JP2014011604A - Ring/star type ethernet system, ring/star type switch, and frame transfer control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To immediately resume communication by using a ring/star type switch for relaying and connecting ring wiring and star wiring together with the other ring/star type switch, when a failure occurs in the other ring/star type switch.SOLUTION: A ring/star type switch SW 10 duplicates a frame to be transferred to a switching hub HUB 1 and transfers the duplicated frame to a ring/star type switch SW 20 when the SW 10 is operating as an active system, and transfers a frame received from the SW 20 to the HUB 1 when the SW 10 is operating as a standby system. The SW 20 duplicates a frame to be transferred to a switching hub HUB 2 and transfers the duplicated frame to the SW 10 when the SW 20 is operating as an active system, and transfers a frame received from the SW 10 to the HUB 2 when the SW 20 is operating as a standby system.

Description

  The present invention relates to an Ethernet (registered trademark) communication technique, and more particularly to a control technique for a ring / star Ethernet system that relay-connects a ring Ethernet and a star Ethernet.

In a monitoring and control system that monitors and controls building facilities and plant facilities, communication equipment having various functions such as information collection and control functions is used as nodes for redundant connection in a communication network, and central monitoring is performed based on information from these nodes. The equipment monitors and controls each piece of equipment.
In such Ethernet systems such as monitoring and control systems, the topology of connecting nodes is a ring type in which each node is connected in a ring shape with a communication cable, and each node is radially connected with a communication cable to a concentrator such as a switching hub. There is a star type to connect to.

Here, in the case of the ring type, an STP (Spanning Tree Protocol / IEEE 802.1D) function for avoiding a communication error due to a ring topology existing in the communication path, or an RSTP (rapid STP) improved therefrom. : Rapid STP / IEEE 802.1w) and other network control functions can be used to easily make the system redundant. It is also possible to relay-connect a plurality of ring wirings using a ring type switching hub (see, for example, Patent Documents 1 and 2).
On the other hand, in the star type, a star redundancy system can be configured by star-connecting each node to each of the two hubs, and the network bandwidth can be used efficiently.

Japanese Patent Laid-Open No. 10-200552 JP 2009-024734 A

  However, in such an Ethernet system, when a ring topology is used as a topology for connecting nodes that transmit and receive Ethernet communication frames, the transmission path is shared by the nodes, although it can be easily made redundant. Therefore, the network bandwidth that can be used by each node is limited. On the other hand, when the star topology is used, the network bandwidth can be used effectively, but the hardware such as communication cables and line concentrators increases due to redundancy, resulting in an increase in the cost of the entire system.

  Here, for example, in an Ethernet system used in a monitoring control system, a certain amount of bias occurs in the communication load at each node. For example, a node such as a server that performs monitoring operation frequently transmits and receives monitoring data, so the communication load is large. However, a node such as a terminal device that performs actual measurement and control intermittently transmits measurement and control data. The communication load is small because of transmission / reception.

  Therefore, in such an Ethernet system, by utilizing the characteristic of uneven communication load, nodes with small communication loads are connected by ring wiring to suppress an increase in hardware and for nodes with large communication loads. It is desirable to have a composite topology in which the network bandwidth is sufficiently secured by connecting with the star wiring, and the ring wiring and the wiring star wiring are relay-connected with the ring / star type switch.

FIG. 5 is a configuration example of a ring / star type Ethernet system. In the Ethernet system 5, two ring / star switches SW50 and SW60 are provided to relay-connect the ring wiring NWL and the star wiring NWS to each other.
In the ring wiring NWL, the ring side nodes N1 to N4 are connected in a ring shape by the wiring LP1 between the port PL12 of SW50 and the port PL22 of SW60, and between the port PL11 of SW50 and the port PL22 of SW60, The wirings LP0 are connected in a ring shape.

  On the other hand, in the star wiring NWS, the star side nodes G1 to G3 are star-connected to the switching hub HUB1 through the wiring LS10, and are also star-connected to the switching hub HUB2 through the wiring LS20. The port P11 of HUB1 is connected to the port PS11 of SW50 via the line LS1, and the port P21 of HUB2 is connected to the port PS21 of SW60 via the line LS2. Further, the port P12 of HUB1 is connected to the port PS22 of SW60 via the line LS3, and the port P22 of HUB2 is connected to the port PS12 of SW50 via the line LS4.

  SW50 and SW60 have a redundant configuration, such as an internal operation monitoring frame (IHCF: Internal Health Check Frame), an extended BPDU frame (BPDU_e: Bridge Protocol Data Unit external), power state signals POS1, POS2 (POS: Power ON Status), etc. Based on the above, if one is operating in the active system, the other operates as a standby system, and switches from the standby system to the active system in response to the occurrence of a partner failure.

  For example, when SW50 and SW60 are respectively in the active system and the standby system, the frame addressed to G2 transmitted from N3 is received by SW60 via N2 and N1 of LP1. Here, since SW60 is a standby system, this frame is transferred to SW50 via LP0. This frame is also transmitted from N3 via LP1 to the SW50 side in the opposite direction to N2, but since PL12 is blocked (B), it is transferred to N4 and discarded.

The SW 50 transfers the frame received from N3 from the PS11 and PS12 to the HUB1 and HUB2 via the LS1 and LS4. HUB1 receives the frame from SW50 at P11 and transmits it to G2 via LS10. Further, the HUB 2 receives the frame from the SW 50 at P 21 and transmits it to the G 2 via the LS 20.
Thereby, G2 receives a frame from both HUB1 and HUB2, takes one of them, and discards the other. A frame transmitted from G2 to N3 is transferred to N3 via a route reverse to the above.

  When a failure occurs in the SW 50, the SW 60 newly starts operating as an active system, receives a frame from N3, and transfers the frame from PS21 and PS22 to HUB1 and HUB2 via LS2 and LS3. As a result, the frame is transferred from HUB1, HUB2 to G2. A frame transmitted from G2 to N3 is transferred to N3 via a route reverse to the above.

Here, the general switching hub used as HUB1 and HUB2 temporarily holds the partner MAC address of the frame transmitted / received at the port for each port according to the transmission / reception of the frame at each port, When a frame addressed to the partner MAC address is received, it has a function of selecting and transmitting a port corresponding to the partner MAC address.
For this reason, the correspondence relationship between P11, P22 and the MAC address of N3 held before the failure of SW50 is the same even after a failure occurs in SW50 and the frame from N3 is not received by P11, P22. It is held for a certain holding time.

  Therefore, even if the SW 60 is switched to the active system after a failure occurs, the stored content indicating the correspondence with the port is cleared after a certain holding time elapses after the frame of the partner MAC address is not transmitted / received. In the meantime, the frame transmitted from G2 is transmitted from P11, P22 to SW50 in HUB1 and HUB2, and does not reach SW60. For this reason, there has been a problem that communication cannot be resumed immediately when operation is switched in response to the occurrence of a failure.

  The present invention is to solve such problems. When a failure occurs in one ring / star switch that relay-connects the ring wiring and the star wiring, the other ring / star switch communicates immediately. An object of the present invention is to provide a transfer control technique for a ring / star Ethernet system that can be resumed.

  In order to achieve such an object, the ring / star type Ethernet system according to the present invention includes first and second redundant configurations that are respectively ring-connected to a plurality of ring-side nodes that transmit and receive Ethernet communication frames. The first ring / star switch, the first ring / star switch, the first hub star-connected to a plurality of star-side nodes that transmit and receive Ethernet communication frames, and the second In addition to being connected to a ring / star type switch, the star side node and a second hub connected to the star are provided, and when the first ring / star type switch is operating as an active system, The frame is forwarded between the ring side node and the first hub, and the first half of the frame is transferred. When the device is operating as a standby system, the frame received from the second ring / star switch is copied to the first ring / star switch. The second ring / star switch transfers the frame between the ring side node and the second hub when the own device is operating as an active system. When a frame to be transferred to the second hub is duplicated and transferred to the first ring / star switch, and the device is operating as a standby system, the first ring / star The frame received from the type switch is transferred to the second hub.

  The ring / star switch according to the present invention includes a redundant first and second ring / star switches each having a ring connection with a plurality of ring-side nodes that transmit and receive Ethernet communication frames; Connected to the first ring / star switch, connected to the star-connected first hub and the second ring / star switch for transmitting / receiving Ethernet communication frames, and the second ring / star switch A first (second) ring / star type switch used in a ring / star type Ethernet system, comprising a star side node and a second star-connected hub, wherein the ring side node is ring-connected. A ring connection control circuit for transmitting and receiving frames to and from the ring side node, and the first (second) hub A star connection control circuit that connects and transmits / receives a frame, and connects to the second (first) ring / star switch to transmit / receive a frame, and between the ring connection control circuit and the star connection control circuit A switch circuit for relaying and forwarding the frame, and the star connection control circuit is connected between the ring side node and the first (second) hub when the device is operating as an active system. A frame to be transferred to the first (second) hub of the frame and transferred to the second (first) ring / star switch. In this case, the frame received from the second (first) ring / star switch is transferred to the first (second) hub.

  In addition, the frame transfer control method according to the present invention includes first and second ring / star switches in a redundant configuration that are ring-connected to a plurality of ring-side nodes that transmit and receive Ethernet communication frames, and Ethernet communication. A frame transfer control method used in a ring / star Ethernet system including a plurality of star-side nodes that transmit and receive a frame for transmission and first and second hubs that are star-connected, wherein the first ring / When the star switch is operating as an active system, the star switch transfers a frame between the ring side node and the first hub, and transfers the frame to the first hub. Duplicate the frame to be transferred to the second ring / star switch, and the own device is operating as a standby system. A step of transferring a frame received from the second ring / star switch to the first hub, and when the second ring / star switch is operating as an active system, A frame is transferred between the ring side node and the second hub, and a frame transferred to the second hub is duplicated and transferred to the first ring / star switch. And when the own apparatus is operating as a standby system, a step of transferring a frame received from the first ring / star switch to the second hub.

  Another frame transfer control method according to the present invention includes a first and second ring / star switches in a redundant configuration that are respectively ring-connected to a plurality of ring-side nodes that transmit and receive Ethernet communication frames, Connected to the first ring / star switch, and connected to a plurality of star-side nodes that transmit / receive Ethernet communication frames, a first hub that is star-connected, and the second ring / star switch. And a frame transfer control method used in a first (second) ring / star type switch used in a ring / star type Ethernet system comprising the star side node and a second hub connected in a star connection, When the own device is operating as an active system, the ring side node and the first (second) hub mutually Transferring the frame, copying the frame to be transferred to the first (second) hub among the frames and transferring the frame to the second (first) ring / star switch; When operating as a system, the method includes a step of transferring a frame received from the second (first) ring / star switch to the first (second) hub.

According to the present invention, not only a hub that transfers a frame received from a working ring / star switch to a star side node but also a frame received from a standby ring / star switch in a normal state, the star side node Also in the hub that forwards to, based on the frame forwarded to the star side node, the correspondence between the reception of the frame and the counterpart MAC address of the frame is maintained.
For this reason, when a failure occurs in the ring / star switch, in any of the two hubs, a frame transmitted from the star side node to the ring side node is sent to a legitimate MAC address corresponding to the frame's counterpart MAC address. It will be sent from the port. For this reason, when a failure occurs in one ring / star switch that relay-connects the ring wiring and the star wiring, communication can be immediately resumed by the other ring / star switch.

It is a block diagram which shows the structure of the ring / star type | mold Ethernet system concerning this invention. It is a structural example of a ring / star type switch. It is explanatory drawing which shows operation | movement (at the time of normal) of the ring / star type | mold Ethernet system concerning this invention. It is explanatory drawing which shows operation | movement (at the time of a failure occurrence) of the ring / star type | mold Ethernet system concerning this invention. It is a structural example of a ring / star type Ethernet system.

Next, an embodiment of the present invention will be described with reference to the drawings.
[Ring / Star Ethernet System]
First, a ring / star type Ethernet system 1 according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram showing a configuration of a ring / star type Ethernet system according to the present invention.

  This ring / star type Ethernet system 1 includes a ring wiring NWL for ring-connecting a plurality of ring-side nodes N1 to N4 that transmit and receive Ethernet communication frames, and a plurality of star-side nodes G1 and G1 that transmit and receive Ethernet communication frames. It has a function of redundantly relay-connecting the star wiring NWS for star-connecting G3.

  The ring / star type Ethernet system 1 includes, as main components, a ring / star type switch (first switch) having a redundant configuration in which each ring side node N1 to N4 is ring-connected via the ring wiring NWL. Ring / star type switch) SW10 and ring / star type switch (second ring / star type switch) SW20 are connected to the respective star side nodes G1 to G3 and the star wiring NWS, and are connected to a switching hub (first switch). 1 hub) HUB1 and a switching hub (second hub) HUB2.

  The SWs 10 and 20 operate redundantly in cooperation with each other, and have a function of relay-connecting each of the ring side nodes N1 to N4 and the switching hubs HUB1 and HUB2, respectively. Among these, SW10 is provided with two ports PL11 and PL12 on the ring wiring NWL side, and two ports PS11 and PS12 on the star wiring NWS side. The SW 20 has two ports PL21 and PL22 on the ring wiring NWL side, and two ports PS21 and PS22 on the star wiring NWS side.

  The ring-side nodes N1 to N4 are ring-connected between PL12 of SW10 and PL22 of SW20 via wiring LP1, and ring-connected between PL11 of SW10 and PL21 of SW20 by wiring LP0. .

HUB1 is provided with one port P11 on the SW10 side, and port PS11 of SW10 is connected to P11 of HUB1 via wiring LS1. The HUB2 is provided with one port P21 on the SW20 side, and the port PS21 of the SW20 is connected to the P21 of the HUB2 via the wiring LS2. These HUB1 and HUB2 are general concentrators represented by a switching hub.
Further, PS12 of SW10 is connected to PS22 of SW20 via wiring LS0.

The SW 10 is provided with a ring connection control circuit 11, a star connection control circuit 12, and a switch circuit 13 as main circuit portions.
Among these, the ring connection control circuit 11 is ring-connected to the wirings LP0 and LP1 via the ports PL11 and PL12, and is connected to the switch circuit 13.
The star connection control circuit 12 is connected to the lines LS1 and LS0 through the ports PS11 and PS12, and is connected to the switch circuit 13.

  The ring connection control circuit 11 has a function of transferring frames exchanged between the ring side nodes N1 to N4 between the ports PL11 and PL12, and the star side node G1 from the ring side nodes N1 to N4 received by the ports PL11 and PL12. To relay the frame addressed to G3 to the star connection control circuit 12 via the switch circuit 13, and the frame addressed from the star side nodes G1 to G3 to the ring side nodes N1 to N4 via the switch circuit 13. It has a function of receiving from the connection control circuit 12 and relaying and transferring from the ports PL11 and PL12 to the wirings LP0 and LP1.

  The star connection control circuit 12 receives frames addressed from the ring-side nodes N1 to N4 to the star-side nodes G1 to G3 from the ring connection control circuit 11 via the switch circuit 13, and from both the ports PS11 and PS12, the lines LS1, The same frame addressed to the ring side nodes N1 to N4 from the star side nodes G1 to G3, received from both the ports PS11 and PS12, when the function of relay forwarding to LS0 and the own apparatus are operating as the active system One of these is taken in, the other is discarded, and the relay connection is transferred to the ring connection control circuit 11 via the switch circuit 13.

  Further, the star connection control circuit 12 has a function of relaying and forwarding a frame received at the port PS12 from the port PS11 to the wiring LS1 and a frame received at the port PS11 when the device is operating as a standby system. , And a function of relay transfer from the port PS12 to the wiring LS0.

The SW 20 is provided with a ring connection control circuit 21, a star connection control circuit 22, and a switch circuit 23 as main circuit portions.
Among these, the ring connection control circuit 21 is ring-connected to the wirings LP0 and LP1 via the ports PL21 and PL22, and is connected to the switch circuit 23.
The star connection control circuit 22 is connected to the wirings LS2 and LS0 via the ports PS21 and PS22, respectively, and is connected to the switch circuit 23.

  The ring connection control circuit 21 has a function of transferring frames exchanged between the ring side nodes N1 to N4 between the ports PL21 and PL22, and the star side node G1 from the ring side nodes N1 to N4 received by the ports PL21 and PL22. To relay the frame addressed to G3 to the star connection control circuit 22 via the switch circuit 23, and the frame addressed from the star side nodes G1 to G3 to the ring side nodes N1 to N4 via the switch circuit 23. It has a function of receiving from the connection control circuit 22 and relaying and transferring from the ports PL21 and PL22 to the wirings LP0 and LP1.

  The star connection control circuit 22 receives frames addressed from the ring-side nodes N1 to N4 to the star-side nodes G1 to G3 from the ring connection control circuit 21 via the switch circuit 23, and from both the ports PS21 and PS22, the lines LS2, The same frame addressed to the ring side nodes N1 to N4 from the star side nodes G1 to G3, received from both the ports PS21 and PS22, when the function of relay forwarding to LS0 and the own apparatus are operating as the active system One of the above is taken in, the other is discarded, and the relay connection is transferred to the ring connection control circuit 21 via the switch circuit 23.

  Further, the star connection control circuit 22 has a function of relaying and forwarding a frame received at the port PS22 from the port PS21 to the wiring LS2 and a frame received at the port PS21 when the device is operating as a standby system. And a function of relay transfer from the port PS22 to the wiring LS0.

Here, with reference to FIG. 2, the structure of the ring connection control circuit 11 and the star connection control circuit 12 which comprise SW10 is demonstrated in detail. FIG. 2 is a configuration example of a ring / star type switch.
The ring connection control circuit 11 includes an electronic circuit formed on a semiconductor chip, and is provided with MAC processing units 11A, 11B, and 11D, a transfer processing unit 11C, and an RSTP processing unit 11E as main processing units.

  The MAC processing unit 11A connects to one end of the wiring LP0 via the port PL11, transfers the data frame received from the wiring LP0 to the transfer processing unit 11C, and transmits the data frame received from the transfer processing unit 11C to the wiring LP0. And a function of transferring the control frame received from the line LP0 to the RSTP processing unit 11E and transmitting the control frame received from the RSTP processing unit 11E to the line LP0.

  The MAC processing unit 11B is connected to one end of the wiring LP1 via the port PL12, transfers the data frame received from the wiring LP1 to the transfer processing unit 11C, and transmits the data frame received from the transfer processing unit 11C to the wiring LP1. And a function of transferring the control frame received from the line LP1 to the RSTP processing unit 11E and transmitting the control frame received from the RSTP processing unit 11E to the line LP1.

  The RSTP processing unit 11E is connected to each of the MAC processing units 11A and 11B, and monitors the operation state of the own device based on an internal operation monitoring frame (IHCF) exchanged with the MAC processing unit 11D. And a function for monitoring the operation state of SW20 based on an extended BPDU frame (BPDU_e: Bridge Protocol Data Unit external) exchanged with SW20, and a power supply of SW20 based on a power supply status signal POS2 signal (POS: Power ON Status) And a function of monitoring the state.

Furthermore, the RSTP processing unit 11E exchanges control frames between the function for controlling the operation mode of the own device and the ring-side nodes N1 to N4 of the wiring LP1 based on these monitoring results, thereby Based on (Rapid Spanning Tree Protocol), it has a function of performing redundancy control processing on the wirings LP0 and LP1.
As the redundancy control process, there are a process for setting the line LP1, a process for switching to a backup communication path by releasing blocking in response to the occurrence of a failure in the line LP1, and a process for resetting the line LP1 due to failure recovery.

As the operation mode, there are an active (ACTIVE) mode indicating a state of operating in the active system and a backup (BACKUP) mode indicating a state of operating as the standby system. In addition, there are an initial (INITIAL) mode indicating a state during initialization processing executed immediately after power-on or immediately after a failure recovery, and a failure (FAILURE) mode indicating a state when a failure occurs.
In addition, what is necessary is just to utilize well-known techniques, such as cited documents 1 and 2, about these monitoring functions and redundancy control processing in RSTP processing part 11E.

  The MAC processing unit 11D has a function of transmitting / receiving various frames such as a data frame and a control frame to / from the switch circuit 13, a function of transmitting / receiving an internal operation monitoring frame to / from the RSTP processing unit 11E, and an RSTP. When the internal operation monitoring frame transmitted by the processing unit 11E is received, the internal operation monitoring frame is transferred to the switch circuit 13 regardless of the data frame transfer control state for the switch circuit 13.

  The transfer processing unit 11C has a function of transferring the data frame output from the MAC processing units 11A, 11B, and 11D to any one of the MAC processing units 11A, 11B, and 11D based on destination information included in the data frame. And a function for controlling the restriction on the exchange of data frames with the MAC processing unit 11D based on the operation mode of the own device set by the RSTP processing unit 11E and held in the storage unit (not shown). ing.

  The star connection control circuit 12 includes an electronic circuit formed on a semiconductor chip. The main processing units include a MAC processing unit 12A, 12B, 12E, a transmission processing unit 12C, a reception processing unit 12D, an RSTP processing unit 12E, and a transfer. A processing unit 12G is provided.

The MAC processing unit 12A is connected to one end of the wiring LS1 via the port PS11, transfers a frame received from the wiring LS1 to the reception processing unit 12D, and receives a frame received from the transmission processing unit 12C and the transfer processing unit 12G. And a function of transmitting to the wiring LS1.
The MAC processing unit 12B is connected to one end of the wiring LS0 via the port PS12, and transfers the frame received from the wiring LS0 to the reception processing unit 12D, and the frame received from the transmission processing unit 12C and the transfer processing unit 12G. And a function of transmitting to the wiring LS0.

The transmission processing unit 12C has a function of copying the frame received from the MAC processing unit 12E into two and transferring it to both the MAC processing units 12A and 12B.
The reception processing unit 12D monitors the frames received from the MAC processing units 12A and 12B, and forwards the previously received frame to the MAC processing unit 22E. And a function of discarding.

  The RSTP processing unit 12F is connected to the MAC processing unit 12E and exchanges between the SW 20 and a function for monitoring the operation state of the own apparatus based on an internal operation monitoring frame (IHCF) exchanged with the MAC processing unit 12E. A function for monitoring the operating state of the SW 20 based on the extended BPDU frame (BPDU_e) to be performed, a function for monitoring the power state of the SW 20 based on the power state signal POS2 signal, and for the wirings LS0, LS1, LS2 based on these monitoring results A function of performing redundancy control processing. This redundancy control process includes a frame transfer process in the transfer processing unit 12G. In addition, what is necessary is just to utilize well-known techniques, such as cited references 1 and 2, about these monitoring functions in RSTP process part 12F.

  The MAC processing unit 12E has a function of transferring the data frame received from the switch circuit 13 to the transmission processing unit 12C, a function of transferring the data frame received from the reception processing unit 12D to the switch circuit 13, and the switch circuit 13 and the RSTP process. A function of exchanging control frames with the unit 12F, and a function of transmitting and receiving internal operation monitoring frames exchanged with the RSTP processing unit 12F.

  The transfer processing unit 12G is connected to the MAC processing units 12A and 12B, and does not operate when the own device is operating as an active system based on the monitoring result of the RSTP processing unit 12F, and the own device is a standby system. Are transferred from the MCA processing unit 12A to the wiring LS0, and a frame transmission from the MAC processing unit 12A to the wiring LS1 is transferred from the MCA processing unit 12B. It has a function.

The configurations of the ring connection control circuit 21 and the star connection control circuit 22 constituting the SW 20 are the same as the configurations of the ring connection control circuit 11 and the star connection control circuit 12 constituting the SW 10.
That is, in the ring connection control circuit 21, the MAC processing units 21A, 21B, and 21D, the transfer processing unit 21C, the RSTP processing unit 21E, and the ports PL21 and PL22 are connected to the MAC processing units 11A, 11B, and 11D in the ring connection control circuit 11. , Transfer processing unit 11C, RSTP processing unit 11E, and ports PL11 and PL12.

In the star connection control circuit 22, the MAC processing units 22A, 22B, and 22E, the transmission processing unit 22C, the reception processing unit 22D, the RSTP processing unit 22F, the transfer processing unit 22G, and the ports PS21 and PS22 are connected to the ring connection control circuit 11. Respectively correspond to the MAC processing units 12A, 12B, and 12E, the transmission processing unit 12C, the reception processing unit 12D, the RSTP processing unit 12F, the transfer processing unit 12G, and the ports PS11 and PS12.
Therefore, the detailed description about the structure of the ring connection control circuit 21 and the star connection control circuit 22 which comprise SW20 is abbreviate | omitted.

[Operation of this embodiment]
Next, the operation of the ring / star Ethernet system 1 according to the present embodiment will be described with reference to FIGS. FIG. 3 is an explanatory diagram showing the operation (normal) of the ring / star Ethernet system according to the present invention. FIG. 4 is an explanatory diagram showing the operation (when a failure occurs) of the ring / star Ethernet system according to the present invention.

  First, referring to FIG. 3, as an operation at normal time in the ring / star Ethernet system 1, a case where a frame is exchanged between the ring side node N3 and the star side node G2 will be described as an example. Here, it is assumed that SW10 is operating as an active system and SW20 is operating as a standby system.

  A frame addressed to G2 transmitted from N3 is received by SW20 via N2 and N1 of LP1, and transferred to SW10 via LP0 by ring connection control circuit 21. This frame is also transmitted from N3 via LP1 to the SW10 side opposite to N2, but PL12 is blocked (B) by SW10, so it is discarded after being transferred to N4.

  The SW 10 receives the frame from N 3 at the PL 11 and transfers it from the ring connection control circuit 11 to the star connection control circuit 12 via the switch circuit 13. Here, the star connection control circuit 12 transfers the received frame from both PS11 and PS12 to the lines LS1 and LS0, respectively, because the own device is operating as an active system.

HUB1 receives the frame from SW10 at P11 and transmits it to G2 via wiring LS10.
On the other hand, SW20 receives the frame from SW10 at PS22. Here, the star connection control circuit 22 transfers the received frame from the PS 21 to the wiring LS2 because the device itself operates as a standby system.

HUB2 receives the frame from SW20 at P21 and transmits it to G2 via wiring LS20.
Thereby, G2 receives a frame from both HUB1 and HUB2, takes one of them, and discards the other.

A frame transmitted from G2 to N3 is transmitted to both HUB1 and HUB2 via LS10 and LS20.
The HUB 1 transmits the frame received from the LS 10 to the LS 1 from P 11 corresponding to the partner MAC address of the frame. Similarly, HUB2 transmits the frame received from LS20 from P21 corresponding to the counterpart MAC address of the frame to LS2. In these HUB1 and HUB2, the correspondence relationship between the port and the partner MAC address of the frame is saved when a frame is received from the port.

SW20 receives the frame from HUB2 at PS21. Here, the star connection control circuit 22 transfers the received frame from the PS 22 to the wiring LS0 because the device itself operates as a standby system.
The SW 10 receives both the frame from the HUB 1 at PS 11 and the frame from the SW 20 at PS 12 by the star connection control circuit 12, captures one of them, discards the other, and passes the captured frame via the switch circuit 13. To the ring connection control circuit 11, and since PL12 is blocked (B), it transmits from PL11.

  Further, the SW 20 receives the frame from the SW 10 at the PL 21 and transfers it to the PL 22 by the ring connection control circuit 21. As a result, this frame is received at N3 via N1 and N2 of LP1.

  Next, with reference to FIG. 4, as an operation when a failure occurs in the ring / star Ethernet system 1, a case where a frame is exchanged between the ring side node N3 and the star side node G2 will be described as an example. Here, it is assumed that a failure has occurred in SW10 and SW20 is operating by switching from the standby system to the active system.

A frame addressed to G2 transmitted from N3 is received by SW20 via N2 and N1 of LP1, and transferred from ring connection control circuit 21 to star connection control circuit 22 via switch circuit 23. Since PL21 is blocked (B) by SW20, it is not transferred from PL21.
Here, the star connection control circuit 22 transfers the received frame from both PS21 and PS22 to the wirings LS2 and LS0, respectively, because the own device operates as an active system.

HUB2 receives the frame from SW20 at P21 and transmits it to G2 via wiring LS20.
A frame transmitted from G2 to N3 is transmitted to both HUB1 and HUB2 via LS10 and LS20.
The HUB 1 transmits the frame received from the LS 10 to the LS 1 from P 11 corresponding to the partner MAC address of the frame. Similarly, HUB2 transmits the frame received from LS20 from P21 corresponding to the counterpart MAC address of the frame to LS2.

  In these HUB1 and HUB2, the correspondence relationship between the port and the partner MAC address of the frame is saved when a frame is received from the port. Here, since the frame transferred from SW10 to HUB1 in the normal state described with reference to FIG. 3 was also transferred to HUB2 via SW10 through SW20, P21 corresponds to the port corresponding to the MAC address of N3 in HUB2. It is attached.

Therefore, even if a failure occurs in SW10, a frame addressed from G2 to N3 is reliably transferred in HUB2 from P21 corresponding to the other party's MAC address of the frame to SW20 that has newly started operation as the active system. Will be.
Therefore, SW20 receives the frame from HUB2 at PS21, transfers it to ring connection control circuit 21 via star connection control circuit 22 and switch circuit 23, and transmits from PL22 because PL21 is blocked (B). To do. As a result, this frame is received at N3 via N1 and N2 of LP1.

[Effects of the present embodiment]
As described above, in the present embodiment, when the ring / star switch (first ring / star switch) SW10 is operating as the active system, the switch / hub (first hub) HUB1 is used. The frame to be transferred is duplicated and transferred to the ring / star switch (second ring / star switch) SW20. When the own apparatus is operating as a standby system, the frame received from SW20 is transferred to HUB1, When the own device is operating as the active system, the SW 20 duplicates the frame to be transferred to the switching hub (second hub) HUB 2 and transfers it to the SW 10. When the own device is operating as the standby system, the SW 10 The frame received from is transferred to HUB2.

  Therefore, in a normal state, not only the switching hub HUB1 that transfers the frame received from the active ring / star switch SW10 to the star side nodes G1 to G3, but also the frame received from the standby ring / star switch SW20. Also in the switching hub HUB2 that transfers to the star side nodes G1 to G3, based on the frame transferred to the star side nodes G1 to G3, the correspondence relationship between the ports P11 and P21 that received the frame and the counterpart MAC address of the frame is Retained.

  For this reason, when a failure occurs, in both HUB1 and HUB2, a frame transmitted from G1 to G3 to N1 to N4 is transmitted from a regular port corresponding to the counterpart MAC address of the frame. Become. For this reason, when a failure occurs in one SW 10 (20) that relay-connects the ring wiring NWL and the star wiring NWS, communication can be resumed immediately in the other SW 20 (10).

[Extended embodiment]
The present invention has been described above with reference to the embodiments, but the present invention is not limited to the above embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Ring / star type Ethernet system, SW10 ... Ring / star type switch (first ring / star type switch), 11 ... Ring connection control circuit, 12 ... Star connection control circuit, 11A, 11B, 11D, 12A, 12B , 12E ... MAC processing unit, 11C, 12G ... transfer processing unit, 11E, 12F ... RSTP processing unit, 12C ... transmission processing unit, 12D ... reception processing unit, 13 ... switch circuit, SW20 ... ring / star type switch (second) Ring / star type switch), 21 ... ring connection control circuit, 22 ... star connection control circuit, 21A, 21B, 21D, 22A, 22B, 22E ... MAC processing unit, 21C, 22G ... transfer processing unit, 21E, 22F ... RSTP processing unit, 22C ... transmission processing unit, 22D ... reception processing unit, 23 ... switch circuit, HUB1 ... switch Hub (first hub), HUB2 ... switching hub (second hub), N1, N2, N3, N4 ... ring side node, G1, G2, G3 ... star side node, NWL ... ring wiring, LP0, LP1 ... Wiring, NWS ... Star wiring, LS0, LS1, LS2, LS10, LS20 ... Wiring.

Claims (4)

Redundant first and second ring / star switches, each ring-connected to a plurality of ring-side nodes that transmit and receive Ethernet communication frames;
A first hub that is connected to the first ring / star switch and is star-connected to a plurality of star-side nodes that transmit and receive a frame for Ethernet communication;
A second hub connected to the second ring / star switch and star-connected to the star side node;
When the first ring / star switch operates as an active system, the first ring / star switch transfers a frame between the ring side node and the first hub, and among the frames, When a frame to be transferred to the first hub is duplicated and transferred to the second ring / star switch, and the device is operating as a standby system, the frame received from the second ring / star switch To the first hub,
When the second ring / star switch is operating as an active system, the second ring / star switch transfers a frame between the ring side node and the second hub, and the second ring / star switch When the frame to be transferred to the second hub is duplicated and transferred to the first ring / star switch, and the device is operating as a standby system, the frame received from the first ring / star switch Is transferred to the second hub. A ring / star Ethernet system, wherein: A redundant configuration of the first and second ring / star type switches connected to a plurality of ring-side nodes that transmit and receive Ethernet communication frames, and the first ring / star type switch, and the first ring / star type switch, A plurality of star-side nodes that transmit and receive a frame for Ethernet communication are connected to the first hub that is star-connected, the second ring / star-type switch, and a second star-connected to the star-side node A first (second) ring / star switch used in a ring / star Ethernet system comprising a hub,
A ring connection control circuit that makes a ring connection with the ring side node and transmits / receives a frame to / from the ring side node;
A star connection control circuit connected to the first (second) hub for transmitting and receiving frames and connected to the second (first) ring / star switch to transmit and receive frames;
A switch circuit that relays and forwards a frame between the ring connection control circuit and the star connection control circuit;
The star connection control circuit transfers a frame between the ring side node and the first (second) hub when the own apparatus is operating as an active system, and the star connection control circuit When the frame to be transferred to the first (second) hub is duplicated and transferred to the second (first) ring / star switch, and the device is operating as a standby system, the second (first) A ring / star type switch characterized by transferring a frame received from the ring / star type switch of 1) to the first (second) hub. Redundant first and second ring / star switches each ring-connected to a plurality of ring-side nodes that transmit and receive Ethernet communication frames, and a plurality of star-side nodes that transmit and receive Ethernet communication frames A frame transfer control method used in a ring / star type Ethernet system including first and second hubs connected in a star connection,
When the first ring / star switch operates as an active system, the first ring / star switch transfers a frame between the ring side node and the first hub, and among the frames, When a frame to be transferred to the first hub is duplicated and transferred to the second ring / star switch, and the device is operating as a standby system, the frame received from the second ring / star switch Transferring to the first hub;
When the second ring / star switch operates as an active system, the second ring / star switch transfers a frame between the ring side node and the second hub, and among the frames, When the frame to be transferred to the second hub is duplicated and transferred to the first ring / star switch, and the device is operating as a standby system, the frame received from the first ring / star switch Transferring to the second hub. A frame transfer control method comprising: A redundant configuration of the first and second ring / star type switches connected to a plurality of ring-side nodes that transmit and receive Ethernet communication frames, and the first ring / star type switch, and the first ring / star type switch, A plurality of star-side nodes that transmit and receive a frame for Ethernet communication are connected to the first hub that is star-connected, the second ring / star-type switch, and a second star-connected to the star-side node A frame transfer control method used in a first (second) ring / star switch used in a ring / star Ethernet system comprising a hub,
When the own apparatus is operating as an active system, the frame is transferred between the ring side node and the first (second) hub, and the first (second) of the frames is transferred. Duplicating a frame to be transferred to the hub and transferring it to the second (first) ring / star switch;
Transferring the frame received from the second (first) ring / star switch to the first (second) hub when the own device is operating as a standby system, Frame transfer control method.

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