JP6591828B2 - Relay device and relay system - Google Patents

Description

  The present invention relates to a relay device and a relay system, for example, a relay device and a relay system to which LAG (Link Aggregation Group) is applied.

  For example, in Patent Document 1, in a communication system to which LAG based on LACP (Link Aggregation Control Protocol) is applied, by operating a synchronization bit or the like in a LAC PDU (LACP Data Unit), N + 1 consisting of a working link and a protection link. A scheme for realizing redundancy is shown.

JP 2008-160227 A

  For example, LACP defined in IEEE802.1AX and IEEE802.3ad is known as a protocol for setting LAG. When LACP is used, for example, a process of excluding a failed port from the LAG and a process of setting the LAG again to a port recovered from the failure can be automatically performed.

  However, for example, in the case of an unstable failure in which failure occurrence and failure recovery are repeated in a short time, there may occur a situation where the process of excluding a port from the LAG and the process of resetting the LAG for the port are frequently repeated. . In practice, a certain period of time is required after a failure occurs in a port until the port is excluded from the LAG. During this period, data communication cannot be performed normally (for example, a user frame is lost). Therefore, if the above-described processing is repeated, the abnormal period of data communication may be prolonged.

  The present invention has been made in view of the above, and an object of the present invention is to provide a relay device and a relay system that can shorten an abnormal period of data communication.

  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 apparatus according to the present embodiment includes a plurality of ports, a failure detection unit that detects a failure occurrence and a failure recovery for each of the plurality of ports, a LAG ( And a LAG control unit for setting a Link Aggregation Group. When a failure recovery is detected for a port excluded from the LAG in response to detection of a failure occurrence, the LAG control unit does not set a LAG for the port until an event based on a user instruction occurs.

  The effects obtained by the representative embodiments of the invention disclosed in the present application will be briefly described. In the relay device and the relay system, it is possible to shorten the abnormal period of data communication.

(A) And (b) is the schematic which shows the structural example and the operation example at the time of failure recovery in the relay system by one embodiment of this invention. FIG. 2 is a block diagram illustrating a schematic configuration example of a main part of a relay device in the relay system of FIGS. 1 (a) and 1 (b). (A) is a schematic diagram showing an example of the structure of the FDB in FIG. 2, (b) is a schematic diagram showing an example of the structure of the LAG relay table in FIG. 2, and (c) is a LAG management in FIG. It is the schematic which shows the structural example of a table. (A) is a state transition diagram showing an operation example of a recovery flag when the recovery flag is set to “not used” in the LAG management table of FIG. 3 (c), and (b) is a state transition diagram of FIG. FIG. 10 is a state transition diagram illustrating an operation example of a recovery flag when the recovery flag is set to use in the LAG management table of FIG. FIG. 3 is a flowchart showing an example of processing contents when a LAG control unit performs LAG setting in the relay device of FIG. 2. FIG. 6 is an explanatory diagram illustrating a specific operation example when a failure occurs in the LAG control unit of FIGS. FIG. 6 is an explanatory diagram illustrating a specific operation example at the time of failure recovery in the LAG control unit of FIGS. It is explanatory drawing which shows the operation example following FIG. (A), (b) and (c) are schematic diagrams showing a configuration example and an operation example when a failure occurs in the relay system studied as a premise of the present invention. (A) And (b) is the schematic which shows the operation example at the time of the failure recovery in the relay system of FIG.9 (c). (A) And (b) is the schematic which shows the format structural example of the principal part of a control frame (LACPDU).

  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.

<< Schematic configuration and outline of relay system (premise) >>
FIG. 9A, FIG. 9B, and FIG. 9C are schematic diagrams illustrating a configuration example and an operation example when a failure occurs in the relay system studied as a premise of the present invention. The relay system shown in FIG. 9A includes two relay devices 10a and 10b. Each of the relay devices 10a and 10b includes a plurality (here, three) of ports P1 to P3, a LAG control unit 11 ′, and a relay processing unit 12. The ports P1 to P3 of the relay device 10a are connected to the ports P1 to P3 of the relay device 10b via communication lines (for example, Ethernet (registered trademark) lines), respectively.

  The LAG control unit 11 'sets the LAG to a predetermined port among the ports P1 to P3 based on a predetermined protocol (here LACP). Here, based on LACP, the relay device 10a operates in the active mode, and the relay device 10b operates in the passive mode. The relay apparatus 10a (its LAG control unit 11 ') that operates in the active mode spontaneously transmits a control frame based on LACP (that is, LACPDU). On the other hand, when receiving a control frame, the relay device 10b (the LAG control unit 11 ') operating in the passive mode transmits the control frame in response to the control frame. The relay device 10b is not limited to the passive mode but may be in the active mode.

  In the example of FIG. 9A, the relay device 10a transmits control frames CF1ab, CF2ab, and CF3ab from the ports P1, P2, and P3, respectively, and the relay device 10b responds to these control frames in response to the ports P1, P2, and P3. Control frames CF1ba, CF2ba, and CF3ba are transmitted from P2 and P3, respectively. Here, in LACP, the LAG setting candidate ports, the maximum number of ports constituting the LAG, and the priority of each port can be set in advance. In the example of FIG. 9A, the LAG setting candidate ports are ports P1 to P3, the maximum number of ports is 2, and the priority of each port is ports P1, P2, and P3 in order of high priority.

  The LAG control unit 11 ′ of the relay device 10a selects a port with the maximum number of ports from the LAG setting candidate ports based on the priority of each port, and applies the LAG to the selected ports (here, P1 and P2). The process for setting is started. In the process, the LAG control unit 11 'transmits control frames (LACPDU) CF1ab and CF2ab whose synchronization bits and aggregation bits are both TRUE (' 1 ') from the selected ports P1 and P2. Further, the LAG control unit 11 ′ transmits a control frame CF 3 ab in which at least one of the synchronization bit and the aggregation bit is FALSE (“0”) from the non-selected port P 3 which is a LAG setting candidate port.

  When no failure has occurred, as shown in FIG. 9 (a), the LAG control unit 11 ′ of the relay apparatus 10b responds to the control frames CF1ab and CF2ab from the ports P1 and P2 in the same manner. Control frames (LACPDU) CF1ba and CF2ba whose aggregation bits are both “1” are transmitted. The LAG control unit 11 ′ of the relay apparatuses 10 a and 10 b sets LAG to the port that has transmitted and received the control frame in which both the synchronization bit and the aggregation bit are “1”.

  As a result, the LAG control unit 11 'of the relay devices 10a and 10b sets LAG (here, LAG1) to the ports P1 and P2. On the other hand, the LAG control unit 11 ′ does not set LAG in the port P3 that has transmitted or received the control frame in which at least one of the synchronization bit and the aggregation bit is “0”, and is superior to the ports P1 and P2. The port P3 having a low degree can be handled as a backup link when a failure occurs.

  When the destination port of the user frame UF received at a port (not shown) is LAG1, the relay processing unit 12 of the relay apparatuses 10a and 10b selects the frame from the ports P1 and P2 based on a predetermined distribution rule Relay to the specified port. Examples of the distribution rule include a method of performing a hash operation using the source MAC address and the destination MAC address of the user frame UF.

  FIG. 11A and FIG. 11B are schematic diagrams illustrating a format configuration example of a main part of a control frame (LACPDU). The control frame (LACPDU) CF includes header information 25, actor information 26, and partner information 27 as shown in FIG. The header information 25 includes a destination MAC address (DMAC), a source MAC address (SMAC), a type, and a subtype. A predetermined multicast address is stored in the destination MAC address, and eigenvalues (0x8809 and 0x01) representing LACPDU are stored in the type and subtype, respectively.

  The relay apparatus (for example, 10a) that transmits the control frame stores various information of the own apparatus in the actor information 26, and stores various information of the opposite apparatus (relay apparatus 10b) in the partner information 27. The partner information 27 is determined based on the actor information 26 of the control frame received from the opposite device. Each of the actor information 26 and the partner information 27 includes a key corresponding to an identifier of LAG (for example, LAG1), a port priority, a port identifier, and port states 28 and 29.

  As shown in FIG. 11B, each of the actor state 28 and the partner state 29 includes an aggregation bit 30 indicating whether or not link aggregation can be configured, and whether or not synchronization is possible (for example, a port is a key (LAG And a synchronization bit 31 indicating whether or not conditions for management and operation are met. When link aggregation can be configured, the aggregation bit 30 is TRUE ('1'), and when synchronization is possible, the synchronization bit 31 is TRUE ('1'). LAG is set to a port in which the aggregation bit 30 and the synchronization bit 31 in both states 28 and 29 are both TRUE ('1').

  In the relay system shown in FIG. 9B, unlike the case of FIG. 9A, a failure has occurred in the link of the port P1 (here, the communication line connected to the port P1). In this case, when the relay processing unit 12 of the relay apparatuses 10a and 10b distributes the user frame UF to the port P1 side, a loss may occur in the frame.

  In the relay system shown in FIG. 9C, unlike the case of FIG. 9B, the occurrence of a failure in the port P1 is detected (step S101), and the LAG1 setting is changed accordingly (step S102). ). Specifically, the LAG control unit 11 'of the relay device 10a starts the process for setting LAG1 to the port P3 that is the above-described backup link in response to the detection of the failure occurrence for the port P1.

  At this time, the LAG control unit 11 ′ transmits control frames (LACPDU) CF 2 ab and CF 3 ab in which both the synchronization bit 31 and the aggregation bit 30 are “1” from the ports P 2 and P 3. On the other hand, the LAG control unit 11 ′ excludes the port P 1 from the LAG 1 and transmits a control frame CF 1 ab in which at least one of the synchronization bit 31 and the aggregation bit 30 is “0” from the port P 1.

  The LAG control unit 11 ′ transmits such control frames CF2ab and CF3ab, and receives the control frames CF2ba and CF3ba in which both the synchronization bit 31 and the aggregation bit 30 are “1”, so that the port P2 , P3 is set to LAG1. Similarly, the LAG control unit 11 ′ of the relay device 10b also transmits and receives control frames in which the synchronization bit 31 and the aggregation bit 30 are both “1” at the ports P2 and P3, so that the ports P2 and P3 Set LAG1. As a result, the relay processing unit 12 of the relay apparatuses 10a and 10b distributes and relays the received user frame UF to the ports P2 and P3.

  FIG. 10A and FIG. 10B are schematic diagrams showing an operation example at the time of failure recovery in the relay system of FIG. 9C. In the relay system shown in FIG. 10A, unlike the case of FIG. 9C, the link failure of the port P1 is recovered. Similarly to the case of FIG. 9C, LAG1 is still set to the ports P2 and P3, and there is no particular loss of the user frame UF.

  In the relay system shown in FIG. 10B, unlike the case of FIG. 10A, the failure recovery of the port P1 is detected (step S201), and the setting change of LAG1 is performed accordingly (step S202). ). Specifically, the LAG control unit 11 'of the relay device 10a starts a process for setting LAG1 again to the port P1 having a higher priority than the port P3 in response to detection of failure recovery for the port P1.

  At this time, the LAG control unit 11 ′ transmits control frames (LACPDU) CF 1 ab and CF 2 ab in which both the synchronization bit 31 and the aggregation bit 30 are “1” from the ports P 1 and P 2. On the other hand, the LAG control unit 11 ′ excludes the port P 3 from LAG 1 and transmits a control frame CF 3 ab in which at least one of the synchronization bit 31 and the aggregation bit 30 is “0” from the port P 3.

  The LAG control unit 11 ′ transmits such control frames CF1ab and CF2ab, and receives the control frames CF1ba and CF2ba in which both the synchronization bit 31 and the aggregation bit 30 are “1”. , P2 is set to LAG1. Similarly, the LAG control unit 11 ′ of the relay apparatus 10b also transmits and receives a control frame in which both the synchronization bit 31 and the aggregation bit 30 are “1” at the ports P1 and P2, to the ports P1 and P2. Set LAG1. As a result, the relay processing unit 12 of the relay apparatuses 10a and 10b distributes and relays the received user frame UF to the ports P1 and P2.

<< Problems of relay system (premise) >>
Here, for example, a case is assumed where the link failure of the port P1 shown in FIG. 9B is an unstable failure in which failure occurrence and failure recovery are repeated in a short time. In this case, the state is switched to a loop in the order of FIG. 9 (b) → FIG. 9 (c) → FIG. 10 (a) → FIG. 10 (b) → FIG. 9 (b) →.

  In addition, it may take a certain period of time to switch from the state of FIG. 9B to the state of FIG. 9C. In particular, based on LACP, when at least one of the relay apparatuses 10a and 10b detects the occurrence of a failure by not receiving the control frame (LACPDU) CF, and the periodic transmission interval of the control frame is set to 30 seconds, The LAG control unit 11 ′ may not be able to detect a failure occurrence in a period three times (90 seconds) of the transmission interval. As shown in FIG. 9B, the period during which failure occurrence cannot be detected is a period during which loss of the user frame UF can occur, and is an abnormal period of data communication. Therefore, when an unstable failure occurs, an abnormal period of data communication occurs frequently, and the abnormal period of data communication may be prolonged as a whole.

<< Schematic configuration and schematic operation of relay system (this embodiment) >>
FIG. 1A and FIG. 1B are schematic diagrams illustrating a configuration example and an operation example at the time of failure recovery in a relay system according to an embodiment of the present invention. The relay system shown in FIG. 1A is different from the relay system shown in FIG. 10B in that a LAG control unit 11 having a different processing content from the LAG control unit 11 ′ is provided in the relay device 10a. Yes. Similarly to the case of FIG. 10B and the like, the LAG control unit 11 of the relay device 10a sets the LAG to a predetermined port among the plurality of ports P1 to P3 based on a predetermined protocol (here LACP).

  However, unlike the case of FIG. 10B, the LAG control unit 11 generates an event based on a user instruction when failure recovery is detected for a port excluded from the LAG in response to detection of the failure occurrence. Do not set LAG to the port until In the example of FIG. 1A, the LAG control unit 11 detects the link failure recovery of the port P1 (step S201), but unlike the case of FIG. The setting of LAG1 is maintained as it is (step S201a). During this period, the LAG control unit 11 controls the control frame in which at least one of the synchronization bit 31 or the aggregation bit 30 is “0” from the port P1 excluded from LAG1, as in the case of FIG. LACPDU) CF1ab is transmitted.

  Thereafter, in FIG. 1B, an event based on a user instruction has occurred (step S201b). The event is, for example, a command input by a user or an output of a timer. The timer measures the time instructed by the user after failure recovery is detected. The LAG control unit 11 starts changing the setting of LAG1 when failure recovery is detected and an event based on a user instruction occurs (step S202).

  That is, the LAG control unit 11 controls the control frames (LACPDU) CF1ab and CF2ab from the ports P1 and P2 in which both the synchronization bit 31 and the aggregation bit 30 are “1” as in the case of FIG. Send. On the other hand, the LAG control unit 11 excludes the port P3 from the LAG1, and transmits a control frame CF3ab from the port P3 in which at least one of the synchronization bit 31 and the aggregation bit 30 is “0”.

  The LAG control unit 11 transmits such control frames CF1ab and CF2ab, and similarly receives the control frames CF1ba and CF2ba in which both the synchronization bit 31 and the aggregation bit 30 are “1”, so that the ports P1, LAG1 is set to P2. Similarly, the LAG control unit 11 ′ of the relay apparatus 10b also transmits and receives a control frame in which both the synchronization bit 31 and the aggregation bit 30 are “1” at the ports P1 and P2, to the ports P1 and P2. Set LAG1.

  Thereby, typically, it is possible to shorten the abnormal period of data communication. Specifically, for example, when failure recovery is detected as shown in FIG. 1A (step S201), the user can confirm that the failure recovery of the port P1 is not temporary and can confirm it. At this stage, an event as shown in FIG. 1B may be generated (step S201b). As a result, as described above, the situation in which the state of FIG. 9B occurs frequently can be prevented, and the period during which the loss of the user frame UF can occur can be shortened.

<< Schematic configuration and operation of relay device >>
FIG. 2 is a block diagram illustrating a schematic configuration example of a main part of the relay device in the relay system of FIGS. 1 (a) and 1 (b). 2 includes a plurality of ports P1, P2, P3,..., Pn, an interface unit 15, a relay processing unit 12, an FDB (Forwarding DataBase). ), The LAG control unit 11, the LAG relay table 16, the LAG management table 17, and the device management unit 18. Here, the relay device 10 is a layer 2 (L2) switch as an example, but may be a layer 3 (L3) switch or a switch having a higher layer processing function, for example.

  Each of the plurality of ports P1 to Pn transmits or receives a frame. The interface unit 15 includes a frame identification unit 19, a reception port identifier addition unit 20, and a failure monitoring unit 21. When a frame is received at a predetermined port, the reception port identifier adding unit 20 adds the received port identifier (referred to as a reception port identifier) to the frame.

  The frame identifying unit 19 identifies various frames, for example, whether a frame received at a predetermined port is a user frame UF or a control frame (for example, a LACPDU) CF. This identification is performed, for example, by determining values such as type and subtype in the header information 25 in FIG. The frame identification unit 19 transmits the frame to the relay processing unit 12 when the received frame is the user frame UF, and transmits the frame to the LAG control unit 11 when the received frame is the control frame (LACPDU) CF. . A reception port identifier is added to the frame transmitted to the relay processing unit 12 and the LAG control unit 11.

  The failure monitoring unit 21 detects the presence or absence of a failure (link up / link down) for each of a plurality of ports by hardware. For example, the failure monitoring unit 21 monitors the received optical signal level, and determines that the link is down when an abnormal state such as an insufficient optical signal level continues for a predetermined period. Alternatively, the failure monitoring unit 21 monitors the presence / absence of the link pulse signal generated in the idle state and the presence / absence of the data signal in the non-idle state from the received signal, and the abnormal state such that both the link pulse signal and the data signal are absent. Is determined to be link-down when it continues for a predetermined period.

  The LAG control unit 11 includes a control frame processing unit 23 that transmits or receives a control frame (for example, LACPDU) CF. Based on a predetermined protocol (for example, LACP), the LAG control unit 11 transmits a LAG to a predetermined port among the plurality of ports P1 to Pn. Set. At this time, the LAG control unit 11 sets the LAG based on the LAG management table 17 and stores the setting contents of the LAG (that is, to which port the LAG is set) in the LAG relay table 16 as will be described in detail later. To do.

  The control frame processing unit 23 periodically transmits or receives a control frame (LACPDU) CF at a predetermined port based on a predetermined interval (for example, every 1 second or every 30 seconds). At this time, the control frame processing unit 23 is unable to receive the control frame CF at a predetermined port for a predetermined period (for example, a period of three times a predetermined interval), or when the control frame processing unit 23 receives the synchronization bit 31 and the aggregation of the received control frame CF. When both of the control bits 30 are not “1”, the occurrence of a failure in the port is detected. As described above, the control frame processing unit 23 functions as a failure detection unit that detects the occurrence of failure and recovery from failure of each of the plurality of ports P1 to Pn together with the failure monitoring unit 21 described above.

  3A is a schematic diagram illustrating an example of the structure of the FDB in FIG. 2, FIG. 3B is a schematic diagram illustrating an example of the structure of the LAG relay table in FIG. 2, and FIG. FIG. 3 is a schematic diagram showing a structural example of a LAG management table in FIG. 2. As shown in FIG. 3A, the FDB holds a correspondence relationship between a MAC address, a VLAN (Virtual Local Area Network) identifier (VID), and a port identifier / LAG identifier.

  In the example of FIG. 3A, for example, a terminal or the like having the MAC address MA1 and VID “xxx” exists ahead of LAG1 (ports P1 and P2 in the example of FIG. 2), and the MAC address MA3 and VID “ A terminal having “xxx” exists at the end of the port Pn. In FIG. 3A, for example, {LAG1} represents an identifier (ID) of LAG1, and in the same manner, in the present specification, for example, {AA} represents an identifier of “AA”.

  As shown in FIG. 3C, the LAG management table 17 includes a LAGID, a maximum number of ports for setting the LAGID, a port ID representing a port that is a candidate for setting the LAGID, and various information for each port ID. Hold. The various information includes a priority, a setting bit for determining whether or not to use a recovery flag (details will be described later), a recovery flag for determining recovery OK / NG, and whether or not a link status and control frame (CF) are received. And a failure state consisting of

  In the example of FIG. 3C, the maximum number of ports of LAG1 is 2, and ports P1, P2, and P3 are LAG1 setting candidate ports. The ports P1, P2, and P3 are set to have higher dominance in the order of the ports P1, P2, and P3, and the recovery flags are both set to use, and both are in a state of no failure. The failure-free state means that a link up is detected by the failure monitoring unit 21 and a control frame in which both the synchronization bit 31 and the aggregation bit 30 are “1” is received within a predetermined period by the control frame processing unit 23. It is a state that has been. Here, a case where one LAG is set in the relay apparatus 10 is taken as an example, but it is of course possible to set a plurality of LAGs.

  In the LAG management table 17, the LAGID, the maximum number of ports, the port ID, the priority, and the setting bit (whether or not the recovery flag is used) are set in advance by the user. Although not particularly limited, for example, the user performs various settings while communicating with the device management unit 18 of the relay device 10 using a management terminal or the like, and the device management unit 18 performs LAG management via the LAG control unit 11. The setting information is stored in the table 17. The device management unit 18 manages settings, states, and the like of the entire relay device 10 including such communication with the outside of the device.

  As shown in FIG. 3 (b), the LAG relay table 16 includes a LAGID, a port ID representing a setting candidate port of the LAGID, and a valid / invalid bit representing which of the port IDs is valid / invalid. And hold. The LAG control unit 11 determines the LAGID and port ID of the LAG relay table 16 based on the LAG management table 17. Further, the LAG control unit 11 selects a predetermined port based on a predetermined protocol (for example, LACP) from the LAGID setting candidate ports while referring to the LAG management table 17, and the LAG relay table 16 selects the selected port. Set the valid ports. In the example of FIG. 3B, the ports P1 and P2 are set to be valid, and as a result, LAG1 is set to the ports P1 and P2.

  In FIG. 2, the relay processing unit 12 includes a LAG distribution unit 22 and performs FDB learning and search when a frame is received. For example, it is assumed that a frame including the source MAC address “MA3” and the destination MAC address “MA1” is received at the port Pn. In this case, for example, the relay processing unit 12 learns the transmission source MAC address “MA3” (and its VID) in the FDB in association with the reception port identifier {Pn} added to the frame. Also, the relay processing unit 12 searches the FDB using the destination MAC address “MA1” (and its VID) as a search key, and acquires the identifier of the port that is the destination of the frame (referred to as the destination port identifier) {LAG1}. .

  When the destination port identifier is LAGID (in this case, {LAG1}), the LAG distribution unit 22 refers to the LAG relay table 16 and selects one of the ports (in this case, P1 and P2) in which LAG1 is set. Select the port. At this time, although not particularly limited, the LAG distribution unit 22 selects one of the ports by performing a hash operation using the transmission source MAC address and the destination MAC address.

  The LAG distribution unit 22 determines the port identifier (for example, {P1}) of the selected port as the destination port identifier, and transmits the frame with the destination port identifier added thereto to the interface unit 15. The interface unit 15 relays the frame to the port (P1) indicated by the destination port identifier. For example, when receiving a frame at a port (for example, P2) where LAG1 is set, the relay processing unit 12 acquires the LAGID based on the LAG relay table 16, and sets the transmission source MAC address of the frame. The FDB learns in association with the LAGID.

  Here, although not necessarily limited, the interface unit 15 and the relay processing unit 12 in FIG. 2 are configured by using one or a plurality of ASIC (Application Specific Integrated Circuit) or FPGA (Field Programmable Gate Array). The FDB is configured by a CAM (Content Addressable Memory) or the like. The LAG control unit 11 and the device management unit 18 are configured by program processing using a CPU (Central Processing Unit). The LAG relay table 16 and the LAG management table 17 are composed of a RAM (Random Access Memory) or the like. The LAG relay table 16 may be composed of a RAM or the like in the same chip as the relay processing unit 12.

<Details of recovery flag>
FIG. 4A is a state transition diagram showing an operation example of the recovery flag when the recovery flag is set to “not used” in the LAG management table of FIG. 3C, and FIG. FIG. 3C is a state transition diagram illustrating an operation example of a recovery flag when the recovery flag is set to use in the LAG management table of 3 (c). The state transitions in FIGS. 4A and 4B are controlled by the LAG control unit 11 in FIG.

  In FIG. 4A, the recovery flag in the LAG management table 17 takes two states of OK / NG. The LAG control unit 11 changes the recovery flag to NG regardless of the current state according to the detection of the occurrence of the failure, and changes the recovery flag to OK regardless of the current state according to the detection of the failure recovery. In the LAG setting candidate port, the occurrence of a failure is detected when the ring monitoring is detected by the failure monitoring unit 21 as described above or when the control frame cannot be normally received by the control frame processing unit 23. . Failure recovery is detected when a ringup is detected by the failure monitoring unit 21 or when a control frame can be normally received by the control frame processing unit 23.

  On the other hand, in FIG. 4B, the recovery flag takes three states of Wait in addition to OK / NG. As in the case of FIG. 4A, the LAG control unit 11 changes the recovery flag to NG regardless of the current state in response to the detection of the failure occurrence. On the other hand, unlike the case of FIG. 4A, the LAG control unit 11 temporarily changes the recovery flag to Wait in response to detection of failure recovery when the recovery flag is NG, and an event is generated in that state. In response to this, the recovery flag is shifted to OK.

<< LAG control unit LAG setting process >>
FIG. 5 is a flowchart showing an example of processing contents when the LAG control unit performs LAG setting in the relay apparatus of FIG. In FIG. 5, the LAG control unit 11 determines whether or not the recovery flag has changed to OK / NG (that is, change from another state to OK or change from another state to NG) in the LAG management table 17. Is monitored (step S301). When a change to OK / NG occurs, the LAG control unit 11 is a LAG setting candidate port (for example, ports P1 to P3), and the maximum number of ports is selected based on the priority from the ports whose recovery flag is OK. (For example, two ports) are selected (step S302).

  Next, the LAG control unit 11 (specifically, the control frame processing unit 23) transmits a control frame (LACPDU) CF in which both the synchronization bit 31 and the aggregation bit 30 are “1” from the selected port (step) S303). In parallel with this, the control frame processing unit 23 selects a control frame CF in which at least one of the synchronization bit 31 and the aggregation bit 30 is “0” from a non-selected port, which is a LAG setting candidate port. Transmit (step S303).

  Subsequently, the LAG control unit 11 sets LAG to the port that has transmitted and received the control frame (LACPDU) CF in which both the synchronization bit 31 and the aggregation bit 30 are “1” (step S304). That is, the LAG control unit 11 effectively determines the port in which this LAG is set in the LAG relay table 16.

  Thereafter, the LAG control unit 11 (specifically, the control frame processing unit 23), based on the LAG relay table 16, controls frames (LACPDU) in which both the synchronization bit 31 and the aggregation bit 30 are “1” from the valid port. ) CF is transmitted (step S305). In parallel with this, the control frame processing unit 23, based on the LAG relay table 16, starts synchronization bits 31 and aggregation from an invalid port (that is, a port for which LAG is set but LAG is not set). A control frame CF in which at least one of the bits 30 is “0” is transmitted (step S305). In step S301, the LAG control unit 11 executes the processing in step S305 even when there is no change in the recovery flag.

  FIG. 6 is an explanatory diagram illustrating a specific operation example when a failure occurs in the LAG control unit of FIGS. FIG. 7 is an explanatory diagram illustrating a specific operation example at the time of failure recovery in the LAG control unit illustrated in FIGS. 2 to 5, and FIG. 8 is an explanatory diagram illustrating an operation example subsequent to FIG. 7. Here, a case where the recovery flag is set to use is taken as an example.

  In FIG. 6, a failure has occurred in the link of the port P1 of the relay apparatus 10a. The LAG control unit 11 of the relay device 10a detects the failure by the failure monitoring unit 21 and / or the control frame processing unit 23 serving as a failure detection unit (step S101). Here, it is assumed that both the failure monitoring unit 21 and the control frame processing unit 23 have detected a failure. In response to this, the LAG control unit 11 sets the link state of the port P1 to link down, sets whether the control frame CF is received or not in the LAG management table 17, receives the detection of the failure, and receives the detection of the failure. As shown in (b), the recovery flag is changed to NG (step S101a).

  Next, since the recovery flag has transitioned to NG, the LAG control unit 11 determines the maximum number of ports (here, 2) based on the priority among the ports whose recovery flag is OK based on step S302 in FIG. Then, the ports P2 and P3) are selected. Thereafter, the LAG control unit 11 sets LAG1 to the ports P2 and P3 through the processing of steps S303 and S304 in FIG. That is, the LAG control unit 11 invalidates the port P1 and validates the ports P2 and P3 in the LAG relay table 16 (step S102).

  In FIG. 7, the failure of the link of the port P1 of the relay device 10a has been recovered. The LAG control unit 11 of the relay apparatus 10a detects the failure recovery by the failure monitoring unit 21 and / or the control frame processing unit 23 (step S201). Here, it is assumed that the failure monitoring unit 21 detects failure recovery. In response to this, the LAG control unit 11 sets the link state of the port P1 to link up in the LAG management table 17, receives the detection of the failure recovery, and as shown in FIG. Is shifted to Wait (step S201a).

  In FIG. 8, an event based on a user instruction has occurred with the recovery flag set to Wait (step S201b). As described above, the event is a command input by a user, a timer output, or the like. In the former case, as a premise, for example, the device management unit 18 in FIG. 2 notifies the user (user terminal or the like) when the LAG control unit 11 detects occurrence of a failure or detects failure recovery. When the user receives a failure recovery detection notification, for example, immediately after that, the user confirms that the failure occurrence detection notification is not received (that is, is not an unstable failure). A command is input to 18. The device management unit 18 notifies the LAG control unit 11 that the command input has been performed.

  On the other hand, in the latter case, as a premise, for example, the LAG control unit 11 includes a timer. The timer outputs a predetermined signal after measuring the time instructed by the user via the device management unit 18 in advance using the transition of the recovery flag to Wait as a trigger. The LAG control unit 11 transitions the recovery flag in the LAG management table 17 to OK when receiving a command input notification from the device management unit 18 as described above or when receiving a timer output ( Step S202a).

  Next, since the recovery flag has transitioned to OK, the LAG control unit 11 determines the maximum number of ports (here, 2) based on the priority from the ports whose recovery flag is OK based on step S302 in FIG. Then, the ports P1 and P2) are selected. Thereafter, the LAG control unit 11 starts processing for setting LAG1 to the ports P1 and P2 in step S303 of FIG. In the process, whether or not the control frame CF is received in the LAG management table 17 is received (step S202b). And the said LAG control part 11 sets LAG1 to port P1, P2 through the process of step S304 of FIG. That is, the LAG control unit 11 invalidates the port P3 and validates the ports P1 and P2 in the LAG relay table 16 (step S203).

  As described above, the LAG control unit 11 does not set a LAG for a predetermined port until at least the recovery flag is OK (step S302). As shown in FIG. 4B, the recovery flag is OK according to the detection of failure recovery and the occurrence of an event. By providing such a recovery flag, the operations as shown in FIGS. 1A and 1B can be easily realized.

  Here, as shown in FIG. 3C, a setting bit for determining whether or not the recovery flag is used is provided. For example, when the recovery flag is set to “not used”, the same operation as in FIGS. 10A and 10B is performed at the time of failure recovery. That is, when detecting the failure recovery, the LAG control unit 11 shifts the failure recovery flag to OK based on FIG. 4A, and in response to this, the predetermined port (for example, P1, P2) is changed based on FIG. The process for setting LAG1 is immediately started (step S302 in FIG. 5).

  For example, when the user can tolerate frame loss to some extent, the LAG or port detects failure recovery instead of the recovery method as shown in FIG. 1 (a) and FIG. 1 (b). Then, there are cases where it is desired to apply a recovery method as shown in FIGS. Further, for example, in FIG. 9A and the like, there is a case where a recovery method as shown in FIG. 1A and FIG. Therefore, it is useful to provide a setting bit that determines whether or not the recovery flag is used. The setting bits are provided in units of ports in the example of FIG. 3C or the like, but can be provided in units of LAGs.

  Further, in the present embodiment, since the process of FIG. 5 is commonly used regardless of whether or not the recovery flag is used, as shown in FIG. 4A, even when the recovery flag is not used, the original function ( In other words, the restoration flag is used for the sake of convenience with a function different from that shown in FIG. However, when the recovery flag is not used, the LAG control unit 11 may be configured not to use the recovery flag at all because the LAG control unit 11 may simply perform a general operation.

  As mentioned above, although the invention made by the present inventor has been specifically described based on the embodiments, 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 embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those 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.

  For example, although the case where LACP is used as a protocol for LAG has been described as an example, the present invention is not necessarily limited to LACP, and can be similarly applied to other protocols. In addition, here, a configuration example and an operation example in which a spare link is provided are shown, but the present invention can be similarly applied to a configuration in which a spare link is not provided. That is, for example, in FIG. 9B, when the port P3 is not provided, the degenerate operation at the port P2 is performed, and when the failure of the port P1 is recovered, the LAG is set to the port P1 again. In this case, the method of this embodiment can be applied.

10, 10a, 10b Relay device 11, 11 ′ LAG control unit 12 Relay processing unit 15 Interface unit 16 LAG relay table 17 LAG management table 18 Device management unit 19 Frame identification unit 20 Receive port identifier addition unit 21 Fault monitoring unit 22 LAG distribution Unit 23 Control frame processing unit 25 Header information 26 Actor information 27 Partner information 28, 29 State 30 Aggregation bit 31 Synchronization bit CF, CF1ab to CF3ab, CF1ba to CF3ba Control frame P1 to Pn Port UF User frame

Claims (4)

Multiple ports,
A failure detection unit for detecting a failure occurrence and a failure recovery for each of the plurality of ports;
A LAG controller configured to set a LAG (Link Aggregation Group) to a predetermined port among the plurality of ports based on LACP (Link Aggregation Control Protocol) ;
A relay device having
The LAG control unit has a recovery flag that determines OK / NG for recovery, and when the failure recovery is detected for a port excluded from LAG in response to the detection of the failure occurrence, the recovery flag is OK. without setting the LAG to the port until,
The recovery flag becomes NG in response to the detection of the failure occurrence, and becomes OK in response to the detection of the failure recovery and the occurrence of a command input by the user,
The LAG control unit
A LACPDU (LACP Data Unit) in which at least one of a synchronization bit or an aggregation bit of a state is “0” from a port excluded from the LAG in a period from detection of the failure recovery to generation of the command. Send
After the command input occurs, send a LACPDU in which both the synchronization bit and the aggregation bit are '1'.
Relay device. The relay device according to claim 1 ,
The LAG control unit further includes a setting bit that allows a user to set whether or not the recovery flag is used. When the recovery flag is set to no use, the failure recovery can be performed for a port excluded from the LAG. If detected, immediately start processing to set LAG for the port,
Relay device. A relay system having two relay devices connected to each other via a plurality of communication lines,
One of the two relay devices is
A plurality of ports respectively connected to the plurality of communication lines;
A failure detection unit for detecting a failure occurrence and a failure recovery for each of the plurality of ports;
A LAG controller configured to set a LAG (Link Aggregation Group) to a predetermined port among the plurality of ports based on LACP (Link Aggregation Control Protocol) ;
Have
The LAG control unit has a recovery flag that determines OK / NG for recovery, and when the failure recovery is detected for a port excluded from LAG in response to the detection of the failure occurrence, the recovery flag is OK. without setting the LAG to the port until,
The recovery flag becomes NG in response to the detection of the failure occurrence, and becomes OK in response to the detection of the failure recovery and the occurrence of a command input by the user,
The LAG control unit
A LACPDU (LACP Data Unit) in which at least one of a synchronization bit or an aggregation bit of a state is “0” from a port excluded from the LAG in a period from detection of the failure recovery to generation of the command. Send
After the command input occurs, send a LACPDU in which both the synchronization bit and the aggregation bit are '1'.
Relay system. The relay system according to claim 3 ,
The LAG control unit further includes a setting bit that allows a user to set whether or not the recovery flag is used. When the recovery flag is set to no use, the failure recovery can be performed for a port excluded from the LAG. If detected, immediately start processing to set LAG for the port,
Relay system.

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