do not match. As shown in FIG. 17A, the interface associated with the MAC address “A” in the relay learning table 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.

  After the above processing is executed and the relay learning table is updated to the state of FIG. 17, as shown in FIG. 18, 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. 17C, 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. 17B, 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. 16, the gateway Y newly used as the active system is connected to the communication path 32. A packet having the transmission source of the MAC address (“A”) of the device (client 23) is transmitted to gateway X, which is another gateway in the same base 10. Thereby, the relay learning table of the apparatus in the base 10 can be rewritten reliably. In this 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 such a packet is transmitted from the base 20 side. , It is possible to prevent the bandwidth from being limited or charged.

  Further, in this embodiment, when one gateway learns the MAC address of the client 23 arranged at the base 20, this MAC address is supplied to the other gateway for learning. For example, it is possible to omit the time and effort for the person to set manually.

  In the present embodiment, the gateways X and Y learn by exchanging the MAC addresses assigned to the interfaces connected to the L2 switch 13 with each other. However, the trouble of manually setting can be omitted, for example.

  Further, in the present embodiment, the gateways X and Y use a MAC address assigned to the gateway as a transmission source and a packet having a MAC address assigned to another gateway as a transmission destination between the gateways via the L2 switch 13. Since the transmissions are mutually transmitted, it is possible to prevent the occurrence of flooding due to the broadcast being executed.

(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, the case where one L2 switch 13 is arranged at the base 10 has been described as an example. However, two or more L2 switches may be arranged. FIG. 19 shows an example in which three L2 switches 13, 16, and 17 are arranged. More specifically, in the example of FIG. 19, the L2 switch 16 is added between the gateway X and the L2 switch 13, and the L2 switch 17 is added between the gateway Y and the L2 switch 13. The present invention can also be applied to such a configuration. Thus, when the present invention is applied to the embodiment shown in FIG. 19, the MAC address of the transmission source from the gateway Y is “A” and the MAC address of the transmission destination is “A” as shown in FIG. When the packet “X” is transmitted, not only the L2 switch 13 but also the L2 switches 16 and 17 can learn the relay direction based on this packet. More specifically, since the relay learning table of the L2 switch 17 stores the MAC address “A” and the interface “IF71” in association with each other, the packet (transmission destination) transmitted from the server 14 to the client 23 is stored. The packet having the MAC address “A”) is input from the interface IF 33 of the L2 switch 13 and output from the interface IF 32 based on the relay learning table shown in FIG. The L2 switch 17 inputs this packet from the interface IF 72 and, as described above, refers to the relay learning table in which the MAC address “A” and the interface “IF 71” are stored in association with each other, and outputs from the interface IF 71. . The gateway Y outputs this packet from the interface IF 21 with reference to the relay learning table shown in FIG. The packet output from the interface IF 21 is received by the client 23 via the communication path 32, the CPE 21, and the LAN 22. That is, even when two or more L2 switches are arranged, the communication path can be switched reliably.

  Further, in the embodiment shown in FIG. 1, the opposing base is configured by only the base 20, but two or more opposing bases may be provided. FIG. 20 shows a configuration example having two opposing bases. In this example, a base 40 is added to FIG. Further, a communication path 51 is added between the base 40 and the gateway Y, and a communication path 52 is added between the base 40 and the gateway X. In such a configuration, information about the MAC address “B” is added to the gateway X relay learning table and the synchronization learning table, and the MAC address “B” is also added to the gateway Y relay learning table and the synchronization learning table. Information about is added. Similarly, information regarding the MAC address “B” is added to the relay learning table of the L2 switch 13. With such a configuration, it is possible to switch communication paths as described above even when the number of bases increases. In the embodiment shown in FIG. 20, for example, when the gateway X is used as the active system, when only the CPE 41 switches the active system from the gateway X to the gateway Y, the client 43 of the gateway X in the conventional technology. Since the destination relay destination remains in the state of CPE 41, there is a problem that communication via the client 23, CPE 21, gateway X, and CPE 41 is interrupted at the time of switching. However, in the present embodiment, when the CPE 41 switches the active system to the gateway Y, the gateway Y transmits a packet with the source MAC address “C” to the gateway X via the L2 switch 13. The packet that has reached the gateway X from the client 23 via the CPE 21 is transmitted from the gateway X via the L2 switch 13 and the gateway Y to the client 43 via the CPE 41. Can be resolved.

  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. 21 shows a configuration example in the case where two standby systems exist. In the example of FIG. 21, a communication path 33 and a gateway Z are newly added. In such a configuration, when the active system is switched, the gateway that newly becomes the active system has the source MAC address “A” and the destination MAC address of the other two gateways. Packets that are the MAC addresses of the two gateways may be transmitted. In addition, the gateway that becomes the backup system is connected to the gateway that becomes the backup system by not transferring the packet to the base 20 after receiving the packet having the transmission source MAC address “A”. Packets can be prevented 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 packet shown in FIG. 16 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, for example, as shown in FIG. 4, the MAC addresses are exchanged between the gateways X and Y. However, for example, they may be stored in advance in the Config information.

  Further, in the above embodiment, only one server is arranged at the base 10, 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. 14 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.

  Alternatively, a virtual LAN segment may be formed by assigning a VLAN (Virtual LAN) ID (Identification) to the interface of the L2 switch 13. For example, a common VLAN ID is assigned to a plurality of communication devices connected to the L2 switch 13 to group the communication devices, and a VLAN is realized by limiting packet transmission within each group. be able to. When configuring such a VLAN, the VLAN ID is added to the table shown in FIG. 3 or the like and stored, and when exchanging the MAC address, the VLAN ID is also exchanged. Thus, the present invention can be applied to a communication system including a VLAN.

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 (6)

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 becomes necessary to switch the communication path and it is notified that the communication system is to be newly used, the MAC address of the communication device of the other base is used as the transmission source, and notification that the communication system is newly used is notified. A relay device, wherein a route selected by the route selection device is changed by transmitting a packet whose destination is a MAC address of a relay device other than the relay device via the route selection device.   2. The MAC address of a communication device arranged at the other base is learned by supplying the MAC address to another relay device when the relay device learns the MAC address. Relay device.   The MAC address assigned to itself is supplied to another relay device to be learned, and the MAC address assigned to the other relay device is supplied for learning. Relay device.   A packet having a MAC address assigned to itself as a transmission source and a MAC address assigned to another relay device as a transmission destination is transmitted between the relay devices via the route selection device. The relay device according to claim 3.   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. 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 becomes necessary to switch the communication path and it is notified that the communication system is to be newly used, the MAC address of the communication device of the other base is used as the transmission source, and notification that the communication system is newly used is notified. A relay of a relay device, wherein the route selected by the route selection device is changed by transmitting, via the route selection device, a packet whose destination is a MAC address of a relay device other than the relay device. Method.

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