Communication device and control device

Abstract

A control device (20) that sets a plurality of time slots for each of a plurality of ports of a communication device in which a link aggregation group is set, the link aggregation group bundling and treating the plurality of ports as one port set, comprises: a storage unit (22) that stores a first gate control list for each of the plurality of ports; and a control unit (21) that, upon receiving failure information indicating at least one port in which a failure has occurred, identifies, on the basis of the failure information, a prescribed port other than the at least one port , creates a second gate control list that opens time slots for ports other than the prescribed port, and transmits the first gate control list and the second gate control list to the communication device.

Description

Communication device and control device

[0001] The present disclosure relates to a communication device and a control device.

[0002] In Non-Patent Document 1, TAS is defined. "TAS" is an abbreviation for time aware shaper. In Non-Patent Document 2, LAG is defined. "LAG" is an abbreviation for link aggregation group. LAG is a technique for redundantizing ports by regarding a plurality of physical ports as a virtual single port.

[0003] IEEE Computer Society, IEEE Std 802.1Qbv-2015, IEEE Standard for Local and metropolitan area networks -- Bridges and Bridged Networks - Amendment 25: Enhancements for Scheduled Traffic, 2016-03-18LAN MAN STANDARDS COMMITTEE, et al. Amendment to Carrier Sense Multiple Access with Collision Detection (CSMA / CD) Access Method and Physical Layer Specifications-Aggregation of Multiple Link Segments, IEEE Std, 802 3ad, 2000

[0004] By constructing a network with a plurality of nodes having a TAS function, a network function for guaranteeing the maximum delay and the maximum jitter, that is, delay-guaranteed communication can be realized. At this time, it is necessary to allocate a time slot dedicated to delay-guaranteed communication to the output ports of all nodes passing through end-to-end.

[0005] The mechanism of TAS is shown in Figure 7. TAS performs priority control by determining which traffic to transmit according to a time-division schedule. Specifically, TAS stores frames in a FIFO queue for each VLAN-CoS or IP-ToS and allows transmission from queues whose gates are open according to the GCL. "VLAN" is an abbreviation for virtual local area network. "CoS" is an abbreviation for class of service. "IP" is an abbreviation for Internet Protocol. "ToS" is an abbreviation for type of service. "FIFO" is an abbreviation for first in, first out. "GCL" is an abbreviation for gate control list.

[0006] An example of a GCL is shown in Figure 8. The TAS can control best-effort traffic and delay-guaranteed traffic in a superimposed manner. In the example shown in Figure 8, four ST flows and one NST flow are multiplexed. "ST" is an abbreviation for scheduled traffic. "NST" is an abbreviation for non-scheduled traffic. ST flows correspond to delay-guaranteed traffic. NST flows correspond to traffic that is not delay-guaranteed, i.e., best-effort traffic. The GCL shown in Figure 8 specifies that ST with CoS "7" is permitted in time slots 1 and 3, ST with CoS "5" in time slot 2, ST with CoS "4" in time slot 4, and NST with CoS "3" or less in time slot 5. This GCL further specifies that the length of time for which communication is permitted in each time slot from time slot 1 to time slot 4 is 15 microseconds, and the length of time for which communication is permitted in time slot 5 is 100 microseconds.

[0007] To avoid collisions end-to-end, all nodes in the network must be time-synchronized, and the opening and closing timing of the GCL gates at each node must be synchronized. The GCL is either centrally managed by a controller called a CNC, or managed individually at each node. "CNC" is an abbreviation for centralized network configuration. Each node opens its gate considering propagation delay, thus preventing collisions with other communications and enabling communication without queuing delays. The transmitting terminal is also time-synchronized and periodically transmits frames in accordance with the GCL timing, enabling communication without queuing delays.

[0008] It is conceivable to apply TAS to a communication device in which LAG is configured. Multiple physical ports of the communication device are aggregated and treated as a single logical port. In other words, multiple physical ports constitute LAG. If some of the multiple ports that make up LAG fail, it is necessary to reconfigure the GCL for the communication device, but reconfiguring it each time is time-consuming.

[0009] In light of these circumstances, the purpose of this disclosure is to apply TAS to a communication device in which LAG is configured, and to improve the efficiency of GCL reconfiguration when some of the multiple ports constituting LAG fail.

[0010] A control device according to one embodiment is a control device that sets a plurality of time slots for each of the plurality of ports of a communication device in which a link aggregation group is set to treat a plurality of ports as a single port, and comprises: a communication unit that communicates with the communication device; a storage unit that stores a first gate control list for each of the plurality of ports which defines the plurality of time slots and a flow with a fixed transmission period to be passed through each time slot; and a control unit which, when fault information indicating at least one port among the plurality of ports that has failed is received from the communication device via the communication unit, identifies a port other than the at least one port as a predetermined port based on the fault information, selects and reads the first gate control list for the predetermined port from the storage unit, creates a second gate control list which defines that the plurality of time slots should be opened for the ports other than the predetermined port, and transmits the read first gate control list and the created second gate control list to the communication device via the communication unit.

[0011] A communication device according to one embodiment is a communication device in which a link aggregation group is set up to treat a plurality of ports as a single port, and includes a storage unit, a first gate control list which defines a plurality of time slots and a flow with a fixed transmission period to be passed through each time slot for a predetermined port among the plurality of ports, and a second gate control list which defines opening the plurality of time slots for ports other than the predetermined port, and a control unit which refers to the first gate control list and the second gate control list to send the flow from the corresponding port.

[0012] According to this disclosure, by applying TAS to a communication device in which LAG is configured, it is possible to streamline the reconfiguration of GCL when some of the multiple ports constituting LAG fail.

[0013] This is a diagram showing the system configuration. This is a block diagram showing the control device configuration. This is a block diagram showing the communication device configuration. This is a flowchart showing the system operation. This is a diagram showing the first GCL set. This is a diagram showing the update GCL set. This is a diagram showing the mechanism of the TAS. This is a table showing examples of GCLs.

[0014] One embodiment will be described below with reference to the figures.

[0015] In each figure, identical or corresponding parts are denoted by the same reference numerals. In the description of this embodiment, the description of identical or corresponding parts will be omitted or simplified as appropriate.

[0016] Referring to Figure 1, the configuration of the system 10 according to this embodiment will be described.

[0017] System 10 comprises a control device 20 and a plurality of communication devices 30. The plurality of communication devices 30 include a communication device 30L configured with LAG settings that bundle multiple ports together and treat them as a single port. The control device 20 and each communication device 30 are connected by a control communication network and can communicate with each other via the control communication network. The plurality of communication devices 30 form a communication network 11, which is a main signal communication network, and can transfer frames between any user terminals via the communication network 11.

[0018] The control device 20 is a computer that monitors and controls each communication device 30. Each communication device 30 is a device that accommodates users and forwards frames to a port designated for each destination user terminal. In this embodiment, the control device 20 functions as a CNC, and each communication device 30 functions as a TAS-compatible switch. Each communication device 30 performs TAS communication according to the GCL for each port. TAS communication refers to communication that uses TAS functionality to guarantee maximum delay and maximum jitter.

[0019] Communication device 30L can communicate with other communication devices 30L via multiple ports that are treated as a single port by LAG. Communication device 30L may also communicate with control device 20, communication devices 30 that are not configured with LAG, or user terminals via ports other than the multiple ports, or via some of the multiple ports.

[0020] Each user terminal can be, for example, a mobile device, a PC, or a server such as a cloud server. "PC" is an abbreviation for personal computer. Each user terminal can be either the start or end point of a flow.

[0021] The outline of this embodiment will now be described. The control device 20 sets multiple time slots for each of the multiple ports of the communication device 30L, which is configured with LAG, a grouping of multiple ports that is treated as a single port. The control device 20 stores a first GCL for each of the multiple ports, which defines the multiple time slots and a flow with a fixed transmission period that is to pass through each time slot. When the control device 20 receives fault information from the communication device 30L indicating at least one port among the multiple ports that has experienced a failure (hereinafter also referred to as the faulty port), it identifies the ports other than the faulty port as predetermined ports based on the fault information and selects and reads a first gate control list for the predetermined ports. For the ports other than the predetermined ports, the control device 20 creates a second gate control list which defines that multiple time slots should be opened. The control device 20 transmits the read first gate control list and the created second gate control list to the communication device 30L.

[0022] The communication device 30L stores a first GCL for a predetermined port among the multiple ports constituting the LAG, and a second GCL for ports other than the predetermined port. The communication device 30L refers to the first GCL and the second GCL to cause a flow with a fixed transmission cycle to be sent from the corresponding port. When the communication device 30L detects a failure in a faulty port among the multiple ports constituting the LAG, it transmits failure information to the control device 20. The communication device 30L receives and stores the first GCL and the second GCL, which are new GCLs created based on the failure information, from the control device 20. The first GCL defines a flow with a fixed transmission cycle to be passed through each time slot for the predetermined port, and the second GCL defines the opening of multiple time slots for ports other than the predetermined port. After a failure occurs, the communication device 30L changes the GCL it is referencing to the new first GCL and second GCL and causes a flow with a fixed transmission cycle to be sent from the corresponding port. In other words, by following the new first GCL and second GCL, the communication device 30L can permit ST flow communication in predetermined time slots on predetermined ports other than the faulty port, and permit NST flow communication on ports other than the predetermined ports. Therefore, even if a port failure occurs, the communication device 30L can flexibly continue TAS communication without, for example, the need to manually reset the GCL for the communication device 30. Thus, TAS can be applied to communication devices in which LAG is set, and the resetting of GCLs when some of the multiple ports constituting LAG fail can be made more efficient.

[0023] Referring to Figure 2, the configuration of the control device 20 according to this embodiment will be described.

[0024] The control device 20 comprises a control unit 21, a storage unit 22, a communication unit 23, an input unit 24, and an output unit 25.

[0025] The control unit 21 includes at least one processor, at least one programmable circuit, at least one dedicated circuit, or any combination thereof. The processor is a general-purpose processor such as a CPU or GPU, or a dedicated processor specialized for a specific process. "CPU" is an abbreviation for central processing unit. "GPU" is an abbreviation for graphics processing unit. The programmable circuit is, for example, an FPGA. "FPGA" is an abbreviation for field-programmable gate array. The dedicated circuit is, for example, an ASIC. "ASIC" is an abbreviation for application specific integrated circuit. The control unit 21 controls each part of the control device 20 and executes processes related to the operation of the control device 20.

[0026] The storage unit 22 includes at least one semiconductor memory, at least one magnetic memory, at least one optical memory, or any combination thereof. The semiconductor memory is, for example, RAM, ROM, or flash memory. "RAM" is an abbreviation for random access memory. "ROM" is an abbreviation for read-only memory. The RAM is, for example, SRAM or DRAM. "SRAM" is an abbreviation for static random access memory. "DRAM" is an abbreviation for dynamic random access memory. The ROM is, for example, EEPROM. "EEPROM" is an abbreviation for electrically erasable programmable read-only memory. The flash memory is, for example, SSD. "SSD" is an abbreviation for solid-state drive. The magnetic memory is, for example, HDD. "HDD" is an abbreviation for hard disk drive. The storage unit 22 functions, for example, as main memory, auxiliary memory, or cache memory. The memory unit 22 stores information used for the operation of the control device 20 and information obtained through the operation of the control device 20.

[0027] The communication unit 23 includes at least one communication module. The communication module is, for example, a module compatible with a LAN communication standard such as Ethernet®. "LAN" is an abbreviation for local area network. The communication unit 23 communicates with each communication device 30. The communication unit 23 receives information used for the operation of the control device 20 and transmits information obtained through the operation of the control device 20.

[0028] The input unit 24 includes at least one input interface. The input interface may be, for example, a physical key, a capacitive key, a pointing device, a touchscreen integrated with a display, or a microphone. The input unit 24 accepts operations to input information used for the operation of the control device 20. Instead of being provided in the control device 20, the input unit 24 may be connected to the control device 20 as an external input device. Any connection method can be used, for example, USB, HDMI®, or Bluetooth®. "USB" is an abbreviation for Universal Serial Bus. "HDMI®" is an abbreviation for High-Definition Multimedia Interface.

[0029] The output unit 25 includes at least one output interface. The output interface is, for example, a display or a speaker. The display is, for example, an LCD or an organic EL display. "LCD" is an abbreviation for Liquid Crystal Display. "EL" is an abbreviation for Electro Luminescent. The output unit 25 outputs information obtained by the operation of the control device 20. Instead of being provided in the control device 20, the output unit 25 may be connected to the control device 20 as an external output device. Any connection method can be used, for example, USB, HDMI®, or Bluetooth®.

[0030] The functions of the control device 20 are realized by executing the control program according to this embodiment on the processor acting as the control unit 21. In other words, the functions of the control device 20 are realized by software. The control program causes the computer to perform the operations of the control device 20, thereby causing the computer to function as the control device 20. That is, the computer functions as the control device 20 by performing the operations of the control device 20 according to the control program.

[0031] The program can be stored on a non-temporary computer-readable medium. Examples of non-temporary computer-readable mediums include flash memory, magnetic recording devices, optical discs, magneto-optical recording media, or ROM. The program can be distributed, for example, by selling, transferring, or lending portable media such as SD cards, DVDs, or CD-ROMs containing the program. "SD" is an abbreviation for Secure Digital. "DVD" is an abbreviation for digital versatile disc. "CD-ROM" is an abbreviation for compact disc read-only memory. The program may also be distributed by storing it in server storage and transferring it from the server to other computers. The program may also be provided as a program product.

[0032] A computer, for example, stores a program stored on a portable medium or a program transferred from a server in its main memory. Then, the computer reads the program stored in the main memory with its processor and executes the processing according to the read program. The computer may also read a program directly from the portable medium and execute the processing according to the program. The computer may also execute the processing according to the received program sequentially each time a program is transferred to it from a server. Processing may also be performed by a so-called ASP type service, which does not transfer programs from the server to the computer, but realizes its function only through execution instructions and result retrieval. "ASP" is an abbreviation for application service provider. A program includes information used for processing by an electronic computer that is equivalent to a program. For example, data that is not a direct instruction to the computer but has the nature of defining the computer's processing falls under "equivalent to a program".

[0033] Some or all of the functions of the control device 20 may be implemented by a programmable circuit or a dedicated circuit as the control unit 21. In other words, some or all of the functions of the control device 20 may be implemented by hardware.

[0034] The memory unit 22 stores the GCLs created for each port constituting the LAG of the communication device 30L. The GCLs include a first GCL that defines multiple time slots for each of the multiple ports constituting the LAG of the communication device 30L, and a flow with a fixed transmission period to pass through each time slot. The first GCLs are created in advance by a known method, for example, by a network administrator.

[0035] The control unit 21 has a GCL issuance function 211 that creates new GCLs for each port constituting the LAG of the communication device 30L. Specifically, as will be explained below, the GCL issuance function 211 is a function that allows the control unit 21 to create new GCLs for each port constituting the LAG other than the fault port indicated by the fault information. The GCL issuance function 211 includes a function in which the control unit 21 selects a first GCL for a predetermined port from the first GCLs for each port stored in the storage unit 22, further creates a second GCL that defines the release of multiple time slots for each port other than the predetermined port, generates GCL information that shows the first GCL for the selected predetermined port and the created second GCLs for each port as a single GCL set, and transmits it to the communication device 30L via the communication unit 23. By transmitting the GCL information to the communication device 30L, the control unit 21 can update the time slots that were set for each port of the communication device 30L. By pre-storing the first GCL for each port in the storage unit 22, the time required for the communication device 30L to create a new GCL to refer to and follow in the event of a failure in a port of the communication device 30L is reduced, allowing the communication device 30L to permit ST flow communication after the failure and continue TAS communication.

[0036] Referring to Figure 3, the configuration of the communication device 30L according to this embodiment will be described.

[0037] The communication device 30L includes a control unit 31, a storage unit 32, and multiple ports such as a control signal receiving port 33, a control signal transmission port 34, multiple main signal receiving ports 35, and multiple main signal transmission ports 36.

[0038] The control unit 31 includes at least one processor, at least one programmable circuit, at least one dedicated circuit, or any combination thereof. The processor is a general-purpose processor such as a CPU or GPU, or a dedicated processor specialized for a specific process. The programmable circuit is, for example, an FPGA. The dedicated circuit is, for example, an ASIC. The control unit 31 controls each part of the communication device 30 and executes processes related to the operation of the communication device 30.

[0039] The storage unit 32 includes at least one semiconductor memory, at least one magnetic memory, at least one optical memory, or any combination thereof. The semiconductor memory is, for example, RAM, ROM, or flash memory. The RAM is, for example, SRAM or DRAM. The ROM is, for example, EEPROM. The flash memory is, for example, SSD. The magnetic memory is, for example, HDD. The storage unit 32 functions, for example, as main memory, auxiliary memory, or cache memory. The storage unit 32 stores information used for the operation of the communication device 30 and information obtained by the operation of the communication device 30.

[0040] Each port is provided with or connected to at least one communication module. The communication module is, for example, a module compatible with a LAN communication standard such as Ethernet®. The control signal receiving port 33 is a port for receiving control signals transmitted from the control device 20 via the control communication network. The control signal transmitting port 34 is a port for transmitting fault information indicating a faulty port to the control device 20 via the control communication network. Each of the multiple main signal receiving ports 35 is a port for receiving main signals transmitted from other communication devices 30L via the communication network 11, which is the main signal communication network. Each of the multiple main signal transmitting ports 36 is a port for transmitting the main signals received by each of the multiple main signal receiving ports 35 to other communication devices 30L via the communication network 11, which is the main signal communication network.

[0041] The functions of the communication device 30 are realized by executing the communication program according to this embodiment on the processor acting as the control unit 31. In other words, the functions of the communication device 30 are realized by software. The communication program causes the computer to perform the operations of the communication device 30, thereby causing the computer to function as the communication device 30. That is, the computer functions as the communication device 30 by performing the operations of the communication device 30 according to the communication program.

[0042] Some or all of the functions of the communication device 30 may be implemented by a programmable circuit or a dedicated circuit as the control unit 31. In other words, some or all of the functions of the communication device 30 may be implemented by hardware.

[0043] The control unit 31 has a GCL receiving function 311 that receives GCL information, which is a control signal transmitted from the control device 20, via the control signal receiving port 33, and stores the GCLs for each port included in the GCL set indicated by the GCL information in the storage unit 32. The control unit 31 has a GCL execution function 312 that performs ST flow communication, or ST flow and NST flow communication, i.e., TAS communication, according to the GCLs for each port stored in the storage unit 32. When the control unit 31 detects a failure in at least one of the multiple main signal transmission ports 36, it has a failure information transmission function 313 that creates failure information indicating the port as a faulty port and transmits it to the control device 20. The failure information may indicate each port that constitutes the LAG other than the faulty port, in addition to the faulty port. The failure information transmission function 313 includes a port switching function that continues communication on ports other than the faulty port. The control unit 31 has a logic interface function 314 that bundles a plurality of main signal receiving ports 35 as one logic port constituting a LAG, and bundles a plurality of main signal transmission ports 36 as one logic port constituting a LAG. The logic interface function 314 includes a function to expand bandwidth by distributing the flow received from each of the plurality of main signal receiving ports 35 constituting a LAG to each of the plurality of main signal transmission ports 36 constituting a LAG. Any method may be used for flow distribution. For example, the control unit 31 may determine which main signal transmission port 36 to output according to the identifier that each frame of the flow has. When the control unit 31 detects that a faulty port has recovered from a fault, it has a recovery function 315 that changes the GCL to be referenced and followed for TAS communication from the first GCL and second GCL received from the control device 20 as described below to the first GCL and second GCL that were previously stored in the storage unit 32. The recovery function 315 includes a function to transmit recovery information indicating that the faulty port has recovered from the fault to the control device 20 via the control signal transmission port 34.

[0044] Referring to FIGS. 4 to 6, the operation of the system 10 according to the present embodiment will be described. In the present embodiment, in the storage unit 32 of the communication device 30L, for a predetermined port, a first GCL defining a flow with a constant transmission cycle to be passed through in each time slot, and a second GCL defining the release of a plurality of time slots for ports other than the predetermined port are stored. The control unit 21 of the control device 20 may store information indicating the GCL currently referred to for each port in the communication device 30L in the storage unit 22. That is, the control unit 21 may always be able to grasp the predetermined port related to the first GCL and the ports other than the predetermined port related to the second GCL among the plurality of ports in which the LAG of the communication device 30L is set.

[0045] In step S101, the control unit 31 of the communication device 30L controls the queuing of the flow and the transmission from each of the plurality of main signal transmission ports 36 according to the GCL stored in the storage unit 32 by the GCL execution function 312 and the logical interface function 314.

[0046] In step S102, the control unit 31 determines whether there is a failure in at least one of the plurality of main signal transmission ports 36 by the failure information transmission function 313. If it is determined that there is no failure, the operation of the system 10 repeats step S102. If it is determined that there is a failure, that is, when the control unit 31 detects a failure, the operation of the system 10 proceeds to step S103.

[0047] In step S103, the control unit 31 generates failure information indicating the failure port and each port constituting the LAG other than the failure port by the failure information transmission function 313, and transmits the failure information to the control device 20 via the control signal transmission port 34.

[0048] In step S104, the control unit 21 of the control device 20 receives the failure information from the communication device 30 via the communication unit 23.

[0049] In step S105, the control unit 21 identifies a new predetermined port of the communication device 30L. The new predetermined port is, for example, a port other than the fault port for which a time slot is set to allow a flow with a priority of a predetermined level or higher to pass, i.e., a port whose CoS is greater than or equal to a predetermined value. If the fault port indicated by the fault information indicates a port related to the first GCL currently referenced by the communication device 30L, i.e., the current predetermined port, the control unit 21 identifies a port other than the current predetermined port as the new predetermined port. If the fault port indicated by the fault information indicates a port related to the second GCL currently referenced by the communication device 30L, the control unit 21 may identify the current predetermined port as the new predetermined port.

[0050] Any method may be used to identify a new predetermined port. For example, the control unit 21 may identify a predetermined port by receiving port information indicating a predetermined port specified by the network administrator via the input unit 24. For example, when the control unit 21 receives port information via the input unit 24, it may also display fault information received from the communication device 30L via the output unit 25. In this embodiment, the control unit 21 identifies port No. 1 as the predetermined port among the multiple main signal receiving ports 35 that constitute the LAG of the communication device 30L.

[0051] In step S106, the control unit 21, using the GCL issuance function 211, selects and reads the first GCL for the specified predetermined port from among the first GCLs stored in the storage unit 22 for each port. The control unit 21 also creates a second GCL that defines the opening of multiple time slots for ports other than the specified predetermined port. Figure 5 shows the first GCL set NS, which is a set of first GCLs for each of the ports No. 1 to N of the communication device 30L, stored in the storage unit 22 by the control device 20. Referring to Figure 5, in the first GCL set NS, the flow to pass through in the time slots set for each port is common, and it is stipulated that communication of ST of CoS "7" is permitted in time slot 1 and ST of CoS "6" is permitted in time slot 2 for each port, and the length of time T for which communication is permitted in time slots 1 and 2 is specified.Ｃ This is specified as 10 microseconds. However, the first GCL set may have different flows to pass through each port in time slots. In this embodiment, the control unit 21 selects the first GCL related to the identified No. 1 port from the first GCL set. The control unit 21 also creates a second GCL that defines the release of multiple time slots for each of the ports other than No. 1.

[0052] Figure 6 shows the update GCL set OS, which is a set of a first GCL selected by the control unit 21 and a second GCL created by the control unit 21. Referring to Figure 6, the update GCL set OS includes the first GCL related to port No. 1 selected from the first GCL set NS, and the second GCL created for ports other than port No. 1. Not limited to the example in Figure 6, if the control unit 21 identifies a plurality of new predetermined ports in step S105, it may create an update GCL set that includes a first GCL related to each of the plurality of predetermined ports and a second GCL related to ports other than the plurality of predetermined ports.

[0053] In step S107, the control unit 21 generates GCL information indicating the update GCL set using the GCL issuance function 211 and transmits it to the communication device 30L.

[0054] In step S108, the control unit 31 of the communication device 30L receives GCL information from the control device 20 via the control signal receiving port 33 using the GCL receiving function 311. The control unit 31 stores the first GCL and second GCL for each port included in the update GCL set indicated by the GCL information in the storage unit 32 using the GCL receiving function 311.

[0055] In step S109, the control unit 31 controls the flow queuing and transmission from each of the multiple main signal transmission ports 36 that constitute the LAG, according to the first GCL and second GCL for each port received in step S108, using the GCL execution function 312 and the logical interface function 314. The control unit 31 can update the GCL for each port that it referenced before transmitting fault information to the control device 20 with the first GCL and second GCL for each port received in step S108. As described in steps S102 to S109, when the control unit 31 detects a fault in a predetermined port among the multiple ports, it can update the second GCL to the first GCL for a new predetermined port, which is one of the ports other than the predetermined port. As a result, even if a predetermined port that was permitted to communicate ST flows in the communication device 30L fails, it is possible to permit ST flow communication in another port as the new predetermined port and continue TAS communication. By adhering to the first GCL and the second GCL, the control unit 31 can control best-effort traffic on ports other than faulty ports and designated ports, and control delay-guaranteed communication on designated ports. This allows the control unit 31 to utilize bandwidth efficiently.

[0056] In step S110, the control unit 31 uses the recovery function 315 to determine whether the faulty port has recovered from the fault. If it is determined that the port has not recovered from the fault, the system 10 repeats step S110. If it is determined that the port has recovered from the fault, the system 10 proceeds to step S111.

[0057] In step S111, the control unit 31, using the recovery function 315, returns the referenced GCL from the first and second GCLs referenced in step S109 to the first and second GCLs that were pre-stored in the storage unit 32 before step S101. This improves user convenience by allowing TAS communication to be resumed on all ports constituting the LAG according to the original GCLs again after the faulty port recovers from the fault, without the need for manual reconfiguration. The control unit 31 may also use the recovery function 315 to transmit recovery information indicating that the faulty port has recovered from the fault to the control device 20 via the control signal transmission port 34. Upon receiving the recovery information, the control unit 21 of the control device 20 can grasp and manage the GCL currently applied by the communication device 30L. After that, the operation of the system 10 returns to step S101.

[0058] As one modification of this embodiment, if a predetermined port that permits ST flow communication fails, the control unit 31 of the communication device 30L may identify a different port as a new predetermined port, and change the GCL referenced by the newly identified predetermined port to the first GCL that the failed predetermined port referenced. In this case, for ports other than the new predetermined port, the control unit 31 refers to a second GCL that defines the release of multiple time slots. This allows the communication device 30L to continue TAS communication in the event of a port failure without communicating with the control device 20.

[0059] This disclosure is not limited to the embodiments described above. For example, two or more blocks described in the block diagram may be combined, or one block may be divided. Instead of executing two or more steps described in the flowchart in chronological order as described, they may be executed in parallel or in a different order, depending on the processing capacity of the device performing each step, or as necessary. For example, in the embodiments described above, it is also possible to distribute the configuration and operation of the control device 20 to a plurality of communication devices 30. Furthermore, for example, it is also possible to provide some or all of the components of the control device 20 in a representative communication device 30 among the plurality of communication devices 30. Other modifications are possible without departing from the spirit of this disclosure.

[0060] 10 System 11 Communication Network 20 Control Device 30, 30L Communication Device 21, 31 Control Unit 22, 32 Memory Unit 23 Communication Unit 24 Input Unit 25 Output Unit 33 Control Signal Receiving Port 34 Control Signal Transmission Port 35 Main Signal Receiving Port 36 Main Signal Transmission Port 211 GCL Issuance Function 311 GCL Receiving Function 312 GCL Execution Function 313 Fault Information Transmission Function 314 Logical Interface Function 315 Recovery Function

Claims

1. A control device for setting multiple time slots for each of the multiple ports of a communication device in which a link aggregation group is set to treat multiple ports as a single port, comprising: a communication unit that communicates with the communication device; a storage unit that stores a first gate control list for each of the multiple ports that defines the multiple time slots and a flow with a fixed transmission period to pass through each time slot; and a control unit that, upon receiving fault information from the communication device via the communication unit indicating at least one port among the multiple ports in which a failure has occurred, identifies a port other than the at least one port as a predetermined port based on the fault information, selects and reads the first gate control list for the predetermined port from the storage unit, creates a second gate control list that defines opening the multiple time slots for the ports other than the predetermined port, and transmits the read first gate control list and the created second gate control list to the communication device via the communication unit.

2. A control device according to claim 1, further comprising an input unit, wherein the control unit identifies the predetermined port by receiving port information indicating the predetermined port via the input unit.

3. A communication device configured with a link aggregation group that bundles multiple ports together and treats them as a single port, comprising: a storage unit; a first gate control list that stores in the storage unit a plurality of time slots for a predetermined port among the plurality of ports, and a flow with a fixed transmission period to pass through each time slot; and a second gate control list that defines opening the plurality of time slots for ports other than the predetermined port; and a control unit that refers to the first gate control list and the second gate control list and causes the flow to be sent from the corresponding port.

4. A communication device according to claim 3, wherein the control unit, upon detecting a failure of a predetermined port among the plurality of ports, updates the second gate control list to the first gate control list for one port other than the predetermined port.

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