Transmission system

Abstract

To provide a transmission system having an excellent packet loss countermeasure that can be generated for a long period.SOLUTION: A transmission system according to an embodiment, comprises: a first switch IC; and a second switch IC. The first switch IC is connected to a plurality of trunk lines. The second switch IC is connected to the first switch IC via a plurality of branch lines. The first switch IC comprises: a controller; a switch; a first port group; and a second port group. The controller designates one of a redundancy connection of a trunk line route for connecting a predetermined first port of the first port group with a predetermined second port of the second port group and a relay connection of the trunk line route for connecting to between two first ports of the first port group. The switch connects the predetermined first port of the first port group on the basis of the designation and the predetermined second port of the second port group, or between the two first ports of the first port group.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] An embodiment of the present invention relates to a transmission system. [Background technology]

[0002] In trunk line transmission of vehicle Ethernet networks, with the development of multimedia information inside vehicles, a communication speed of 100 Mbps is becoming insufficient, and 1 Gbps lines are increasingly being adopted.

[0003] Ethernet (registered trademark) standards that achieve a communication speed of 1 Gbps include 1000BASE-T and 1000BASE-Tx. With 1000BASE-T, transmission and reception are not physically separate, and transmission and reception are carried out simultaneously using half-duplex communication over four pairs of cables. On the other hand, 1000BASE-Tx, like 100BASE-Tx, physically separates transmission and reception, making it easier to design network equipment than 1000BASE-T, but 1000BASE-Tx communication requires a Category 6 or higher cable.

[0004] For these reasons, 1000BASE-T has become widespread. 1000BASE-T, which has been adopted by RFC (request for comments) and is widely used, is also used for the 1 Gbps lines of vehicle Ethernet networks. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2018-101887 A Summary of the Invention [Problem to be solved by the invention]

[0006] IEC61375-2-5 defines the incorporation of a bypass relay function in the trunk transmission line (ETB) of an Ethernet network in a vehicle. When the transmission route changes by switching the bypass relay, it is easy to determine the frame delimiter and it is possible to minimize packet loss because transmission and reception are physically separated in the case of a 100BASE-Tx line.

[0007] However, in the case of 1000BASE-T lines, which are widely used in Ethernet, transmission and reception are not physically separated and transmission signals cannot be easily identified. Therefore, when a route switch is performed using a bypass relay on a main transmission line, it takes a long time to restore the normal state, which can result in long periods of packet loss.

[0008] An object of the present invention is to provide a transmission system that is excellent in dealing with packet loss that may occur over a long period of time. [Means for solving the problem]

[0009] The transmission system according to the embodiment includes a first switch IC and a second switch IC. The first switch IC is connected to a plurality of trunk lines. The second switch IC is connected to the first switch IC via a plurality of branch lines. The first switch IC includes a controller, a switch, a first port group, and a second port group. The first port group includes a plurality of first ports connected to the plurality of trunk lines. The second port group includes a plurality of second ports connected to the plurality of branch lines. The controller specifies one of a redundant connection of a trunk path connecting a predetermined first port of the first port group and a predetermined second port of the second port group, and a relay connection of a trunk path connecting two first ports of the first port group. The switch connects a predetermined first port of the first port group and a predetermined second port of the second port group based on the specification of the redundant connection, and connects the two first ports of the first port group based on the specification of the relay connection. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a block diagram showing a schematic configuration of a first switch IC according to the first embodiment. [Diagram 2] FIG. 2 is a block diagram showing a schematic configuration of the second switch IC according to the first embodiment. [Diagram 3] FIG. 3 is a diagram for explaining an example of the operation of the trunk transmission system in the initial state in which no communication abnormality occurs in the first embodiment. [Figure 4] FIG. 4 is a diagram for explaining an example of the operation of the trunk transmission system in a state in which a communication abnormality occurs in the first embodiment. [Diagram 5] FIG. 5 is a diagram for explaining an example of the operation of the trunk transmission system in the initial state in which no power supply abnormality occurs in the second embodiment. [Figure 6] FIG. 6 is a diagram for explaining an example of the operation of the trunk transmission system in a state in which a power supply abnormality occurs in the second embodiment. [Figure 7] FIG. 7 is a diagram for explaining an example of the operation of the trunk transmission system in the initial state in which no abnormality occurs in the third embodiment. [Figure 8] FIG. 8 is a diagram for explaining an example of the operation of the trunk transmission system in a state in which a communication abnormality occurs in the third embodiment. [Figure 9] FIG. 9 is a diagram for explaining an example of the operation of the trunk transmission system in a state in which a power supply abnormality occurs in the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, each embodiment will be described with reference to the drawings. For example, the trunk transmission system of each embodiment can be applied to trunk transmission of a vehicle Ethernet network. (First embodiment) The first embodiment will be described with reference to FIGS.

[0012] Two switch ICs (integrated circuits) according to the first embodiment will be described with reference to Figures 1 and 2. First, the switch IC1 (first switch IC) will be described with reference to Figure 1, and then the switch IC2 (second switch IC) will be described with reference to Figure 2. For example, the switch IC1 is smaller than the switch IC2.

[0013] FIG. 1 is a block diagram showing a schematic configuration of a first switch IC according to the first embodiment. As shown in FIG. 1, a switch IC1 which is a first switch IC includes a storage unit 11, a controller unit 12, a switch unit 13, and a plurality of ports 14 (14-1 to 14-8).

[0014] The storage unit 11 is a non-volatile memory. The storage unit 11 stores an operation control program of the controller unit 12 and the like. The operation control program controls an operation for designating one of a redundant connection of the trunk path and a relay connection of the trunk path according to various conditions. An example of the redundant connection of the trunk path and the relay connection of the trunk path will be described later.

[0015] The controller unit 12 is one or more central processing units (CPUs). The controller unit 12 operates based on an operation control program stored in the storage unit 11, and controls the switching of the connections between the ports 14 by the switch unit 13. That is, based on the operation control program, the controller unit 12 specifies one of a redundant connection of the trunk path and a relay connection of the trunk path in accordance with various conditions, and controls the switching of the connections between the ports 14 by the switch unit 13. An example of the connection switching control in accordance with conditions will be described later.

[0016] The switch unit 13 is a circuit that switches the connection between the ports 14 based on an instruction from the controller unit 12. The switch unit 13 switches the connection between the ports 14 based on an instruction from the controller unit 12, and realizes one of the redundant connection of the trunk path and the relay connection of the trunk path.

[0017] The switch IC1 also has a VLAN (virtual local area network) function, and uses the VLAN function to create virtual LAN segments. An example of the VLAN function will be described later.

[0018] FIG. 2 is a block diagram showing a schematic configuration of the second switch IC according to the first embodiment. As shown in FIG. 2, a switch IC2 which is a second switch IC includes a storage unit 21, a controller unit 22, a switch unit 23, and a plurality of ports 24 (24-1 to 24-12).

[0019] The storage unit 21 is a non-volatile memory. The storage unit 21 stores an operation control program and the like for the controller unit 22. The controller unit 22 is one or more CPUs. The controller unit 22 operates based on the operation control program and the like stored in the storage unit 21, and controls switching of the connections between the ports 24 by the switch unit 23. The switch unit 23 is a circuit that switches the connections between the ports 24 based on an instruction from the controller unit 22.

[0020] The switch IC2 has a link aggregation function, and uses the link aggregation function to bundle multiple physical links into one logical link. An example of the link aggregation function will be described later.

[0021] 3 and 4 are diagrams illustrating an example of a trunk transmission system according to the first embodiment. For example, each of a plurality of cars constituting a train is equipped with the trunk transmission system, enabling communication between a higher-level management device and the cars (each car). Fig. 3 is a diagram for explaining an example of operation of the trunk transmission system in an initial state in which no communication abnormality occurs in the first embodiment, and Fig. 4 is a diagram for explaining an example of operation of the trunk transmission system in a state in which a communication abnormality occurs in the first embodiment.

[0022] As shown in FIG. 3, the trunk transmission system includes a switch IC1 and a switch IC2.

[0023] The switch IC1 is connected to a plurality of trunks, namely, trunk lines M11-1, M11-2, M12-1, and M12-2, and the switch IC2 is connected to the switch IC1 via a plurality of branch lines, namely, branch lines B11-1 to B11-4.

[0024] The trunk transmission system according to the first embodiment may be configured to include a plurality of trunks M11-1, M11-2, M12-1, and M12-2, and a plurality of branch lines B11-1 to B11-4.

[0025] For convenience of explanation, first and second port groups are defined below. The first port group includes four ports, ports 14-1 to 14-4, and the second port group includes four ports, ports 14-5 to 14-8. Note that when the ports 14-1 to 14-8 are not to be individually distinguished, they are referred to as ports 14.

[0026] Trunk M11-1 is connected to port 14-2, trunk M11-2 is connected to port 14-3, trunk M12-1 is connected to port 14-1, and trunk M12-2 is connected to port 14-4. Also, branch B11-1 has one end connected to port 14-5 and the other end connected to port 24 of switch IC2. Branch B11-2 has one end connected to port 14-6 and the other end connected to port 24 of switch IC2. Branch B11-3 has one end connected to port 14-7 and the other end connected to port 24 of switch IC2. Branch B11-4 has one end connected to port 14-8 and the other end connected to port 24 of switch IC2.

[0027] The controller unit 12 executes one of redundancy control and relay control of the trunk path in accordance with various conditions. That is, the controller unit 12 designates one of redundant connection of the trunk path and relay connection of the trunk path in accordance with various conditions.

[0028] As shown in FIG. 3, for example, in an initial state or in a state in which no communication abnormality is detected, the controller unit 12 specifies a redundant connection of a trunk path connecting a specified port 14 of a first port group and a specified port 14 of a second port group.

[0029] That is, the controller unit 12 instructs the connections between the ports 14-1 and 14-5, the ports 14-2 and 14-6, the ports 14-3 and 14-7, and the ports 14-4 and 14-8.

[0030] The controller unit 12, using the VLAN function, assigns the same VLAN ID to ports 14-1 and 14-5, 14-2 and 14-6, 14-3 and 14-7, and 14-4 and 14-8, thereby achieving redundant connections of the trunk paths.

[0031] The switch unit 13 connects a predetermined port 14 of the first port group to a predetermined port 14 of the second port group based on a redundant connection designation from the controller unit 12. That is, the switch unit 13 connects ports 14-1 and 14-5, ports 14-2 and 14-6, ports 14-3 and 14-7, and ports 14-4 and 14-8.

[0032] 4, the controller unit 12 specifies a change from redundant connection to relay connection mode based on detection of a communication abnormality with the switch IC2. That is, the controller unit 12 instructs the connection of ports 14-1 and 14-4, and ports 14-2 and 14-3. If communication between the switch IC1 and the switch IC2 becomes impossible due to some factor, the controller unit 12 detects an abnormality in packet transmission and reception, and reassigns the same VLAN ID to ports 14-1 and 14-4, and to ports 14-2 and 14-3, thereby realizing a relay connection of the trunk path.

[0033] The switch unit 13 connects two ports 14 in the first port group based on a connection method change instruction from the controller unit 12. That is, the switch unit 13 connects ports 14-1 and 14-4, and ports 14-2 and 14-3. As a result, trunks M12-1 and M12-2 are connected, and trunks M11-1 and M11-2 are connected.

[0034] Furthermore, the controller unit 12 instructs a change from the relay connection method to the redundant connection based on the detection of the resolution of the communication abnormality with the switch IC 2. That is, the controller unit 12 instructs the connections of the ports 14-1 and 14-5, the ports 14-2 and 14-6, the ports 14-3 and 14-7, and the ports 14-4 and 14-8.

[0035] Furthermore, the switch unit 13 connects ports 14-1 and 14-5, ports 14-2 and 14-6, ports 14-3 and 14-7, and ports 14-4 and 14-8 based on a change instruction for the connection method from the controller unit 12. As a result, the trunk M12-1 and branch line 11-1 are connected, the trunk M12-2 and branch line 11-4 are connected, the trunk M11-1 and branch line 11-2 are connected, and the trunk M11-2 and branch line 11-3 are connected.

[0036] As described above, the trunk transmission system according to the first embodiment changes the communication path without affecting transmission and reception at the port by controlling the routing part in the switch IC1. This enables faster switching than the bypass relay method, and data can be transmitted without causing long-term packet loss.

[0037] Second Embodiment The second embodiment will be described with reference to Figures 5 and 6. For example, each of a plurality of cars constituting a train configuration is equipped with a trunk transmission system, enabling communication between a higher-level management device and the cars (each car).

[0038] The basic configuration of the switch IC1 according to the second embodiment is substantially the same as that shown in Fig. 1. For example, the switch IC1 according to the second embodiment includes a plurality of ports 14 (14-11 to 13-14). The basic configuration of the switch IC2 according to the second embodiment is as shown in Fig. 2.

[0039] 5 and 6 are diagrams illustrating an example of a trunk transmission system according to the second embodiment. Fig. 5 is a diagram for explaining an example of operation of the trunk transmission system in an initial state in which no power supply abnormality occurs in the second embodiment. Also, Fig. 6 is a diagram for explaining an example of operation of the trunk transmission system in a state in which a power supply abnormality occurs in the second embodiment.

[0040] As shown in FIG. 5, the trunk transmission system includes a switch IC1, a switch IC2, and a bypass relay circuit 3.

[0041] The switch IC1 is connected to the trunks M21-1 and M21-2 which are a plurality of first trunks, and the bypass relay circuit 3 is connected to the trunks M22-1 and M22-2 which are a plurality of second trunks.

[0042] The switch IC2 is connected to the switch IC1 via branches B21-1 and B21-2 which are a plurality of first branches, and is connected to the bypass relay circuit 3 via branches B22-1 and B22-2 which are a plurality of second branches.

[0043] The trunk transmission system according to the second embodiment may be configured to include a plurality of trunks M21-1 and M21-2, a plurality of trunks M22-1 and M22-2, a plurality of branch lines B21-1 and B21-2, and a plurality of branch lines B22-1 and B22-2.

[0044] The trunk M21-1, the trunk M21-2, the branch B21-1, and the branch B21-2 transmit signals at a first communication speed, while the trunk M22-1, the trunk M22-2, the branch B22-1, and the branch B22-2 transmit signals at a second communication speed that is slower than the first communication speed.

[0045] For example, trunk line M21-1, trunk line M21-2, branch line B21-1, and branch line B21-2 are 1000BASE-T cables that realize a communication speed of 1 Gbps. In a 1000BASE-T cable, transmission and reception are not physically separated, and data is transmitted and received by half-duplex communication.

[0046] For example, trunk line M22-1, trunk line M22-2, branch line B22-1, and branch line B22-2 are 100BASE-Tx cables that realize a communication speed of 100 Mbps. In a 100BASE-Tx cable, transmission and reception are physically separated, and data is transmitted and received by full-duplex communication.

[0047] Furthermore, switch IC2 uses its link aggregation function to bundle branch line B21-1 from switch IC1 and branch line B22-1 from bypass relay circuit 3 as one logical link, and also bundles branch line B21-2 from switch IC1 and branch line B22-2 from bypass relay circuit 3 as one logical link. In other words, switch IC2 uses its link aggregation function to treat two physical cables as a single virtual cable, enabling communication at 1 Gbps.

[0048] For convenience of explanation, first to fourth port groups are defined below. The first port group includes two ports, ports 14-11 and 14-12, the second port group includes two ports, ports 14-13 and 14-14, the third port group includes two ports, ports 34-1 and 34-2, and the fourth port group includes two ports, ports 34-3 and 34-4.

[0049] When the ports 14-11 to 14-14 are not distinguished from one another, they are referred to as ports 14. When the ports 34-1 to 34-4 are not distinguished from one another, they are referred to as ports 34.

[0050] The trunk M21-1 is connected to the port 14-11, and the trunk M21-2 is connected to the port 14-12. In addition, the trunk M22-1 is connected to the port 34-1, and the trunk M22-2 is connected to the port 34-2.

[0051] One end of branch line B21-1 is connected to port 14-13 and the other end is connected to port 24 of switch IC2. One end of branch line B21-2 is connected to port 14-14 and the other end is connected to port 24 of switch IC2. In addition, one end of branch line B22-1 is connected to port 34-3 and the other end is connected to port 24 of switch IC2. Branch line B22-2 is connected to port 34-4 and the other end is connected to port 24 of switch IC2.

[0052] 5, in the initial state or in a state where no communication abnormality is detected, the controller unit 12 specifies a redundant connection of the trunk path connecting a predetermined port 14 of the first port group and a predetermined port 14 of the second port group. That is, the controller unit 12 instructs the connection of port 14-11 and port 14-13, and port 14-12 and port 14-14. The controller unit 12 realizes a redundant connection of the trunk path by assigning the same VLAN ID to ports 14-11 and 14-13 and to ports 14-12 and 14-14 using the VLAN function.

[0053] The switch unit 13 connects a predetermined port 14 of the first port group to a predetermined port 14 of the second port group based on a redundant connection designation from the controller unit 12. That is, the switch unit 13 connects port 14-11 to port 14-13, and port 14-12 to port 14-15.

[0054] Furthermore, the controller unit 12 specifies a change from the redundant connection to the relay connection method based on the detection of a communication abnormality with the switch IC2. That is, the controller unit 12 instructs the connection of the port 14-11 and the port 14-12. If communication between the switch IC1 and the switch IC2 becomes impossible due to some factor, the controller unit 12 detects an abnormality in the transmission and reception of packets and reassigns the same VLAN ID to the ports 14-11 and 14-12, thereby realizing a relay connection of the trunk path.

[0055] The switch unit 13 connects two ports 14 in the first port group based on a connection method change instruction from the controller unit 12. That is, the switch unit 13 connects the port 14-11 and the port 14-12.

[0056] Furthermore, the controller unit 12 instructs a change from the relay connection method to the redundant connection based on detection of the resolution of the communication abnormality with the switch IC 2. That is, the controller unit 12 instructs the connection between the port 14-1 and the port 14-3, and the port 14-2 and the port 14-4.

[0057] Furthermore, the switch unit 13 connects the ports 14-1 and 14-3, and the ports 14-2 and 14-4, based on a connection method change instruction from the controller unit 12. As a result, the trunk M21-1 and the branch B21-1 are connected, and the trunk M21-2 and the branch B21-2 are connected.

[0058] Furthermore, the bypass relay circuit 3 selectively executes a redundant connection of the trunk path and a relay connection of the trunk path according to the state of the power supply. The redundant connection of the trunk path connects a predetermined port 34 of the third port group to a predetermined port 34 of the fourth port group. Furthermore, the relay connection of the trunk path connects two ports 34 of the third port group.

[0059] That is, as shown in FIG. 5, when power is being supplied normally, the bypass relay circuit 3 executes a redundant connection of the main line path, connecting the ports 34-1 and 34-3, and the ports 34-2 and 34-4.

[0060] Furthermore, as shown in FIG. 6, when an abnormality occurs in the power supply and the power supply is cut off, the bypass relay circuit 3 switches the redundant connection to the relay connection and connects between the port 34-1 and the port 34-2.

[0061] In addition, when the power supply is restored to a normal state from a state in which the power supply is cut off, the bypass relay circuit 3 switches the relay connection to a redundant connection, connecting ports 34-1 and 34-3, and ports 34-2 and 34-4.

[0062] As described above, in the trunk transmission system according to the second embodiment, when a power supply abnormality occurs, the 100 Mbps trunks M22-1 and M22-2 can be immediately restored and transmission can be resumed by switching the bypass relay circuit 3. This makes it possible to reduce the time during which transmission is disabled when switching the route.

[0063] (Third embodiment) The third embodiment will be described with reference to Figures 7 to 9. For example, each of a plurality of cars constituting a train configuration is equipped with a trunk transmission system, enabling communication between a higher-level management device and the cars (each car).

[0064] The basic configuration of a switch IC1 according to the third embodiment is similar to that shown in Fig. 1. Moreover, the basic configuration of a switch IC2 according to the third embodiment is as shown in Fig. 2.

[0065] 7 to 9 are diagrams illustrating an example of a trunk transmission system according to the third embodiment. Fig. 7 is a diagram for explaining an example of operation of the trunk transmission system in an initial state in which no abnormality occurs in the third embodiment. Fig. 8 is a diagram for explaining an example of operation of the trunk transmission system in a state in which a communication abnormality occurs in the third embodiment. Fig. 9 is a diagram for explaining an example of operation of the trunk transmission system in a state in which a power supply abnormality occurs in the third embodiment.

[0066] As shown in FIG. 7, the trunk transmission system includes a switch IC1, a switch IC2, and a bypass relay circuit 3.

[0067] The bypass relay circuit 3 is connected to trunk lines M21-1 and M21-2 which are a plurality of first trunk lines, and is also connected to trunk lines M22-1 and M22-2 which are a plurality of second trunk lines.

[0068] Switch IC1 is connected to bypass relay circuit 3 via a plurality of first branches B21-1 and B21-2 and a plurality of second branches B22-1 and B22-2, and is connected to switch IC2 via a plurality of third branches B23-1 and B23-2 and a plurality of fourth branches B24-1 and B24-2.

[0069] The trunk transmission system according to the third embodiment may be configured to include a plurality of trunks M21-1, M21-2, M22-1, and M22-2, and a plurality of branch lines B21-1, B21-2, B22-1, B22-2, B23-1, B23-2, B24-1, and B24-2.

[0070] The trunk M21-1, the trunk M21-2, the branch B21-1, the branch B21-2, the branch B23-1, and the branch B23-2 transmit signals at a first communication speed. The trunk M22-1, the trunk M22-2, the branch B22-1, the branch B22-2, the branch B24-1, and the branch B24-2 transmit signals at a second communication speed that is slower than the first communication speed.

[0071] For example, trunk line M21-1, trunk line M21-2, branch line B21-1, branch line B21-2, branch line B23-1, and branch line B23-2 are 1000BASE-T cables that achieve a communication speed of 1 Gbps. In a 1000BASE-T cable, transmission and reception are not physically separated, and data is transmitted and received by half-duplex communication.

[0072] For example, trunk line M22-1, trunk line M22-2, branch line B22-1, branch line B22-2, branch line B24-1, and branch line B24-2 are 100BASE-Tx cables that realize a communication speed of 100 Mbps. In a 100BASE-Tx cable, transmission and reception are physically separated, and data is transmitted and received by full-duplex communication.

[0073] Furthermore, switch IC2 uses its link aggregation function to bundle branch line B23-1 from switch IC1 and branch line B24-1 from bypass relay circuit 3 as one logical link, and also bundles branch line B23-2 from switch IC1 and branch line B24-2 from bypass relay circuit 3 as one logical link. In other words, switch IC2 uses its link aggregation function to treat two physical cables as a single virtual cable, enabling communication at 1 Gbps.

[0074] Here, for convenience of explanation, first to fourth port groups are defined. The first port group includes two ports, ports 34-1 and 34-2, and the second port group includes two ports, ports 34-3 and 34-4. The third port group includes two ports, ports 34-5 and 34-6, and the fourth port group includes two ports, ports 34-7 and 34-8. Note that when the ports 34-1 to 34-8 are not to be individually distinguished, they are referred to as ports 34.

[0075] Furthermore, fifth to eighth port groups are defined. The fifth port group includes two ports, ports 14-1 and 14-2, and the sixth port group includes two ports, ports 14-3 and 14-4. The seventh port group includes two ports, ports 14-5 and 14-6, and the eighth port group includes two ports, ports 14-7 and 14-8. Note that when the ports 14-1 to 14-8 are not to be individually distinguished, they are referred to as ports 14.

[0076] The trunk M21-1 is connected to a port 34-1, and the trunk M21-2 is connected to a port 34-2. In addition, the trunk M22-1 is connected to a port 34-3, and the trunk M22-2 is connected to a port 34-4.

[0077] Branch line B21-1 connects port 34-5 to port 14-1, branch line B21-2 connects port 34-6 to port 14-2, branch line B22-1 connects port 34-7 to port 14-3, and branch line B22-2 connects port 34-8 to port 14-4.

[0078] One end of branch line B23-1 is connected to port 14-5 and the other end is connected to port 24 of the switch IC. Branch line B23-2 is connected to port 14-6 and the other end is connected to port 24 of the switch IC. Branch line B24-1 is connected to port 14-7 and the other end is connected to port 24 of the switch IC. Branch line B24-2 is connected to port 14-8 and the other end is connected to port 24 of the switch IC.

[0079] The bypass relay circuit 3 selectively executes a redundant connection of the trunk path and a relay connection of the trunk path according to the state of the power supply. The redundant connection of the trunk path connects a predetermined port 34 of the first port group to a predetermined port 34 of the third port group, and connects a predetermined port 34 of the second port group to a predetermined port 34 of the fourth port group. Furthermore, the relay connection of the trunk path connects two ports 34 of the first port group, and connects two ports 34 of the second port group.

[0080] When power is being supplied normally, the bypass relay circuit 3 performs redundant connections of the main paths, connecting ports 34-1 and 34-5, ports 34-2 and 34-6, ports 34-3 and 34-7, and ports 34-4 and 34-8.

[0081] In addition, in the initial state or in a state where no communication abnormality is detected, the controller unit 12 of the switch IC1 connects a predetermined port 14 in the fifth port group to a predetermined port 14 in the seventh port group, and specifies a redundant connection of a trunk path connecting a predetermined port 14 in the sixth port group to a predetermined port 14 in the eighth port group.

[0082] That is, the controller unit 12 instructs the connections between the ports 14-1 and 14-5, the ports 14-2 and 14-6, the ports 14-3 and 14-7, and the ports 14-4 and 14-8.

[0083] The controller unit 12 uses the VLAN function to assign the same VLAN ID to ports 14-1 and 14-5, ports 14-2 and 14-6, ports 14-3 and 14-7, and ports 14-4 and 14-8, thereby achieving redundant connections of the trunk paths.

[0084] The switch unit 13 connects a predetermined port 14 in the fifth port group to a predetermined port 14 in the seventh port group, and connects a predetermined port 14 in the sixth port group to a predetermined port 14 in the eighth port group, based on a redundant connection designation from the controller unit 12. That is, the switch unit 13 connects port 14-1 to port 14-5, port 14-2 to port 14-6, port 14-3 to port 14-7, and port 14-4 to port 14-8.

[0085] Furthermore, the controller unit 12 specifies a change from the redundant connection to the relay connection method based on the detection of a communication abnormality with the switch IC2. That is, the controller unit 12 instructs the connection of the ports 14-1 and 14-2, and the connection of the ports 14-3 and 14-4. If communication between the switches IC1 and IC2 becomes impossible due to some factor, the controller unit 12 detects an abnormality in the transmission and reception of packets, and reassigns the same VLAN ID to the ports 14-1 and 14-2, and to the ports 14-3 and 14-4, thereby realizing a relay connection of the trunk path.

[0086] The switch unit 13 connects two ports 14 in the fifth port group and connects two ports 14 in the sixth port group based on a connection method change instruction from the controller unit 12. That is, the switch unit 13 connects port 14-1 and port 14-2, and connects port 14-3 and port 14-4.

[0087] Furthermore, the controller unit 12 instructs a change from the relay connection method to the redundant connection based on the detection of the resolution of the communication abnormality with the switch IC 2. That is, the controller unit 12 instructs the connections of the ports 14-1 and 14-5, the ports 14-2 and 14-6, the ports 14-3 and 14-7, and the ports 14-4 and 14-8.

[0088] Furthermore, the switch unit 13 connects ports 14-1 and 14-5, ports 14-2 and 14-6, ports 14-3 and 14-7, and ports 14-4 and 14-8 based on a change instruction for the connection method from the controller unit 12. As a result, the trunk M21-1, branch B21-1, and branch B23-1 are connected, the trunk M21-2, branch B21-2, and branch B23-2 are connected, the trunk M22-1, branch B22-1, and branch B24-1 are connected, and the trunk M22-2, branch B22-2, and branch B24-2 are connected.

[0089] As shown in Figures 7 and 8, when power is being supplied normally, the bypass relay circuit 3 connects ports 34-1 and 34-5, ports 34-2 and 34-6, ports 34-3 and 34-7, and ports 34-4 and 34-8.

[0090] Furthermore, as shown in FIG. 9, when an abnormality occurs in the power supply and the power supply is cut off, the bypass relay circuit 3 switches the redundant connection to a relay connection, connecting ports 34-1 and 34-2, and connecting ports 34-3 and 34-4.

[0091] In addition, when the power supply is restored to a normal state from a state in which the power supply is cut off, the bypass relay circuit 3 switches the relay connection to a redundant connection, connecting ports 34-1 and 34-5, ports 34-2 and 34-6, ports 34-3 and 34-7, and ports 34-4 and 34-8.

[0092] As described above, the trunk transmission system according to the third embodiment responds to the cause of an abnormality in two stages, that is, the bypass relay circuit 3 and the switch IC2.

[0093] In response to the occurrence of a communication abnormality that makes it impossible to communicate between switches IC2 and IC1 due to some factor, the trunk transmission system can change the route and continue transmission without incurring long periods of packet loss by using the VLAN function of switch IC1.

[0094] Furthermore, in response to the occurrence of a power supply abnormality, the trunk transmission system can instantly restore the 100Mbps trunks M22-1 and M22-2 and resume transmission even if the 1Gbps trunks M21-1 and M21-2 are temporarily unable to transmit by switching the bypass relay circuit 3. Therefore, with the trunk transmission system, the state in which operation must be performed using only the 100Mbps trunks can be made temporary, making it possible to make the most of the bandwidth.

[0095] In addition, in a situation where the bandwidth is narrowed as shown in Figures 6 and 9, the trunk transmission systems according to the second and third embodiments may use packet priority control (QoS) in order to transmit important data (control command transmission) as reliably as possible. By adding a mechanism for preferentially transmitting important data, it is possible to minimize the impact even when the bandwidth is reduced.

[0096] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0097] 1...Switch IC 2. Switch IC 3...Bypass relay circuit 11...Storage section 12…Controller section 13...Switch section 14…Port 21...Storage section 22…Controller section 23...Switch section 24…Port 34…Port B11-1, B11-2, B11-3, B11-4...Branch line B21-1, B21-2…branch line B22-1, B22-2…branch line B23-1, B23-2…branch line B24-1, B24-2…branch line M11-1, M11-2…Main line M12-1, M12-2…Main line M21-1, M21-2...Main line M22-1, M22-2...Main line

Claims

1. a first switch IC connected to a plurality of trunk lines; a second switch IC connected to the first switch IC via a plurality of branch lines; The first switch IC includes: A controller; Switch, a first port group including a plurality of first ports connected to the plurality of trunk lines; a second port group including a plurality of second ports connected to the plurality of branch lines; the controller designates one of a redundant connection of a trunk path connecting a predetermined first port of the first port group and a predetermined second port of the second port group, and a relay connection of a trunk path connecting two first ports of the first port group; a switch that connects a predetermined first port of the first port group to a predetermined second port of the second port group based on a specification of a redundant connection, and connects two first ports of the first port group based on a specification of a relay connection.

2. 2. The transmission system according to claim 1, wherein the controller specifies a redundant connection in an initial state, and specifies a change from the redundant connection to a relay connection upon detection of a communication abnormality with the second switch IC.

3. The transmission system according to claim 1 , wherein the first switch IC performs a redundant connection and a relay connection by using a VLAN function.

4. a first switch IC connected to a plurality of first trunk lines; a bypass relay circuit connected to the plurality of second trunk lines; a second switch IC connected to the first switch IC via a plurality of first branch lines and connected to the bypass relay circuit via a plurality of second branch lines; The first switch IC includes: A controller; Switch, a first port group including a plurality of first ports connected to the first trunk line; a second port group including a plurality of second ports connected to the first branch line; The bypass relay circuit includes: a third port group including a plurality of third ports connected to the second trunk line; a fourth port group including a plurality of fourth ports connected to the second branch line; the controller specifies a redundant connection of a trunk path connecting a predetermined first port of the first port group and a predetermined second port of the second port group; the switch connects a predetermined first port of the first port group and a predetermined second port of the second port group based on a designation of a redundant connection; a bypass relay circuit selectively performs a redundant connection of a trunk path connecting a predetermined third port of the third port group and a predetermined fourth port of the fourth port group, and a relay connection of a trunk path connecting two third ports of the third port group, depending on a state of power supply.

5. The transmission system according to claim 4 , wherein the bypass relay circuit switches the redundant connection to the relay connection when the power supply is interrupted.

6. the first trunk line and the first branch line have a first communication speed; 5. The transmission system according to claim 4, wherein the second trunk line and the second branch line have a second communication speed that is slower than the first communication speed.

7. the first trunk line and the first branch line transmit and receive data by half-duplex communication; the second trunk line and the second branch line transmit and receive data by full-duplex communication; 5. The transmission system according to claim 4, wherein the second switch IC regards the first branch line from the first switch IC and the second branch line from the bypass relay circuit as one logical link by a link aggregation function.

8. a bypass relay circuit connected to the plurality of first trunk lines and the plurality of second trunk lines; a first switch IC connected to the bypass relay circuit via a plurality of first branch lines and a plurality of second branch lines; a second switch IC connected to the first switch IC via a plurality of third branch lines and a plurality of fourth branch lines; The first switch IC includes: A controller; Switch, a first port group including a plurality of first ports connected to the plurality of first branch lines; a second port group including a plurality of second ports connected to the plurality of second branch lines; a third port group including a plurality of third ports connected to the plurality of third branch lines; a fourth port group including a plurality of fourth ports connected to the plurality of fourth branch lines; the controller specifies one of a redundant connection of a trunk path that connects a predetermined first port of the first port group and a predetermined third port of the third port group and also connects a predetermined second port of the second port group and a predetermined fourth port of the fourth port group, and a relay connection of a trunk path that connects two first ports of the first port group and connects two second ports of the second port group; a switch that connects a predetermined first port of the first port group to a predetermined third port of the third port group based on a redundant connection specification, and connects a predetermined second port of the second port group to a predetermined fourth port of the fourth port group based on a relay connection specification, and that connects two first ports of the first port group and connects two second ports of the second port group.

9. 9. The transmission system according to claim 8, wherein the controller specifies a redundant connection in an initial state, and specifies a change from the redundant connection to a relay connection upon detection of a communication abnormality with the second switch IC.

10. The bypass relay circuit includes: a fifth port group including a plurality of fifth ports connected to the first trunk line; a sixth port group including a plurality of sixth ports connected to the second trunk line; a seventh port group including a plurality of seventh ports connected to the first branch line; an eighth port group including a plurality of eighth ports connected to the second trunk line; 9. The transmission system of claim 8, wherein the bypass relay circuit selectively performs, depending on a state of power supply, a redundant connection of a trunk path that connects a predetermined fifth port of the fifth port group and a predetermined seventh port of the seventh port group and connects a predetermined sixth port of the sixth port group and a predetermined eighth port of the eighth port group, and a relay connection of a trunk path that connects between two first ports of the fifth port group and connects between two sixth ports of the sixth port group.

11. The transmission system according to claim 10 , wherein the bypass relay circuit switches the redundant connection to the relay connection when a power supply is interrupted.

12. the first trunk, the first branch, and the third branch are at a first communication speed; 9. The transmission system according to claim 8, wherein the second trunk line, the second branch line, and the fourth branch line have a second communication speed that is slower than the first communication speed.

13. the first trunk line, the first branch line, and the third branch line transmit and receive data by half-duplex communication; the second trunk line, the second branch line, and the fourth branch line transmit and receive data by full-duplex communication; 9. The transmission system according to claim 8, wherein the second switch IC regards the third branch line and the fourth branch line from the first switch IC as one logical link by a link aggregation function.

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