JP6356047B2 - Relay system and switch device - Google Patents

Description

  The present invention relates to a relay system and a switch device, for example, a relay system and a switch device in which a link aggregation group is set across two switch devices.

  For example, Patent Document 1 discloses a communication system including two switch devices in which a device-to-device link aggregation group (hereinafter abbreviated as LAG) is set. In the system, when one switch device receives a frame at a port in which a device-to-device LAG is set and relays the frame to the other switch device, the LAG of the received port is included in the frame as the received port identifier. Add an identifier.

JP 2014-107592 A

  For example, as a redundancy method, as shown in Patent Document 1, two switch devices are connected to each other via a bridge port, and LAGs are connected to a plurality of ports including the respective ports of the two switch devices. A method of setting is known. In the redundancy method, unlike a general LAG set by one switch device, a LAG is set across two switch devices. For this reason, in addition to the effects obtained by general LAG such as redundancy for communication line failures and expansion of communication bandwidth, it is possible to realize redundancy for switch device failures.

  In this specification, such a LAG across devices is referred to as a multi-chassis link aggregation group (hereinafter abbreviated as MCLAG). A group of two switch devices in which MCLAG is set is called an MCLAG switch. Furthermore, the other switch device when the other is viewed from one of the two switch devices is referred to as a peer device.

  In general, when a frame is received at a port, the switch device learns the transmission source MAC address of the frame in the address table in association with the port. For this reason, for example, when a frame is received at a port, the switch device adds a port identifier representing the received port (hereinafter referred to as a reception port identifier) to the frame. On the other hand, the MCLAG switch logically manages a plurality of ports in which MCLAG is set as one port. For this reason, the MCLAG switch needs to use an MCLAG identifier instead of an actual port identifier as a reception port identifier for a frame received at a port in which MCLAG is set (hereinafter referred to as an MCLAG port). .

  Specifically, for example, it is assumed that one switch device configuring the MCLAG switch receives a frame at the MCLAG port and relays the frame to the peer device. In this case, the peer device needs to use the MCLAG identifier instead of the port identifier of the bridge port as the reception port identifier even though the frame is actually received by the bridge port.

  As one of the implementation methods, for example, a method disclosed in Patent Document 1 can be cited. When this method is used, one switch device constituting the MCLAG switch adds an MCLAG identifier when relaying a frame received at the MCLAG port to the peer device, and the peer device receives the MCLAG identifier. Treat it as a port identifier. However, in this case, since the reception port identifier is disguised with an MCLAG identifier different from the port (bridge port) that actually received the frame, there is a possibility that the frame may be folded when a failure occurs in the MCLAG switch. Something has been found by the present inventors.

  The present invention has been made in view of such circumstances, and one of its purposes is to provide a relay system and a switch device capable of preventing the frame from being folded back.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  Of the inventions disclosed in the present application, the outline of a typical embodiment will be briefly described as follows.

  The relay system according to the present embodiment includes first and second switch devices. Each of the first and second switch devices has a plurality of ports including a bridge port and a first MCLAG port in which a device-to-device LAG is set, and is connected to each other via a communication line via the bridge port. Is done. Each of the first and second switching devices includes an MCLAG table, an address table, a relay processing unit, a first identifier adding unit, and a loopback prohibiting unit. The MCLAG table holds the first MCLAG port in association with the first MCLAG identifier. The address table holds a correspondence relationship between a port identifier representing a port or an MCLAG identifier associated with the port and a MAC address existing ahead of the port. When the relay processing unit receives a frame at the first MCLAG port and relays the frame to the bridge port, the relay processing unit adds the first MCLAG identifier to the frame. Further, when the relay processing unit receives a frame with the first MCLAG identifier added from the peer device at the bridge port, the relay processing unit associates the transmission source MAC address of the frame with the first MCLAG identifier added to the frame. It learns from the address table and relays the frame to the destination port. The first identifier adding unit further adds a first identifier to the frame to which the first MCLAG identifier is added. The loopback prohibiting unit prohibits relaying of the frame when the destination port of the frame to which the first identifier is added is a bridge port.

  The effects obtained by the representative embodiments of the invention disclosed in this application will be briefly described. In the relay system including the MCLAG switch, it is possible to prevent the frame from being folded.

In the relay system by Embodiment 1 of this invention, it is the schematic which shows the structural example. (A) And (b) is explanatory drawing which shows the operation example used as the premise at the time of transferring a user frame in the relay system of FIG. FIG. 3 is an explanatory diagram illustrating an operation example when a failure occurs in the relay system of FIG. 1. FIG. 2 is a schematic diagram illustrating a configuration example of each switch device configuring an MCLAG switch in the relay system of FIG. 1. (A) is the schematic which shows the structural example of the MCLAG table in FIG. 4, (b) is the schematic which shows the structural example of the address table in FIG. FIG. 5 is an explanatory diagram showing an operation example of the switch device of FIG. 4. FIG. 5 is an explanatory diagram showing an operation example of the switch device of FIG. 4. It is the schematic which shows the structural example in the switch apparatus by Embodiment 2 of this invention. FIG. 9 is an explanatory diagram showing an operation example of the switch device of FIG. 8. FIG. 5 is an explanatory diagram showing an operation example when a failure occurs when the relay system studied as a premise of the present invention does not include the first identifier adding unit and the loopback prohibiting unit of FIG. 1.

  In the following embodiment, when it is necessary for the sake of convenience, the description will be divided into a plurality of sections or embodiments. However, unless otherwise specified, they are not irrelevant, and one is the other. Some or all of the modifications, details, supplementary explanations, and the like are related. Further, in the following embodiments, when referring to the number of elements (including the number, numerical value, quantity, range, etc.), especially when clearly indicated and when clearly limited to a specific number in principle, etc. Except, it is not limited to the specific number, and may be more or less than the specific number.

  Further, in the following embodiments, the constituent elements (including element steps and the like) are not necessarily indispensable unless otherwise specified and apparently essential in principle. Needless to say. Similarly, in the following embodiments, when referring to the shapes, positional relationships, etc. of the components, etc., the shapes are substantially the same unless otherwise specified, or otherwise apparent in principle. And the like are included. The same applies to the above numerical values and ranges.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment, and the repetitive description thereof will be omitted.

(Embodiment 1)
<Outline of relay system>
FIG. 1 is a schematic diagram showing a configuration example of a relay system according to Embodiment 1 of the present invention. The relay system shown in FIG. 1 includes an MCLAG switch MCLAGSW composed of two switch devices (first and second switch devices) SW1 and SW2, and a plurality (two in this case) of communication devices 10 [1], 10 [2]. Each of the switch devices SW1 and SW2 is an L2 switch that performs a relay process for Layer 2 (L2), an L3 switch that performs a relay process for Layer 3 (L3), or the like. In this embodiment, a case where an L2 switch is used is taken as an example.

  Each of the switch devices (first and second switch devices) SW1 and SW2 has a plurality of ports including a bridge port Pb and a plurality (here, two) of MCLAG ports Pm1 and Pm2. An LAG across devices is set in each of the MCLAG ports Pm1 and Pm2. The switch devices SW1 and SW2 are connected to each other via the communication line 12 via the bridge port Pb. The communication line 12 may be composed of an Ethernet (registered trademark) line or a dedicated line.

  Here, each of the switching devices SW1 and SW2 has two MCLAG ports Pm1 and Pm2, but may have three or more MCLAG ports. You may have a port for MCLAG. Further, each of the switch devices SW1 and SW2 is not limited to the MCLAG port, and may have a general port in which no device-to-device LAG is set.

  Each of the communication devices 10 [1] and 10 [2] is, for example, an information processing device such as a server device or a switch device such as an L2 switch. Each of the communication devices 10 [1] and 10 [2] has ports Pu1 and Pu2. The MCLAG ports (first MCLAG ports) Pm1 of the switch devices SW1 and SW2 are connected to the ports Pu1 and Pu2 of the communication device 10 [1] via the communication line 11, respectively. Similarly, the MCLAG ports (second MCLAG ports) Pm2 of the switch devices SW1 and SW2 are connected to the ports Pu1 and Pu2 of the communication device 10 [2] via the communication line 11, respectively. The ports Pu1 of the communication devices 10 [1] and 10 [2] are connected to the switch device SW1 side, and the port Pu2 is connected to the switch device SW2 side. The communication line 11 is configured by an Ethernet line, for example.

  Here, each of the switching devices SW1 and SW2 sets a common LAG (that is, MCLAG) for the MCLAG port of the own device and the MCLAG port of the peer device. For example, the switch device SW1 sets a common MCLAG1 for the MCLAG port Pm1 of the own device (SW1) and the MCLAG port Pm1 of the peer device (SW2), and the switch device SW2 is also the MCLAG of the own device (SW2). A common MCLAG1 is set for the port Pm1 and the MCLAG port Pm1 of the peer device (SW1). Similarly, the switching devices SW1 and SW2 set the common MCLAG2 to the mutual MCLAG port Pm2.

  On the other hand, the communication device 10 [1] sets MCLAG1 to the ports Pu1 and Pu2, and the communication device 10 [2] sets MCLAG2 to the ports Pu1 and Pu2. Here, each of the communication devices 10 [1] and 10 [2] sets the MCLAG to the ports Pu1 and Pu2, but in practice, a normal LAG may be set, and in particular, the MCLAG. It is not necessary to distinguish between LAG and LAG. That is, the ports Pu1 and Pu2 of the communication devices 10 [1] and 10 [2] may be LAG ports.

  In such a configuration, FIG. 1 shows, as an example of the operation method of the MCLAG switch MCLAGSW, a method of setting an active ACT or a standby SBY for each MCLAG as a member port for the MCLAG. . In this example, in MCLAG1, the MCLAG port Pm1 of the switch device SW1 is set to active ACT, and the MCLAG port Pm1 of the switch device SW2 is set to standby SBY. On the other hand, in MCLAG2, the MCLAG port Pm2 of the switch device SW1 is set to standby SBY, and the MCLAG port Pm2 of the switch device SW2 is set to active ACT.

  When there is no failure, the MCLAG port set to active ACT is controlled to a transmission / reception permission state FW that permits both transmission and reception. On the other hand, the MCLAG port set to the standby SBY is controlled to a transmission prohibited state TBK in which transmission is prohibited and reception is permitted. As a result, for example, a frame from the MCLAG switch MCLAGSW toward the communication device 10 [1] is always transmitted from the MCLAG port Pm1 of the switch device SW1. A frame from the MCLAG switch MCLAGSW to the communication device 10 [2] is always transmitted from the MCLAG port Pm2 of the switch device SW2. On the other hand, a frame from the communication device 10 [1] or the communication device 10 [2] toward the MCLAG switch MCLAGSW is transmitted from both (LAG ports) Pu1 and Pu2.

  Here, for example, when a failure occurs in the MCLAG port Pm1 of the switch device SW1, the switching operation at the time of failure is performed in the MCLAG switch MCLAGSW. Specifically, in MCLAG1, the MCLAG port Pm1 of the switch device SW2 is controlled to the transmission / reception permitted state FW, and the MCLAG port Pm1 of the switch device SW1 is controlled to the transmission / reception prohibited state that prohibits both transmission and reception, for example. The

  The operation method of the MCLAG switch MCLAGSW is not limited to such a method, and various methods can be used. For example, there is a method in which the MCLAG port for transmitting a frame is equally distributed to the two switch devices SW1 and SW2 based on the distributed ID or the like.

  In addition, FIG. 1 shows a schematic configuration example of a main part of the switching devices SW1 and SW2. Here, each of the switching devices SW1 and SW2 includes a frame processing unit 13 that performs frame processing, an address table FDB, an MCLAG table 14, and a first identifier adding unit 15. The MCLAG table 14 holds the MCLAG port (for example, the first MCLAG port Pm1) in association with the MCLAG identifier (for example, the first MCLAG identifier {MCLAG1}). {MCLAG1} represents an identifier (ID) of MCLAG1, and hereinafter, in this specification, {AA} represents an identifier of “AA”.

  The address table FDB holds a correspondence relationship between a port identifier representing a port or an MCLAG identifier associated with the port and a MAC address existing ahead of the port. The frame processing unit 13 includes a relay processing unit 16 and a loopback prohibiting unit 17. When receiving a frame at the port, the relay processing unit 16 relays the frame based on the address table FDB or the MCLAG table 14 in addition. Although the details will be described later, the loopback prohibiting unit 17 and the first identifier adding unit 15 perform various processes for preventing a frame received at the bridge port Pb from being looped back to the bridge port Pb.

  FIG. 2A and FIG. 2B are explanatory diagrams illustrating an operation example that is a premise when transferring a user frame in the relay system of FIG. 2A and 2B, it is assumed that the communication devices 10 [1] and 10 [2] have MAC addresses MA1 and MA2, respectively. 2A and 2B show an example of a frame transfer path from the communication device 10 [1] to the communication device 10 [2].

  First, in FIG. 2A and FIG. 2B, the communication device 10 [1] transmits one of the ports (LAG ports) Pu1 and Pu2 based on a predetermined distribution rule when transmitting a user frame. Select one. The communication device 10 [1] selects the port Pu1 in FIG. 2A and the port Pu2 in FIG. 2B.

  In FIG. 2A, the communication device 10 [1] transmits the user frame UF12a including the source MAC address MA1 and the destination MAC address MA2 from the selected port Pu1. The switch device SW1 (specifically, the relay processing unit 16) receives the user frame UF12a at the MCLAG port Pm1, and learns the source MAC address MA1 in association with the MCLAG identifier {MCLAG1} in the address table FDB.

  Further, the switch device SW1 (relay processing unit 16) searches the address table FDB and acquires an identifier of the destination port corresponding to the destination MAC address MA2 (hereinafter referred to as a destination port identifier). Here, the destination port identifier is the MCLAG identifier {MCLAG2}. In FIG. 2A, among the MCLAG2 member ports, the MCLAG port Pm2 of the switch device SW1 is controlled to the transmission prohibited state TBK, and the MCLAG port Pm2 of the switch device SW2 is set to the transmission / reception permitted state FW. It is controlled. For this reason, the switching device SW1 relays the user frame UF12a to the bridge port Pb.

  Here, when the switch device SW1 (relay processing unit 16) receives the frame at the MCLAG port and relays the frame to the bridge port Pb, the switch device SW1 (relay processing unit 16) adds the reception port identifier SP to the frame. In the example of FIG. 2 (a), the switching device SW1 relays the user frame UF12a received at the MCLAG port (first MCLAG port) Pm1 to the bridge port Pb. Therefore, the MCLAG identifier (first MCLAG identifier) is assigned to the frame. Add {MCLAG1}.

  On the other hand, when the switch device SW2 (specifically, the relay processing unit 16) receives the frame with the reception port identifier SP from the peer device (SW1) at the bridge port Pb, the transmission source MAC of the frame is transmitted. The address is learned in the address table FDB in association with the reception port identifier SP added to the frame. In the example of FIG. 2A, the switching device SW2 associates the transmission source MAC address MA1 of the user frame UF12a received at the bridge port Pb with the MCLAG identifier {MCLAG1} added to the frame, and the address table FDB. To learn.

  Further, when the switch device SW2 (relay processing unit 16) receives a frame to which the reception port identifier SP is added at the bridge port Pb, the switch device SW2 searches the address table FDB and determines the destination port based on the search result. . In the example of FIG. 2A, the switching device SW2 acquires a destination port identifier (that is, MCLAG identifier {MCLAG2}) corresponding to the destination MAC address MA2 of the user frame UF12a. Since the MCLAG port Pm2 of the switching device SW2 is controlled to the transmission / reception permitted state FW, the switch device SW2 determines the destination port as the MCLAG port Pm2, and relays the user frame UF12a to the MCLAG port Pm2.

  Next, in FIG. 2B, the communication device 10 [1] transmits the user frame UF12b including the transmission source MAC address MA1 and the destination MAC address MA2 from the selected port Pu2. The switching device SW2 (specifically, the relay processing unit 16) receives the user frame UF12b at the MCLAG port Pm1, and learns the source MAC address MA1 in association with the MCLAG identifier {MCLAG1} in the address table FDB.

  In addition, the switching device SW2 (relay processing unit 16) searches the address table FDB and acquires a destination port identifier (that is, MCLAG identifier {MCLAG2}) corresponding to the destination MAC address MA2. Since the MCLAG port Pm2 of the switch device SW2 is controlled to the transmission / reception permitted state FW, the switching device SW2 determines the destination port as the MCLAG port Pm2, and relays the user frame UF12b to the MCLAG port Pm2.

<< Operations and problems when a failure occurs in a relay system (prerequisite) >>
FIG. 10 is an explanatory diagram illustrating an operation example when a failure occurs when the relay system studied as a premise of the present invention does not include the first identifier addition unit and the loopback prohibition unit of FIG. In the example of FIG. 10, a failure has occurred in the communication line 11 connected to the MCLAG port Pm2 of the switch device SW2 while the user frame UF12a shown in FIG. Step S201).

  In response to this, the switching device SW2 changes the control state of the MCLAG port Pm2 of its own device from the transmission / reception permitted state FW to a transmission / reception prohibited state BK that prohibits both transmission and reception, for example (step S202). Further, the switching device SW1 receives the control frame for MCLAG including the failure information from the switching device SW2 at the bridge port Pb, and transmits and receives the control state of the MCLAG port Pm2 of the own device from the transmission prohibited state TBK. It changes to permission state FW (step S203).

  However, a certain period may be required between step S202 and step S203. During this period, the switching device SW1 relays the user frame UF12a to which the reception port identifier SP (MCLAG identifier {MCLAG1}) is added to the bridge port Pb. The switch device SW2 receives the user frame UF12a at the bridge port Pb. The switch device SW2 (specifically, the relay processing unit 16) learns the address table FDB and searches the address table FDB similarly to the case of FIG. The identifier {MCLAG2}) is acquired.

  Here, in FIG. 10, unlike the case of FIG. 2A, the MCLAG port Pm2 of the switch device SW2 is controlled to the transmission / reception prohibited state BK in step S202. For this reason, the switching device SW2 (relay processing unit 16) changes the destination port identifier DP of the user frame UF12a to the port identifier {Pb} of the bridge port Pb (step S204).

  On the other hand, the reception port identifier SP of the user frame UF12a is the MCLAG identifier {MCLAG1} added by the switching device SW1. In this case, the destination port identifier DP and the reception port identifier SP do not match. For this reason, the switching device SW2 (relay processing unit 16) permits the relay of the user frame UF12a to the bridge port Pb, and as a result, the frame is folded (step S205). In other words, the switching device normally has a function of prohibiting frame wrapping when the destination port identifier DP and the reception port identifier SP match. However, even if this function is used, it is possible to prevent frame wrapping. Can not.

  The switch device SW1 receives the frame returned by the switch device SW2 at the bridge port Pb. Here, if the process of step S203 is not completed, the switch device SW1 further wraps the frame in the same manner as the switch device SW2. Such frame folding may cause communication congestion between the bridge ports Pb.

<< Operation when a failure occurs in the relay system (first embodiment) >>
FIG. 3 is an explanatory diagram showing an operation example when a failure occurs in the relay system of FIG. In the example of FIG. 3, similarly to the case of FIG. 10, the communication line 11 connected to the MCLAG port Pm2 of the switching device SW2 in a state where the transfer of the user frame UF12a shown in FIG. Has failed (step S101).

  Accordingly, as in the case of FIG. 10, the switching device SW2 changes the control state of the MCLAG port Pm2 of the own device from the transmission / reception permitted state FW to, for example, the transmission / reception prohibited state BK (step S102). Also, the switching device SW1 changes the control state of the MCLAG port Pm2 of its own device from the transmission prohibited state TBK to the transmission / reception permitted state FW (step S103). In the period between step S102 and step S103, the switching device SW1 relays the user frame UF12a to which the reception port identifier SP (first MCLAG identifier {MCLAG1}) is added to the bridge port Pb. The switch device SW2 receives the user frame UF12a at the bridge port Pb.

  Here, the switching device SW2 (specifically, the first identifier adding unit 15) further adds the reception port identifier SP (first MCLAG identifier {MCLAG1}) transmitted from the switching device SW1 to the user frame UF12a. A second receiving port identifier (first identifier) SP2 is added (step S104). In the example of FIG. 3, when the first identifier adding unit 15 receives a frame with the MCLAG identifier added at the bridge port Pb, the first identifier adding unit 15 bridges the frame as the second receiving port identifier (first identifier) SP2. A port identifier {Pb} of the service port Pb is added.

  The switch device SW2 (specifically, the relay processing unit 16) learns the address table FDB in the same manner as in FIG. That is, the relay processing unit 16 learns the transmission source MAC address MA1 of the user frame UF12a in the address table FDB in association with the reception port identifier SP (first MCLAG identifier {MCLAG1}) added to the user frame UF12a.

  Further, in the case of FIG. 2A, the relay processing unit 16 searches the address table FDB to obtain the destination port identifier (that is, the MCLAG identifier {MCLAG2}). In FIG. 3, as in the case of FIG. 10, the MCLAG port Pm2 of the switch device SW2 is controlled to the transmission / reception prohibited state BK by step S102. Therefore, the switching device SW2 (relay processing unit 16) changes the destination port identifier DP of the user frame UF12a to the port identifier {Pb} (step S105).

  Here, the switching device SW2 (specifically, the loopback prohibiting unit 17), when the destination port of the frame to which the second reception port identifier (first identifier) SP2 is added is the bridge port Pb, Is prohibited (step S106). In the example of FIG. 3, when the destination port identifier DP and the second reception port identifier (first identifier) SP2 match, the loopback prohibiting unit 17 prohibits relaying of the frame, for example, discards the frame. .

  As described above, by using the method shown in FIGS. 1 and 3, it is possible to prevent the frame from being folded as described in FIG. 10, and to reduce the communication congestion that may occur between the bridge ports Pb. .

  Here, as an example of the operations of the first identifier adding unit 15 and the loopback prohibiting unit 17, the first identifier adding unit 15 adds the port identifier {Pb} as the first identifier SP2, and the loopback prohibiting unit 17 Frame relaying is prohibited when the destination port identifier DP and the first identifier SP2 match. However, the operations of the first identifier adding unit 15 and the folding prohibiting unit 17 are not necessarily limited to this, and can be changed as appropriate. For example, as another operation example, the first identifier adding unit 15 adds a 1-bit flag or the like as the first identifier SP2, and the loopback prohibiting unit 17 sets the destination port of the frame to which the flag is added as a bridge port. In the case of Pb, the relay of the frame may be prohibited.

  Although the description has been made on the assumption of the operation of FIG. 2A, the present invention is not necessarily limited to this. For example, even when the operation shown in FIG. 2B is assumed, the same problem as in FIG. 10 may occur. Specifically, when the control state of the MCLAG port Pm2 is changed as in FIG. 10 in the state of FIG. 2B, the switch device SW1 receives the frame from the switch device SW2 at the bridge port Pb. To do. Here, when the control state of the MCLAG port Pm2 of the switch device SW1 has not been changed yet, the switch device SW1 wraps the frame. Even in such a case, it is possible to prevent the frame from being folded by using the method shown in FIGS.

  In addition, the relay processing unit 16 of the MCLAG switch MCLAGSW normally switches the destination port according to a failure by taking the operation method as shown in FIGS. 1 to 3 as an example. Specifically, the relay processing unit 16, for example, when the destination of the frame received at the first MCLAG port of the own device is the MCLAG identifier of the second MCLAG port, the second MCLAG port that the own device and the peer device have If there is no failure, the frame is relayed to one of the second MCLAG ports of both devices. When the one second MCLAG port has a failure, the relay processing unit 16 relays the frame to the other second MCLAG port. As described above, the MCLAG switch MCLAGSW that switches the destination port according to the failure may cause the same problem as in FIG. 10, and the same effect can be obtained.

  Further, in the example of FIG. 3, when the switch device SW2 receives the user frame at the bridge port Pb, the switch device SW2 searches the address table FDB and determines the destination port based on the search result. On the other hand, a method is conceivable in which the switching device SW1 determines the destination port, adds the destination port identifier to the frame in addition to the reception port identifier SP, and relays the frame to the bridge port Pb.

  Specifically, when the relay processing unit 16 (here, the switching device SW1) relays the frame to which the reception port identifier SP is added to the bridge port Pb, the relay processing unit 16 (in this case, the switch device SW1) further adds the frame to the search result of the address table FDB. Based on the destination port identifier (here, MCLAG identifier {MCLAG2}) is added. Further, when the relay processing unit 16 (here, the switch device SW2) receives the frame with the destination port identifier from the peer device received by the bridge port Pb, the relay processing unit 16 (the switch device SW2) does not search the address table FDB and searches for the frame. The destination port is determined based on the destination port identifier.

  In this case, as in the case of FIG. 10, the relay processing unit 16 of the switch device SW2 uses the destination port identifier based on the destination port identifier (here, the MCLAG port Pm2) in the transmission / reception prohibited state BK. The identifier {Pb} is changed and the destination port is determined as the bridge port Pb. As a result, the same problem as in FIG. 10 may occur. Therefore, even in such a case, the problem of FIG. 10 can be solved by using the second reception port identifier (first identifier) SP2 as in the case of FIG.

<Configuration of switch device>
FIG. 4 is a schematic diagram illustrating a configuration example of each switch device configuring the MCLAG switch in the relay system of FIG. FIG. 5A is a schematic diagram showing an example of the structure of the MCLAG table in FIG. 4, and FIG. 5B is a schematic diagram showing an example of the structure of the address table in FIG. 4 includes a plurality of ports including MCLAG ports Pm1, Pm2 and a bridge port Pb, an interface unit 20, a frame processing unit 13, a processor unit CPU, an address table FDB, and an MCLAG table. 14. The plurality of ports may include general ports and the like.

  The interface unit 20 includes a transmission buffer and a reception buffer, and controls frame communication between the plurality of ports and the frame processing unit 13 or the processor unit CPU. When receiving the frame with the destination port identifier added, the interface unit 20 transmits the frame to the port corresponding to the destination port identifier via the transmission buffer. The interface unit 20 includes a failure detection unit 21 and a reception port identifier addition unit 22. The reception port identifier adding unit 22 includes a first identifier adding unit 15.

  The reception port identifier adding unit 22 adds a reception port identifier to the frame when the frame is received at any of the plurality of ports. However, if the receiving port identifier adding unit 22 does not include the first identifier adding unit 15, the receiving port identifier SP is normally received by the bridge port Pb in order to realize the function as the MCLAG switch. In this case, the reception port identifier is not added. On the other hand, as shown in FIG. 3, the first identifier adding unit 15 further receives the second reception port identifier (first output) when the frame to which the reception port identifier SP has already been added is received by the bridge port Pb. Identifier) SP2 is added.

  The failure detection unit 21 detects the presence / absence of a failure (link presence / absence) for each of a plurality of ports by hardware. For example, the failure detection unit 21 monitors the received optical signal level and detects the presence of link down when an abnormal state such as an insufficient optical signal level continues for a predetermined period. Alternatively, the failure detection unit 21 monitors the presence or absence of a link pulse signal generated in an idle state or the presence or absence of a data signal in a non-idle state from the received signal, and an abnormal state in which neither the link pulse signal nor the data signal is present. Is detected when the link is down for a predetermined period.

  As shown in FIG. 5A, the MCLAG table 14 holds MCLAG ports in association with MCLAG identifiers. The MCLAG table 14 also holds the control status of each MCLAG port here. In the example of FIG. 5A, the port identifier {Pm1} representing the MCLAG port Pm1 is associated with the MCLAG identifier {MCLAG1} and controlled to the transmission / reception permitted state FW. The port identifier {Pm2} representing the MCLAG port Pm2 is associated with the MCLAG identifier {MCLAG2} and is controlled to the transmission prohibited state TBK.

  As shown in FIG. 5B, the address table FDB is a correspondence between a port identifier representing a port or an MCLAG identifier associated with the port, and a MAC address and VLAN identifier (VID) existing ahead of the port. Hold. In the example of FIG. 5B, the MAC address MA1 is held in association with the VLAN identifier “xxx” and the MCLAG identifier {MCLAG1}, and the MAC address MA2 corresponds to the VLAN identifier “xxx” and the MCLAG identifier {MCLAG2}. It is kept attached. The VLAN identifier is appropriately determined by a port VLAN or a tag VLAN.

  The processor unit CPU includes a control frame processing unit 23 and a port control unit 24 configured by executing a program held in a storage unit (not shown). The control frame processing unit 23 generates and transmits various control frames. As one of the control frames, for example, there is an MCLAG control frame for periodically transmitting and receiving to / from a peer device via the bridge port Pb. By transmitting and receiving the control frame for MCLAG, fault information is shared and the existence of each switch device is confirmed.

  Further, as one of the control frames, for example, a control frame such as Ethernet OAM (Operations, Administration, and Maintenance) may be included. In Ethernet OAM, for example, communication with the outside of the apparatus can be monitored by periodically transmitting and receiving a control frame (test frame) called CCM (Continuity Check Message). Thereby, for example, it is possible to detect the presence or absence of a failure in each of the MCLAG ports Pm1 and Pm2.

  The port control unit 24 uses the MCLAG table based on the failure information from the failure detection unit 21, the failure information from the control frame processing unit 23, and the predetermined active ACT / standby SBY setting information. 14 determines the control state of each MCLAG port. Specifically, when the MCLAG port of the own apparatus has a failure, the port control unit 24 controls the MCLAG port to the transmission / reception prohibited state BK.

  Further, the port control unit 24 controls the MCLAG port to the transmission / reception permitted state FW when the MCLAG port of the own apparatus is set to active ACT when there is no failure. Further, when the MCLAG port of the own device is not faulty and is set to the standby SBY, the port control unit 24 determines the MCLAG port of the own device according to the presence or absence of the fault of the MCLAG port on the active ACT side. To control.

  Specifically, when there is no failure in the active ACT side MCLAG port, the port control unit 24 controls the MCLAG port of the own device to the transmission prohibited state TBK, and the active ACT side MCLAG port fails. If yes, the MCLAG port of the own device is controlled to the transmission / reception permitted state FW. Information on the presence / absence of a failure of the MCLAG port on the active ACT side is obtained by the above-described control frame for MCLAG.

  The frame processing unit 13 includes a relay processing unit 16 and a loopback prohibiting unit 17. As described with reference to FIGS. 2A and 2B, the relay processing unit 16 relays the frame based on the address table FDB when the frame is received at the port. Specifically, when the relay processing unit 16 receives a user frame at a port, the relay processing unit 16 associates the transmission source MAC address of the user frame with the VLAN identifier and the reception port identifier SP added to the user frame. To learn the address table FDB. The reception port identifier SP is added by the interface unit 20 of the own device or the peer device.

  Further, the relay processing unit 16 searches the address table FDB using the destination MAC address and VLAN identifier of the user frame as search keys, and acquires the destination port identifier. Here, when the destination port identifier is an MCLAG identifier, the relay processing unit 16 determines the control state of the MCLAG port of its own device that is a member port of the MCLAG identifier based on the MCLAG table 14.

  For example, when the control state of the MCLAG port of the own device is the transmission / reception permitted state FW, the relay processing unit 16 transmits the user frame to which the destination port identifier indicating the MCLAG port is added via the interface unit 20. Relay to the port. On the other hand, when the control state is the transmission prohibited state TBK, the relay processing unit 16 relays the user frame to which the port identifier {Pb} is added as the destination port identifier to the bridge port Pb via the interface unit 20. At this time, when the reception port identifier SP is an MCLAG identifier, the relay processing unit 16 adds the reception port identifier SP to the user frame.

  When the destination port identifier DP and the reception port identifier SP match, the loopback prohibition unit 17 prohibits the relay of the frame and discards the frame. In addition, even when the destination port identifier DP and the second reception port identifier (first identifier) SP2 match, the loopback prohibiting unit 17 prohibits relaying of the frame and discards the frame.

<Operation of switch device>
6 and 7 are explanatory diagrams showing an operation example of the switch device of FIG. 6 shows an operation example of the switch device SW1 of FIG. 3, and FIG. 7 shows an operation example of the switch device SW2 of FIG. First, in FIG. 6, the switching device SW1 receives the user frame UF12a including the source MAC address SA (here, MA1) and the destination MAC address DA (here, MA2) at the MCLAG port Pm1. The reception port identifier adding unit 22 adds a port identifier {Pm1} that is a reception port identifier SP to the user frame UF12a.

  Based on the MCLAG table 14, the relay processing unit 16 recognizes that the port identifier {Pm1} is associated with the MCLAG identifier {MCLAG1}, and associates the source MAC address MA1 with the MCLAG identifier {MCLAG1}. The table FDB is learned. Further, the relay processing unit 16 searches the address table FDB, and acquires the MCLAG identifier {MCLAG2} that is the destination port identifier DP corresponding to the destination MAC address MA2.

  Based on the MCLAG table 14, the relay processing unit 16 recognizes that the member port of its own device corresponding to the MCLAG identifier {MCLAG2} is controlled to the transmission prohibited state TBK, and sets the destination port identifier DP as the bridge port Pb. Port identifier {Pb}. Further, the relay processing unit 16 changes the reception port identifier SP added to the user frame UF12a from the port identifier {Pm1} to the MCLAG identifier {MCLAG1}. Then, the relay processing unit 16 transmits the user frame UF12a to which the destination port identifier DP and the reception port identifier SP are added to the interface unit 20 via the loopback prohibiting unit 17.

  At this time, the aliasing prohibition unit 17 does not match the destination port identifier DP ({Pb}) and the reception port identifier SP ({MCLAG1}), and the second reception port identifier (first identifier) SP2 is added. Therefore, the passage of the user frame UF12a is permitted. The interface unit 20 transmits the user frame UF12a to which the reception port identifier SP ({MCLAG1}) is added to the bridge port Pb based on the destination port identifier DP ({Pb}). At this time, the interface unit 20 deletes the destination port identifier DP added to the user frame UF12a.

  Next, in FIG. 7, the switching device SW2 receives the user frame UF12a to which the reception port identifier SP ({MCLAG1}) is added at the bridge port Pb. The first identifier adding unit 15 further adds a port identifier {Pb} that is a second reception port identifier (first identifier) SP2 to the user frame UF12a.

  The relay processing unit 16 learns the transmission source MAC address MA1 of the user frame UF12a in the address table FDB in association with the reception port identifier SP ({MCLAG1}). Further, the relay processing unit 16 searches the address table FDB, and acquires the MCLAG identifier {MCLAG2} that is the destination port identifier DP corresponding to the destination MAC address MA2.

  Based on the MCLAG table 14, the relay processing unit 16 recognizes that the member port of the own device corresponding to the MCLAG identifier {MCLAG2} is controlled to the transmission / reception prohibited state BK. That is, with step S102 of FIG. 3, the control state of the MCLAG port Pm2 of the switching device SW2 is changed from the transmission / reception permitted state FW to the transmission / reception prohibited state BK.

  For this reason, the relay processing unit 16 changes the destination port identifier DP to the port identifier {Pb} of the bridge port Pb. The relay processing unit 16 then returns the user frame UF12a to which the destination port identifier DP ({Pb}), the reception port identifier SP ({MCLAG1}), and the first identifier SP2 ({Pb}) are added, to the loopback prohibiting unit 17. Via the interface unit 20. At this time, the loopback prohibition unit 17 does not match the destination port identifier DP ({Pb}) and the reception port identifier SP ({MCLAG1}), but the destination port identifier DP ({Pb}) and the first identifier SP2. Since it matches ({Pb}), passage of the user frame UF12a is prohibited and the user frame UF12a is discarded.

  As described above, the first identifier adding unit 15 can be configured by applying, for example, a function (that is, the reception port identifier adding unit 22) that is normally provided in the switch device. Can be configured by applying a function (frame folding prohibiting function) that is normally provided. Thereby, it is possible to prevent the frame from being folded with a simple configuration and operation.

As described above, by using the relay system and the switch device according to the first embodiment, it is typically possible to prevent the frame from being folded back (second embodiment).
<< Configuration of Switch Device (Modification) >>
FIG. 8 is a schematic diagram showing a configuration example of the switch device according to the second embodiment of the present invention. The switch device SW shown in FIG. 8 differs from the configuration example of FIG. 4 described above in that the first identifier adding unit 15 is provided not in the reception port identifier adding unit 25 but in the frame processing unit 13. Yes. Further, as in the case of FIG. 3, the relay system including the switch device SW of FIG. 8 does not add the first identifier SP2 when the frame is received by the bridge port Pb, but uses the bridge port Pb. When transmitting a frame, an operation is performed to add the first identifier SP2.

<< Operation of Switch Device (Modification) >>
FIG. 9 is an explanatory diagram showing an example of the operation of the switch device of FIG. Similarly to the case of FIG. 6, the switching device SW1 receives the user frame UF12a including the source MAC address SA (here, MA1) and the destination MAC address DA (here, MA2) at the MCLAG port Pm1. The reception port identifier adding unit 25 adds the port identifier {Pm1} that is the reception port identifier SP to the user frame UF12a.

  The subsequent operations of the relay processing unit 16 and the turn-back prohibiting unit 17 are the same as in the case of FIG. In brief, the relay processing unit 16 learns the source MAC address MA1 in the address table FDB in association with the MCLAG identifier {MCLAG1}. Further, the relay processing unit 16 acquires the MCLAG identifier {MCLAG2} that is the destination port identifier DP by searching the address table FDB. However, since the member port of the MCLAG identifier {MCLAG2} is controlled to the transmission prohibited state TBK, the relay processing unit 16 changes the destination port identifier DP to the port identifier {Pb}.

  Further, the relay processing unit 16 changes the reception port identifier SP from the port identifier {Pm1} to the MCLAG identifier {MCLAG1}. Then, unlike the case of FIG. 6, the relay processing unit 16 adds the user frame UF12a to which the destination port identifier DP and the reception port identifier SP are added to the loopback prohibiting unit 17 and adds the first identifier provided at the subsequent stage. The data is transmitted to the interface unit 20 via the unit 15.

  At this time, the turn-back prohibition unit 17 permits the passage of the user frame UF12a to which the destination port identifier DP and the reception port identifier SP are added in the same manner as in FIG. Thereafter, unlike the case of FIG. 6, the first identifier adding unit 15 further adds a port identifier {Pb} that is a second reception port identifier (first identifier) SP2 to the frame permitted to pass. Append. In other words, by providing the first identifier adding unit 15 at the subsequent stage of the anti-folding unit 17, the anti-blocking unit 17 prevents the frame from being blocked. As in the case of FIG. 6, the interface unit 20 deletes the destination port identifier DP and converts the user frame UF12a to which the reception port identifier SP and the second reception port identifier (first identifier) SP2 are added into the bridge port. Send to Pb.

  On the other hand, although not shown, the switching device SW2 receives the user frame UF12a at the bridge port Pb. Here, the reception port identifier adding unit 25 of the switching device SW2 does not particularly add a reception port identifier. Therefore, the frame after passing through the receiving port identifier adding unit 25 is the same as the frame after passing through the first identifier adding unit 15 in FIG. 7, and the receiving port identifier SP and the second receiving port identifier (first identifier) SP2 Is added. Thereafter, similarly to the case of FIG. 7, processing by the relay processing unit 16 and the loopback prohibition unit 17 is performed, and the loopback prohibition unit 17 prevents relaying of the user frame UF12a.

  As described above, even when the relay system and the switch device according to the second embodiment are used, the same effect as in the first embodiment can be obtained. However, in the methods of FIGS. 8 and 9, there may be a case where a device for configuration is required such that the first identifier adding unit 15 is provided after the anti-folding unit 17. Furthermore, it is necessary to change the frame transmitted between the bridge ports Pb to a format different from the normal one. That is, the frame may be added with the second reception port identifier (first identifier) SP2 in addition to the reception port identifier SP. Therefore, from the viewpoint of simplification of the configuration and operation, it is desirable to use the methods of FIGS.

  As mentioned above, the invention made by the present inventor has been specifically described based on the embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention. For example, the above-described embodiment has been described in detail for easy understanding of the present invention, and is not necessarily limited to one having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. . Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

10 [1], 10 [2] Communication device 11, 12 Communication line 13 Frame processing unit 14 MCLAG table 15 First identifier addition unit 16 Relay processing unit 17 Loopback prohibition unit 20 Interface unit 21 Failure detection unit 22, 25 Reception port identifier Additional unit 23 Control frame processing unit 24 Port control unit ACT Active BK Transmission / reception prohibited state CPU processor unit DA Destination MAC address DP Destination port identifier FDB Address table FW Transmission / reception permission state MCLAGSW MCLAG switch Pb Bridge port Pm1, Pm2 MCLAG port Pu1, Pu2 port SA source MAC address SBY standby SP receiving port identifier SP2 second receiving port identifier (first identifier)
SW, SW1, SW2 Switch device TBK Transmission prohibited state UF12a, UF12b User frame VID VLAN identifier

Claims (12)

A first switch device having a plurality of ports each including a bridge port and a first MCLAG port in which a device-to-device LAG is set, and connected to each other via a communication line via the bridge port; A relay system comprising two switch devices,
Each of the first switch device and the second switch device is:
An MCLAG table that holds the first MCLAG port in association with a first MCLAG identifier;
An address table holding a correspondence relationship between a port identifier representing the port or an MCLAG identifier associated with the port and a MAC address existing ahead of the port;
When a frame is received at the first MCLAG port and the frame is relayed to the bridge port, the first MCLAG identifier is added to the frame and the first MCLAG identifier from the peer device is added. Is received at the bridge port, the transmission source MAC address of the frame is learned in the address table in association with the first MCLAG identifier added to the frame, and the frame is relayed to the destination port. And
A first identifier adding unit for adding a first identifier to the frame to which the first MCLAG identifier is added;
When the destination port of the frame to which the first identifier is added is the bridge port, a loopback prohibiting unit that prohibits relay of the frame;
Having
Relay system. The relay system according to claim 1,
The first identifier adding unit adds the first identifier to the frame when receiving the frame with the MCLAG identifier added to the bridge port;
Relay system. The relay system according to claim 1,
The first identifier adding unit adds the first identifier to the frame when transmitting the frame with the MCLAG identifier added to the bridge port.
Relay system. The relay system according to claim 1,
When the relay processing unit receives a frame from a peer device at the bridge port, the relay processing unit searches the address table and determines a destination port of the frame based on the search result.
Relay system. The relay system according to claim 1,
When the relay processing unit relays the frame to which the first MCLAG identifier is added to the bridge port, the relay processing unit further adds an identifier of a destination port based on the search result of the address table to the frame. When the frame to which the identifier of the destination port is added is received by the bridge port, the destination port of the frame is determined based on the identifier of the destination port.
Relay system. The relay system according to claim 1,
The plurality of ports further include a second MCLAG port in which a device-to-device LAG is set,
The MCLAG table further holds the second MCLAG port in association with a second MCLAG identifier,
The relay processing unit, when the destination of the frame received at the first MCLAG port of the own device is the second MCLAG identifier, and when the second MCLAG port of the own device and the peer device has no failure, Relay to one of the second MCLAG ports of the own device and peer device, and if the one second MCLAG port is faulty, relay the frame to the other second MCLAG port,
Relay system. A switch device having a plurality of ports including a bridge port and a first MCLAG port in which a device-to-device LAG is set, and connected to another switch device via the bridge port,
An MCLAG table that holds the first MCLAG port in association with a first MCLAG identifier;
An address table holding a correspondence relationship between a port identifier representing the port or an MCLAG identifier associated with the port and a MAC address existing ahead of the port;
When a frame is received at the first MCLAG port and the frame is relayed to the bridge port, the first MCLAG identifier is added to the frame, and the first MCLAG identifier from another switch device is added. When the received frame is received by the bridge port, the source MAC address of the frame is learned in the address table in association with the first MCLAG identifier added to the frame, and the frame is relayed to the destination port. A relay processing unit;
A first identifier adding unit for adding a first identifier to the frame to which the first MCLAG identifier is added;
When the destination port of the frame to which the first identifier is added is the bridge port, a loopback prohibiting unit that prohibits relay of the frame;
Having
Switch device. The switch device according to claim 7, wherein
The first identifier adding unit adds the first identifier to the frame when receiving the frame with the MCLAG identifier added to the bridge port;
Switch device. The switch device according to claim 7, wherein
The first identifier adding unit adds the first identifier to the frame when transmitting the frame with the MCLAG identifier added to the bridge port.
Switch device. The switch device according to claim 7, wherein
When the relay processing unit receives a frame from a peer device at the bridge port, the relay processing unit searches the address table and determines a destination port of the frame based on the search result.
Switch device. The switch device according to claim 7, wherein
When the relay processing unit relays the frame to which the first MCLAG identifier is added to the bridge port, the relay processing unit further adds an identifier of a destination port based on the search result of the address table to the frame. When the frame to which the identifier of the destination port is added is received by the bridge port, the destination port of the frame is determined based on the identifier of the destination port.
Switch device. The switch device according to claim 7, wherein
The plurality of ports further include a second MCLAG port in which a device-to-device LAG is set,
The MCLAG table further holds the second MCLAG port in association with a second MCLAG identifier,
The relay processing unit, when the destination of the frame received at the first MCLAG port of the own device is the second MCLAG identifier, and when the second MCLAG port of the own device and another switch device has no failure, Relay the frame to one of the second MCLAG ports of the own device and the other switch device, and relay the frame to the other second MCLAG port when the one second MCLAG port is faulty,
Switch device.

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