JP2011188414A - Ring type switch, ring type ethernet system, method of controlling ring type switch, and method of controlling ring type ethernet system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable a monitoring frame to be exchanged even when data frame transfer is stopped by the lack of free capacity in a receiving buffer in a ring type switch. <P>SOLUTION: When a frame is received from a ring connection control circuit 11B through a switching portion 12, a ring connection control circuit 11A controls the output of a data frame transfer stop signal through a control signal line 14 in accordance with whether or not the free capacity of its own receiving buffer for receiving the frame is sufficient. The ring connection control circuit 11B controls transfer of a data frame to the switching portion 12 in accordance with whether or not the data frame transfer stop signal through the control signal line 14 is detected. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a ring-type Ethernet (registered trademark) communication technique, and more particularly to a control technique for a ring-type switch that connects a plurality of ring-type Ethernets.

In a monitoring control system that monitors and controls building facilities and plant facilities, communication devices having various functions such as information collection functions and control functions are connected as nodes via a communication network, and a central monitoring device is used based on information from these nodes. It monitors and controls individual equipment. In such a supervisory control system, a ring type Ethernet that connects nodes by a crossover wiring system is used as a communication network.
This ring Ethernet has an STP (Spanning Tree Protocol / IEEE 802.1D) function that avoids communication errors due to ring topology existing in the communication path, and an improved RSTP (Rapid STP: Rapid STP). System redundancy can be realized using network control functions such as (IEEE 802.1w) function.

Here, when a large-scale Ethernet used in a building facility, a plant facility, or the like is realized by a single ring, all nodes share one ring, so that the reliability of the system is lowered.
As a technique for solving such a problem, a method has been proposed in which each node is divided and connected to a plurality of sub-rings, and these sub-rings are interconnected using a general switching unit (for example, a patent). Reference 1 etc.). Thereby, since the risk is distributed to each sub-ring, the reliability of the system is improved.

JP 2006-174422 A

In such a conventional technology, when a failure occurs in a certain subring, not only is a new communication route reconstructed in the failure occurrence subring, but also a new communication route in a subring other than the failure occurrence subring. Therefore, Ethernet communication between nodes connected to a normal sub-ring is temporarily hindered.
For this reason, as a related technique related to the prior art, when a MAC frame including control information for redundancy control processing is received from a sub ring in a ring connection control circuit, the MAC frame is transferred to another sub ring. A method of regulating the output can be considered.

  FIG. 11 is a configuration example of a ring Ethernet having a ring switch according to the related art. In the ring type switch 60, ring connection control circuits 61 A and 61 B provided corresponding to the two sub-rings 51 and 52 are connected via the switching unit 62.

In the ring connection control circuits 61A and 61B, when a MAC frame including control information for redundancy control processing related to the sub rings 51 and 52 is received from a port at one end of the sub rings 51 and 52, a switching unit is applied to the MAC frame. While restricting the output to 62, the MAC frame is output to the ports at the other ends of the sub-rings 51 and 52.
Thereby, the influence of the redundancy control processing in the sub-rings 51 and 52 can be suppressed with respect to other sub-rings connected via the switching unit 62. For this reason, even when a failure occurs in an arbitrary subring, Ethernet communication in a normal subring can be maintained.

  In such a related technique, for example, when a data frame is transferred from the sub-ring 51 to the sub-ring 52, if for some reason the free capacity of the reception buffer of the ring connection control circuit 61B is insufficient, the ring connection control circuit A PAUSE frame for instructing the transfer stop of the data frame is transmitted from 61B to the switching unit 62. Thereby, the switching unit 62 stops the data frame transfer to the ring connection control circuit 61B.

  Here, the switching unit 62 continues to receive the data frame transferred from the ring connection control circuit 61A until the free capacity of its own reception buffer is insufficient, and when the free capacity of its own reception buffer is insufficient, A PAUSE frame is transmitted from the switching unit 62 to the connection control circuit 61A. Thereby, the ring connection control circuit 61A stops the data frame transfer to the switching unit 62.

On the other hand, the ring connection control circuits 61A and 61B monitor the switching unit 62 with a monitoring frame such as an internal operation check frame (IHCF) in order to periodically monitor the state of the communication path in the redundancy control process. When a monitoring frame does not arrive for a certain period, it has a function to determine that a failure has occurred.
For this reason, when the communication of the ring connection control circuits 61A and 61B via the switching unit 62 is stopped according to the PAUSE frame, the monitoring frame is also stopped. However, the problem is that it is determined that a failure has occurred.

  The present invention is intended to solve such problems, and a ring type switch and a ring type Ethernet system capable of exchanging monitoring frames even when data frame transfer is stopped due to a lack of free space in a reception buffer in the ring type switch. And a communication control method.

  In order to achieve such an object, a ring switch according to the present invention is connected to a first sub-ring and a second sub-ring that connect a plurality of different nodes in a ring shape. A ring-type switch that relay-connects between the second sub-rings, the first ring connection control circuit connected to the first sub-ring, and the second ring connection control connected to the second sub-ring A circuit, a switching unit that relays and transfers various frames exchanged between the first and second ring connection control circuits, and a relay unit that is connected between the first and second ring connection control circuits and relayed and transferred by the switching unit. A control signal line for exchanging data frame transfer stop signals for instructing data frame transfer stop among the frames to be transmitted to each other, and a first (second) link When the connection control circuit receives a frame from the second (first) ring connection control circuit via the switching unit, according to the lack of free space in its own reception buffer for receiving the frame, A data frame transfer stop signal is output via the control signal line, and the second (first) ring connection control circuit receives data to the switching unit in response to detection of the data frame transfer stop signal via the control signal line. Frame transfer is stopped.

  The ring Ethernet system according to the present invention includes a first sub-ring that connects a plurality of nodes in a ring shape, and a second sub-ring that connects a plurality of nodes different from the nodes of the first sub-ring in a ring shape. And a ring connected to the first sub-ring and connected to the second sub-ring, the Ethernet between the first sub-ring and the second sub-ring. A first ring type switch that realizes Ethernet communication between the node connected to the first sub-ring and the node connected to the second sub-ring by relaying communication is provided.

  At this time, the ring-type switch described above is connected to the first sub-ring and is connected to the second sub-ring to perform Ethernet communication between the first sub-ring and the second sub-ring. The first ring further includes a second ring type switch that realizes Ethernet communication between the node connected to the first sub-ring and the node connected to the second sub-ring by relay connection. The type switch and the second ring type switch perform duplication control processing based on the operating state of the self and the other party exchanged with each other, so that one of them operates as the active system and the Ethernet between the first and second sub-rings. The communication may be relay-connected and the other may operate as a standby system to stop the relay connection between the first and second sub-rings.

  The ring-type switch control method according to the present invention is connected to a first sub-ring and a second sub-ring that connect a plurality of different nodes in a ring shape, and between these first and second sub-rings. A ring-type switch control method used in a ring-type switch for relay connection of a ring-type switch, wherein the ring-type switch is connected to a first ring connection control circuit connected to a first sub-ring and to a second sub-ring A second ring connection control circuit; a switching unit that relays and forwards various frames exchanged between the first and second ring connection control circuits; and a connection between the first and second ring connection control circuits, Control for exchanging data frame transfer stop signals to instruct transfer stop of data frame among frames relayed by switching unit And a first (second) ring connection control circuit for receiving the frame from the second (first) ring connection control circuit via the switching unit. A step of outputting a data frame transfer stop signal via a control signal line in response to a lack of free space in its own reception buffer, and a second (first) ring connection control circuit receiving data via the control signal line And a step of stopping the transfer of the data frame to the switching unit in response to the detection of the frame transfer stop signal.

  Also, the ring type Ethernet system control method according to the present invention provides a first sub-ring by relay-connecting between a first sub-ring and a second sub-ring that connect a plurality of different nodes in a ring shape. A ring type Ethernet system control method used in a ring type Ethernet system for realizing Ethernet communication between a node connected to the node and a node connected to a second sub-ring, wherein the ring type Ethernet system is claimed in claim 1. And a first ring-type switch connected to the second sub-ring, the first ring-type switch being connected to the first sub-ring, wherein the first ring-type switch is connected to the first sub-ring. Connected to the first sub-ring by relaying Ethernet communication between the ring and the second sub-ring And a over de steps to implement Ethernet communication between the nodes connected to the second sub-ring.

  In this case, the ring-type switch described above is connected to the first sub-ring and further includes a second ring-type switch connected to the second sub-ring. The ring-type switch performs duplex control processing based on the operating state of the self and the other party exchanged with each other, so that one of them operates as the active system and relays the Ethernet communication between the first and second sub-rings. At the same time, the other may operate as a standby system to stop the relay connection between the first and second sub-rings.

  According to the present invention, since the data frame transfer stop is directly exchanged between the ring connection control circuits not via the switching unit but via the control signal line, it is possible to avoid the frame transfer operation from stopping in the switching unit. For this reason, even if the reception buffer has insufficient free space, a monitoring frame such as an internal operation monitoring frame transmitted from one ring connection control circuit is transmitted to the other ring via the switching unit, as in the normal state. It reaches the connection control circuit. For this reason, even if data frame transfer is stopped due to a lack of free space in the reception buffer in the ring type switch, monitoring frames can be exchanged, and erroneous determination of failure occurring due to data frame transfer stop is suppressed. Is possible.

It is a block diagram which shows the structure of the ring type Ethernet system and ring type switch concerning 1st Embodiment. It is a block diagram which shows the structure of the ring type switch concerning 1st Embodiment. It is a flowchart which shows the frame transmission control process concerning 1st Embodiment. It is a flowchart which shows the frame reception control processing concerning 1st Embodiment. It is a block diagram which shows the structure of the ring type Ethernet system and ring type switch concerning 2nd Embodiment. It is a block diagram which shows the structure of the ring connection control circuit concerning 2nd Embodiment. It is an example of a structure of the duplication control part of the ring type switch of a RSTP process part. It is a transition diagram which shows the operation mode of a ring type switch. It is a flowchart which shows the initialization process of a ring connection control circuit. It is a flowchart which shows the duplication control processing of a ring connection control circuit. It is a structural example of the ring type Ethernet with the ring type switch by related technology.

Next, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
First, a ring type Ethernet system and a ring type switch according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram illustrating a configuration of a ring Ethernet system and a ring switch according to the first embodiment.

  This ring Ethernet system 1 includes a sub-ring (first sub-ring) 51 that connects a plurality of nodes such as a route R and a node N in a ring shape, and a route R or node different from the node of the sub-ring 51. A sub-ring (second sub-ring) 52 that connects a plurality of nodes such as N in a ring shape is connected in series to the sub-ring 51, and is connected in series to the sub-ring 52. A ring switch 10 is provided that realizes Ethernet communication between a node connected to the sub-ring 51 and a node connected to the sub-ring 52 by relay-connecting the Ethernet communication with each other.

  In this embodiment, a ring connection control circuit (first ring connection control circuit) 11A connected in series to the sub-ring 51 and a ring connection control circuit (first connection) connected in series to the sub-ring 52 are connected to the ring switch 10. 2 ring connection control circuit) 11B, switching unit 12 for relay connection of Ethernet communications of these ring connection control circuits 11A, 11B, and data connected via ring connection control circuits 11A, 11B via switching unit 12 And a control signal line 14 for exchanging data frame transfer stop signals to instruct to stop frame transfer. The ring connection control circuit 11A (11B) connects the switching unit 12 from the ring connection control circuit 11B (11A). When receiving a data frame via, receive itself to receive the data frame The ring connection control circuit 11B (11A) stops the data frame transfer via the control signal line 14 by controlling the output of the data frame transfer stop signal via the control signal line 14 according to whether or not the free capacity of the buffer is insufficient. The data frame transfer to the ring connection control circuit 11B (11A) via the switching unit 12 is controlled according to the presence or absence of signal detection.

[Ring type switch]
Next, the configuration of the ring type switch according to the present embodiment will be described with reference to FIG. FIG. 2 is a block diagram illustrating a configuration of the ring type switch according to the first embodiment.
The ring type switch 10 is provided with ring connection control circuits 11A and 11B, a switching unit 12, a relay connection communication path 13, and control signal lines 14 (14A and 14B) as main components.

  The ring connection control circuit 11 </ b> A is connected in series to the sub-ring 51, functions to transfer various frames such as data frames and control frames exchanged between the nodes of the sub-ring 51, and from the node of the sub-ring 51 to the sub-ring A function of receiving various frames such as data frames and control frames transmitted to the node 52 from the sub-ring 51 and relaying them to the ring connection control circuit 11B via the switching unit 12; It has a function of receiving various frames such as data frames and control frames transmitted to the nodes of the ring 51 from the ring connection control circuit 11B via the switching unit 12 and relaying and transferring them to the sub-ring 51.

  In addition, when the ring connection control circuit 11A receives a data frame from the ring connection control circuit 11B via the switching unit 12, the lack of free space in its own reception buffer for receiving the data frame In response to the function of controlling the output of the data frame transfer stop signal via the control signal line 14 and the presence / absence of detection of the data frame transfer stop signal from the ring connection control circuit 11B via the control signal line 14, The function of controlling the transfer of the data frame to the ring connection control circuit 11B via the switching unit 12 and the switching unit when the monitoring frame for detecting the failure is received from the sub-ring 51 regardless of the transfer control state of the data frame 12 has a function of transferring a monitoring frame to 12.

  The ring connection control circuit 11B is connected in series to the sub-ring 52 and transfers various frames such as data frames and control frames exchanged between the nodes of the sub-ring 52, and the sub-ring from the node of the sub-ring 52. A function of receiving various frames such as data frames and control frames transmitted to the node 51 from the sub-ring 52 and relaying and transferring them to the ring connection control circuit 11A via the switching unit 12; It has a function of receiving various frames such as data frames and control frames transmitted to the nodes of the ring 52 from the ring connection control circuit 11A via the switching unit 12 and relaying and transferring them to the sub-ring 52.

  In addition, when the ring connection control circuit 11B receives a data frame from the ring connection control circuit 11A via the switching unit 12, the lack of free space in its own reception buffer for receiving the data frame In response to the function of controlling the output of the data frame transfer stop signal via the control signal line 14 and the presence / absence of detection of the data frame transfer stop signal from the ring connection control circuit 11A via the control signal line 14, When the function for controlling the transfer of the data frame to the ring connection control circuit 11A via the switching unit 12 and the monitoring frame for detecting the failure from the sub-ring 52 are received, the data frame transfer control state for the switching unit 12 is set. Regardless, it has a function of transferring a monitoring frame to the switching unit 12.

  The switching unit 12 includes a general switching unit that relay-connects the ring connection control circuit 11A and the ring connection control circuit 11B via the relay connection communication path 13, and outputs the ring connection control circuit 11A to the relay connection communication path 13. A function of receiving various frames such as a data frame and a control frame received by the own reception buffer and transferring them to the ring connection control circuit 11B via the relay connection communication path 13, and relay connection communication from the ring connection control circuit 11B. It has a function of receiving various frames such as data frames and control frames output to the path 13 by its own reception buffer and transferring them to the ring connection control circuit 11A via the relay connection communication path 13.

[Ring connection control circuit]
Next, the configuration of the ring connection control circuit used in the ring type switch according to the present embodiment will be described in detail with reference to FIG. FIG. 2 is a block diagram illustrating a configuration of the ring connection control circuit according to the first embodiment.

  The ring connection control circuits 11A and 11B are electronic circuits formed on a semiconductor chip, and connect the sub-rings 51 and 52 that connect a plurality of nodes (root node R and node N) in series in a ring shape to the ring type switch 10. Has a connection control function. The ring connection control circuits 11A and 11B have the same configuration, and here, the ring connection control circuit 11A will be described as an example.

  The ring connection control circuit 11A is provided with MAC processing units 21 and 22, an RSTP processing unit 23, a MAC processing unit 24, and a transfer processing unit 25 as main processing units.

  The MAC processing unit 21 is connected to one end of the sub-ring 51 via the ring connection port P2, transfers the data frame received from the node to the transfer processing unit 25, and receives the data frame received from the transfer processing unit 25. It has a function of transmitting to the node and a function of transmitting the control frame received from the node to the RSTP processing unit 23 and transmitting the control frame received from the RSTP processing unit 23 to the node.

  The MAC processing unit 22 is connected to the other end of the sub-ring 51 via the ring connection port P1, transfers the data frame received from the node to the transfer processing unit 25, and receives the data frame received from the transfer processing unit 25. As well as a function for transferring the control frame received from the node to the RSTP processing unit 23 and for transmitting the control frame received from the RSTP processing unit 23 to the node.

The RSTP processing unit 23 is connected to each of the MAC processing units 21 and 22, and exchanges control frames with each node of the sub-ring 51, thereby based on RSTP (Rapid Spanning Tree Protocol). It has a function of performing redundancy control processing for the sub-ring 51.
The redundancy control processing includes sub-ring 51 setting processing, switching processing to a backup communication path by releasing blocking according to occurrence of a failure in the sub-ring 51, sub-ring 51 re-setting processing due to failure recovery, and the like. is there.

  The MAC processing unit 24 is connected to the non-ring connection port P3 and transmits / receives various frames such as data frames and control frames to / from the switching unit 12 connected to the relay connection communication path 13. And an internal operation check frame (IHCF: Internal Health Check Frame) exchanged with the RSTP processing unit 23.

  In addition, the MAC processing unit 24 sends a data frame transfer stop signal (hereinafter referred to as a PAUSE signal) to the MAC processing unit 24 of the ring connection control circuit 11B to stop the data frame transfer via the switching unit. They are connected by control signal lines 14 (14A, 14B) for exchange. Among these, the control signal line 14A is a signal line for transmitting a PAUSE signal, and the control signal line 14B is a signal line for receiving a PAUSE signal.

  As a flow control function using such a PAUSE signal, the MAC processing unit 24, when receiving a data frame from the switching unit 12 via the relay connection communication path 13, has its own for receiving the data frame. A function for controlling the output of the PAUSE signal via the control signal line 14A according to whether or not the free space of the reception buffer is insufficient, and the switching unit 12 depending on whether or not the PAUSE signal is detected via the control signal line 14B. When the function for controlling the transfer of the data frame and the internal operation monitoring frame transmitted by the RSTP processing unit 23 are received, the internal operation monitoring frame is transferred to the switching unit 12 regardless of the data frame transfer control state for the switching unit 12. And a function to transfer to.

  The transfer processing unit 25 has a function of transferring the data frame output from the MAC processing units 21, 22, and 24 to any one of the MAC processing units 21, 22, and 24 based on destination information included in the data frame. And a function for controlling restrictions on data frame exchange with the MAC processing unit 24 based on its own operation mode set by the RSTP processing unit 23 and held in a storage unit (not shown). Yes.

[Operation of First Embodiment]
Next, the operation of the ring type switch according to the present embodiment will be described. Here, assuming a situation in which a data frame is transmitted from the node of the sub ring 52 to the node of the sub ring 51, the frame transmission control operation in the MAC processing unit 24 via the switching unit 12 in the ring connection control circuit 11B The frame reception control operation in the MAC processing unit 24 via the switching unit 12 in the ring connection control circuit 11A will be described. The frame transmission control operation and the frame reception control operation executed by the ring connection control circuits 11A and 11B have the same processing contents.

[Frame transmission control operation]
First, the frame transmission control operation according to the present embodiment will be described with reference to FIG. FIG. 3 is a flowchart illustrating a frame transmission control process according to the first embodiment.
The ring connection control circuit 11B of the ring type switch 10 is operated by the MAC processing unit 24 in parallel with the frame transmission operation for transmitting various frames such as data frames and control frames to the ring connection control circuit 11A via the switching unit 12. The frame transmission control process shown in FIG. 3 is executed.

First, the MAC processing unit 24 monitors the control signal line 14A to confirm whether or not the PAUSE signal is output from the ring connection control circuit 11A (step 100).
If no PAUSE signal is detected (step 100: NO), the MAC processing unit 24 transmits a data frame to be transmitted from the port P3 to the switching unit 12 via the relay connection communication path 13 in the frame transmission operation. Is permitted (step 101), and the process returns to step 100.

On the other hand, when the PAUSE signal is detected (step 100: YES), the MAC processing unit 24 stops the transmission of the data frame transmitted from the port P3 to the switching unit 12 via the relay connection communication path 13 in the frame transmission operation. (Step 102), the process returns to step 100.
Thereby, when the PAUSE signal is detected, the transmission of only the data frame is stopped in the frame transmission operation. Note that a frame other than a data frame, such as an internal operation monitoring frame, is transmitted by a frame transmission operation even when a PAUSE signal is detected.

[Frame reception control operation]
Next, the frame reception control operation according to this embodiment will be described with reference to FIG. FIG. 4 is a flowchart illustrating a frame reception control process according to the first embodiment.
The ring connection control circuit 11A of the ring switch 10 is operated by the MAC processing unit 24 in parallel with the frame reception operation for receiving various frames such as data frames and control frames from the ring connection control circuit 11B via the switching unit 12. The frame reception control process shown in FIG. 4 is executed.

  First, the MAC processing unit 24 checks the usage status of its own reception buffer (step 110). At this time, the reception buffer has a storage capacity with a margin for the maximum storage capacity as a threshold value, and the capacity depends on whether or not the reception buffer usage capacity has reached the threshold value. It is confirmed whether there is a shortage.

  If the free capacity of the reception buffer is not insufficient (step 110: NO), the MAC processing unit 24 stops outputting the PAUSE signal from the control signal line 14A to the MAC processing unit 24 of the ring connection control circuit 11B. (Step 111) and return to Step 110.

On the other hand, when the free capacity of the reception buffer is insufficient (step 110: YES), the MAC processing unit 24 outputs a PAUSE signal from the control signal line 14A to the MAC processing unit 24 of the ring connection control circuit 11B ( Step 112), and return to Step 110.
As a result, data frame transmission to the switching unit 12 is stopped in the MAC processing unit 24 of the ring connection control circuit 11B.

At this time, even when the PAUSE signal is output in a state where the free space of the reception buffer is insufficient, the frames of the reception buffer are sequentially read out and transferred by the MAC processing unit 24 unless a failure occurs. Transferred to the unit 25. For this reason, the used capacity of the reception buffer is gradually reduced.
Therefore, when the used capacity of the reception buffer falls below the threshold value and the lack of free space in the reception buffer is resolved (step 110: NO), the MAC processing unit 24 performs PAUSE for the MAC processing unit 24 of the ring connection control circuit 11B. The output of the signal is stopped (step 111), and an instruction to resume transmission of the data frame is given.

  Here, since the PAUSE signal is directly output to the MAC processing unit 24 of the ring connection control circuit 11B via the control signal line 14A, it is not output to the switching unit 12. For this reason, the suspension of the frame transfer operation in the switching unit 12 is avoided, and various frames transmitted from the MAC processing unit 24 of the ring connection control circuit 11B are received and the MAC of the ring connection control circuit 11A is received as in the normal state. The data is transferred to the processing unit 24.

Further, even when the PAUSE signal is output when the reception buffer has insufficient free space, the MAC processing unit 24 receives the frame from the switching unit 12 by the reception buffer by the frame reception operation.
Therefore, when the internal operation monitoring frame is transmitted from the MAC processing unit 24 of the ring connection control circuit 11B in the data frame transfer stop state, the MAC processing unit 24 of the ring connection control circuit 11A does not stop at the switching unit 12. Received.

[Effect of the first embodiment]
As described above, in this embodiment, the ring connection control circuit 11A connected in series to the sub-ring 51, the ring connection control circuit 11B connected in series to the sub-ring 52, and the ring connection control circuits 11A and 11B are connected. A data frame that is connected between the switching unit 12 that relays and forwards various frames to be exchanged and the first and second ring connection control circuits, and that instructs to stop the transfer of the data frame among the frames that are relayed and transferred by the switching unit 12 The ring connection control circuit 11A receives the frame when receiving the frame from the ring connection control circuit 11B via the switching unit 12 and the control signal line 14 for exchanging the transfer stop signal with each other. Data via the control signal line 14 according to the lack of free space in its own reception buffer Controlling the output of the frame transfer stop signal, the ring connection control circuit 11B, in response to detecting the presence or absence of a data frame transfer stop signal through a control signal line 14, controls the transfer of data frames to the switching unit 12.

As a result, the data frame transfer stop is not transmitted via the switching unit 12, but is directly transmitted from the ring connection control circuit 11A to the ring connection control circuit 11B via the control signal line 14. Stop can be avoided.
For this reason, even in a state where the free space of the reception buffer is insufficient, various frames transmitted from the MAC processing unit 24 of the ring connection control circuit 11B are transmitted via the switching unit 12 as in the normal state. The data is transferred to the MAC processing unit 24 of 11A.

Therefore, even when data frame transfer is stopped due to a lack of free space in the reception buffer, a monitoring frame such as an internal operation monitoring frame transmitted from the MAC processing unit 24 of the ring connection control circuit 11B is transmitted via the switching unit 12 to the ring. It reaches the MAC processing unit 24 of the connection control circuit 11A.
For this reason, even if data frame transfer is stopped due to a lack of free space in the reception buffer in the ring type switch, monitoring frames can be exchanged, and erroneous determination of failure occurring due to data frame transfer stop is suppressed. Is possible.

  In the present embodiment, in the frame reception operation of the MAC processing unit 24, when a monitoring frame such as an internal operation monitoring frame is received by the reception buffer via the switching unit 12, the frame is prioritized over other frames. You may make it perform the transfer process of the said monitoring frame. Thereby, the transfer delay of the monitoring frame in the MAC processing unit 24 can be shortened, and more accurate failure monitoring processing and further redundancy control processing can be realized.

[Second Embodiment]
Next, a ring type Ethernet system and a ring type switch according to the second embodiment of the present invention will be described with reference to FIG. FIG. 5 is a block diagram illustrating a configuration of a ring Ethernet system and a ring switch according to the second embodiment.
In the present embodiment, a case will be described in which the ring type switch 10 described in the first embodiment is used in parallel to duplicate the ring type switch that relay-connects the sub-rings 51 and 52.

The ring Ethernet system 2 is connected in series to the sub-ring 51, and is connected in series to the ring-type switch (first ring-type switch) 10X connected in series to the sub-ring, and to the sub-ring 51. A ring type switch (second ring type switch) 10Y connected in series to the ring is provided.
As a result, the ring type Ethernet system 2 has a configuration in which a ring type switch that relay-connects the two sub-rings 51 and 52 is duplicated by the two ring type switch 10X and the ring type switch 10Y.

  In the present embodiment, in these ring type switches 10X and 10Y, by performing duplexing control processing based on the operating state of the self and the other party exchanged with each other, one of them operates as the active system, and between the sub-rings 51 and 52 In addition to the relay connection, the other operates as a standby system and stops the relay connection between the sub-rings 51 and 52.

  Similar to the ring switch 10, these ring switches 10X and 10Y are provided with two ring connection control circuits 11A, a ring connection control circuit 11B, and a switching unit 12. The ring connection control circuits 11A and 11B are provided with two ports P1 and P2, respectively.

  The ring end point of the sub ring 51 is connected to the port P2 in the ring connection control circuit 11A of the ring type switch 10X and the port P2 in the ring connection control circuit 11A of the ring type switch 10Y. Similarly, the ring end point of the sub ring 52 is connected to the port P2 in the ring connection control circuit 11B of the ring type switch 10X and the port P2 in the ring connection control circuit 11B of the ring type switch 10Y.

  The port P1 in the ring connection control circuit 11A of the ring type switch 10X and the port P1 in the ring connection control circuit 11A of the ring type switch 10Y are connected by a relay path 53A, and one ring is connected via the sub ring 51. The frame that reaches the end point is relayed to the other end by the ring-type switches 10X and 10Y and the relay path 53A. Similarly, the port P1 in the ring connection control circuit 11B of the ring type switch 10X and the port P1 in the ring connection control circuit 11B of the ring type switch 10Y are connected by the relay path 53B, and one ring is connected via the sub ring 52. The frame that has reached the end point is relayed to the other end by the ring-type switches 10X and 10Y and the relay path 53B.

One of the ring-type switches 10X and 10Y operates in the active system and the other operates in the standby system based on the operation state of the self and the other party. When operating in the active system, communication between the sub-ring 51 and the sub-ring 52 becomes possible via the switching unit 12, and when operating in the standby system, the switching unit 12 allows the communication between the sub-ring 51 and the sub-ring 52. Communication is blocked.
In the present embodiment, an operation mode when operating in the active system is called an active mode, and an operation mode when operating as a standby system is called a backup mode. An operation mode during initialization processing executed immediately after power-on or immediately after failure recovery is called an initial (INITIAL) mode, and an operation mode when a failure occurs is called a failure (FAILURE) mode.

  The operation mode of the ring type switches 10X and 10Y immediately after power-on or immediately after failure recovery is automatically determined by the initialization process. As this operation mode determination method, for example, the other party's MAC address is acquired from the BPDU from the other party and compared with its own MAC address, the one with the smaller MAC address starts operation in the active mode, and the one with the larger MAC address There is a way to start operation in backup mode.

  In addition, after the initialization process, by executing the duplex control process on the ring type switches 10X and 10Y that are operating in the backup mode, if a failure occurs while operating in the active mode, the backup mode The other operating in the mode starts in the active mode. When the failure is recovered after switching the operation mode, the initialization process is executed in one of the ring type switches, and the operation is resumed in the backup mode.

FIG. 6 is a block diagram illustrating a configuration of a ring connection control circuit according to the second embodiment.
In the present embodiment, as shown in FIG. 6, the ring connection control circuits 11A and 11B of the ring type switches 10X and 10Y have the same function as that of the first embodiment, and the ring connection control circuit 11A. The MAC processing unit 24 and the MAC processing unit 24 of the ring connection control circuit 11B are connected by a control signal line 14 (14A, 14B). As a result, a PAUSE signal instructing to stop data frame transfer via the switching unit 12 is exchanged between the ring connection control circuits 11A and 11B.

The ring type switches 10X and 10Y according to the present embodiment have the following functions as functions for duplex control processing.
First, the RSTP processing unit 23 of the ring connection control circuit 11A (11B), in addition to the function of performing redundancy control processing for the sub-ring 51 (52) based on RSTP described in the first embodiment, It has a function to control switch duplication.

  FIG. 7 is a configuration example of the duplex control part of the ring type switch of the RSTP processing unit. The RSTP processing unit 23 includes, as main functions for duplex control processing, an internal operation monitoring function 31, a partner power supply confirmation function 32, a partner operation monitoring function 33, a MAC address comparison function 34, an initialization processing function 35, and a duplex function. A control processing function 36 is provided.

  The internal operation monitoring function 31 is a function for confirming the normality of each other by exchanging an internal operation monitoring frame (IHCF: Internal Health Check Frame) between the ring connection control circuits 11A and 11B via the switching unit 12. At this time, for the internal operation monitoring frame, for example, status information indicating the operation state of its own ring connection control circuit is added to a general MAC frame header including a destination MAC address, a transmission source MAC address, and a frame length. What is necessary is just composition.

The partner power check function 32 is a function for checking the power state of the partner ring switch based on a power status signal (POS: Power ON Status) from the partner ring switch.
The partner operation monitoring function 33 is a function for exchanging the operation states of each other by an extended BPDU frame (BPDU_e: Bridge Protocol Data Unit external) with the partner ring type switch via the relay paths 53A and 53B.

The MAC address comparison function 34 is a function that compares the partner MAC address acquired by the partner operation monitoring function 33 in the extended BPDU frame with its own MAC address.
The initialization processing function 35 is a function that executes initialization processing immediately after power-on or immediately after recovery from a failure, and determines its own operation mode at the start of operation based on the operation state of itself and the other party.
The duplexing control processing function 36 is a function that executes duplexing control processing after the initialization processing and switches its own operation mode based on the operating state of itself and the other party.

  Further, the transfer processing unit 25 transfers the MAC frame output from the MAC processing unit 21, 22, 24 to one of the MAC processing units 21, 22, 24 based on destination information included in the MAC frame. In addition to the function of controlling the restriction on the exchange of MAC frames with the MAC processing unit 24 based on its own operation mode set by the RSTP processing unit 23 and held in the storage unit (not shown); have.

  At this time, when the self is operating in the active mode, the transfer processing unit 25 cancels the restriction of the exchange of the MAC frame with the MAC processing unit 24, and the sub-ring 51 and the sub-ring 52 via the switching unit 12. When the transfer processing unit 25 is operating in the backup mode, the transfer processing unit 25 regulates the exchange of the MAC frame with the MAC processing unit 24 and the sub-ring 51 via the switching unit 12. And the communication between the sub ring 52 is cut off.

[Operation of Second Embodiment]
Next, operations of the ring type switch and the ring connection control circuit according to the present embodiment will be described with reference to FIGS. FIG. 8 is a transition diagram showing the operation mode of the ring type switch. FIG. 9 is a flowchart showing the initialization process of the ring connection control circuit. FIG. 10 is a flowchart showing the duplex control process of the ring connection control circuit.

  The ring-type switches 10X and 10Y transition between four operation modes according to the transition diagram of FIG. In the initial mode in which the ring type switches 10X and 10Y perform the initialization process immediately after the power is turned on or immediately after the failure recovery, when the internal operation monitoring function 31 detects an internal failure by itself, the ring type switches 10X and 10Y enter the failure mode. Further, when an internal failure is not detected and the MAC address of the other party is larger than that of the other party by the initial operation determination function, the mode transits to the active mode, and vice versa.

  On the other hand, when an internal failure is detected by the internal operation monitoring function 31 in the active mode and the backup mode, the mode is changed to the failure mode. Further, in the backup mode, when the duplex control processing function 36 detects a failure in the partner ring type switch, the mode is changed to the active mode.

[Initialization]
Next, the initialization process of the ring connection control circuit will be described in detail with reference to FIG. Here, the initialization process in the ring connection control circuit 11A of the ring type switch 10X will be described as an example.
The ring connection control circuit 11A of the ring type switch 10X executes the initialization process of FIG. 9 by the initialization process function 35 of the RSTP processing unit 23 immediately after power-on or immediately after recovery from a failure. At this time, also in the ring connection control circuit 11B of the ring type switch 10X, the initialization process of FIG. 9 is executed in parallel by the initialization process function 35 of the RSTP processing unit 23.

In the initialization process, the initialization processing function 35 of the RSTP processing unit 23 provided in the ring connection control circuit 11A first sets its own operation state held in the storage unit (not shown) to the initial mode. (Step 200).
Next, the initialization processing function 35 uses the internal operation monitoring function 31 to send an internal operation monitoring frame to the RSTP processing unit 23 of the counterpart ring connection control circuit 11B in the ring switch 10X via the switching unit 12. The normal operation of the partner ring connection control circuit 11B and the switching unit 12 is confirmed by exchanging the internal operation monitoring frame (step 201).

Here, when normal operation of the partner ring connection control circuit 11B and the switching unit 12 cannot be confirmed (step 201: NO), the initialization processing function 35 sets its operation state to the failure mode (step 210). Then, a series of initialization processing is completed.
On the other hand, when the normal operation of the counterpart ring connection control circuit 11B and the switching unit 12 can be confirmed (step 201: YES), the initialization processing function 35 uses the counterpart power supply confirmation function 32 to supply power from the counterpart ring type switch 10Y. Based on the signal, the power state of the other ring type switch 10Y is confirmed (step 202).

Here, when power-off is confirmed as the power state of the partner ring type switch 10Y (step 202: NO), the initialization processing function 35 sets its own operation state to the active mode (step 208), and a series of operations. End the initialization process.
On the other hand, when power-on can be confirmed as the power state of the partner ring type switch 10Y (step 202: YES), the initialization processing function 35 is transmitted by the partner operation monitoring function 33 via the MAC processing unit 22 and the relay path 53A. Then, the operating state of the counterpart ring type switch 10Y is confirmed by exchanging the extended BPDU frame with the RSTP processing unit 22 of the counterpart ring type switch 10Y (step 203).

Here, when the operation state of the partner ring type switch 10Y is the failure mode (step 203: YES), the initialization processing function 35 sets its own operation state to the active mode (step 208), and a series of initialization processes. Exit.
When the operation state of the partner ring type switch 10Y is not the failure mode (step 203: NO) and is in the active mode (step 204: YES), the initialization processing function 35 sets its own operation state to the backup mode. (Step 209), and a series of initialization processes are terminated.

On the other hand, when the operation state of the partner ring type switch 10Y is neither the failure mode nor the active mode (step 204: NO) and in the backup mode (step 205: YES), the initialization processing function 35 sets its own operation state to the active mode. (Step 208), and a series of initialization processing ends.
Further, when the operation state of the partner ring type switch 10Y is not the failure mode, the active mode, or the backup mode, that is, the partner ring type switch 10Y is also in the initialization process state (step 205: NO), the initialization process function 35 The MAC address comparison function 34 compares the partner MAC address acquired in the extended BPDU frame using the partner operation monitoring function 33 with its own MAC address (step 206).

  Here, when the own MAC address is smaller than the partner MAC address (step 207: YES), the initialization processing function 35 sets its own operation state to the active mode (step 208) and ends a series of initialization processing. . On the other hand, when the own MAC address is greater than or equal to the partner MAC address (step 207: NO), the initialization processing function 35 sets its own operation state to the backup mode (step 209), and a series of initialization processing Exit.

[Redundant control processing]
Next, the duplex control process of the ring connection control circuit will be described in detail with reference to FIG. Here, a duplex control process in the ring connection control circuit 11A of the ring type switch 10X will be described as an example.
When the ring connection control circuit 11A of the ring type switch 10X is operating in the backup mode after the initialization process, the duplex control process of FIG. 10 is executed by the duplex control process function 36 of the RSTP processing unit 23.

  The duplexing control processing function 36 of the RSTP processing unit 23 provided in the ring connection control circuit 11A is configured so that, in the duplexing control processing, first, the internal operation monitoring function 31 transmits the internal operation monitoring frame via the switching unit 12 to the ring type switch. The normal operation of the counterpart ring connection control circuit 11B and the switching unit 12 is confirmed by exchanging internal operation monitoring frames with the RSTP processing unit 23 of the counterpart ring connection control circuit 11B in 10X (step 220).

Here, when the normal operation of the counterpart ring connection control circuit 11B and the switching unit 12 cannot be confirmed (step 220: NO), the duplex control processing function 36 sets its own operation state to the failure mode (step 224). Then, a series of duplex control processing is terminated.
On the other hand, when the normal operation of the counterpart ring connection control circuit 11B and the switching unit 12 can be confirmed (step 220: YES), the duplex control processing function 36 uses the counterpart power supply confirmation function 32 to supply power from the counterpart ring type switch 10Y. Based on the signal, the power state of the counterpart ring type switch 10Y is confirmed (step 221).

Here, when power-off is confirmed as the power state of the partner ring type switch 10Y (step 221: NO), the duplex control processing function 36 sets its own operation state to the active mode (step 223), and a series of The duplex control process ends.
On the other hand, when the power-on state can be confirmed as the power state of the partner ring type switch 10Y (step 221: YES), the duplex control processing function 36 is transmitted by the partner operation monitoring function 33 via the MAC processing unit 22 and the relay path 53A. Then, the operating state of the counterpart ring type switch 10Y is confirmed by exchanging the extended BPDU frame with the RSTP processing unit 23 of the counterpart ring type switch 10Y (step 222).

Here, when the operation state of the counterpart ring type switch 10Y is not the failure mode (step 222: NO), the process returns to step 220 described above.
On the other hand, when the operation state of the partner ring type switch 10Y is the failure mode (step 222: YES), the duplex control processing function 36 sets its own operation state to the active mode (step 223) and performs a series of duplex control processing. finish.

[Effect of the second embodiment]
Thus, in this embodiment, in addition to the configuration of the first embodiment, the ring type switch connecting the two sub-rings is duplicated. In the first embodiment, even when data frame transfer is stopped due to a shortage, the monitoring frame can be exchanged, and it is possible to suppress erroneous determination of the occurrence of a failure caused by the stop of data frame transfer. In addition to this effect, even when a failure occurs in one ring type switch, Ethernet communication between sub-rings can be maintained with a normal ring type switch.

  Therefore, by providing a ring connection control circuit for each sub-ring and restricting transfer of the MAC frame including control information for redundancy control processing related to each sub-ring to the other sub-ring, Even in the case where the influence of the redundancy control processing in the network is suppressed, sufficient reliability can be obtained for the Ethernet communication between the sub-rings.

[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.

  1, 2 ... Ring type Ethernet system, 10 ... Ring type switch, 10X ... Ring type switch (first ring type switch), 10Y ... Ring type switch (second ring type switch), 11 ... Ring connection control circuit, 11A ... Ring connection control circuit (first ring connection control circuit), 11B ... Ring connection control circuit (second ring connection control circuit), 12 ... Switching unit, 13 ... Relay connection communication path, 14, 14A, 14B ... Control signal lines, 21, 22 ... MAC processing unit, 23 ... RSTP processing unit, 24 ... MAC processing unit, 25 ... transfer processing unit, 31 ... internal operation monitoring function, 32 ... counterpart power supply confirmation function, 33 ... counterpart operation monitoring function 34 ... MAC address comparison function, 35 ... initialization processing function, 36 ... duplex control processing function, 51 ... sub-ring (first sub-ring), 52 ... sub Ring (the second sub-ring), P1, P2 ... port (for ring connection) (for non-ring connection) P3 ... ports.

Claims (6)

A ring-type switch that is connected to a first sub-ring and a second sub-ring that connect a plurality of different nodes in a ring shape and relay-connects between the first and second sub-rings,
A first ring connection control circuit connected to the first sub-ring; a second ring connection control circuit connected to the second sub-ring; and between the first and second ring connection control circuits Data that is connected between the switching unit that relays and forwards various frames exchanged by the first and second ring connection control circuits, and that instructs to stop forwarding data frames among the frames that are relayed and forwarded by the switching unit A control signal line for exchanging frame transfer stop signals with each other,
When the first (second) ring connection control circuit is receiving a frame from the second (first) ring connection control circuit via the switching unit, the first (second) ring connection control circuit is configured to receive the frame. In response to a lack of free space in the reception buffer, the data frame transfer stop signal is output via the control signal line,
The second (first) ring connection control circuit stops transfer of a data frame to the switching unit in response to detection of the data frame transfer stop signal via the control signal line. Ring type switch. A first sub-ring connecting a plurality of nodes in a ring shape;
A second sub-ring for connecting a plurality of nodes different from the nodes of the first sub-ring in a ring shape;
The ring-type switch according to claim 1, wherein the switch is connected to the first sub-ring and connected to the second sub-ring, and the first sub-ring and the second sub-ring are connected to each other. A first ring-type switch that realizes Ethernet communication between a node connected to the first sub-ring and a node connected to the second sub-ring by relaying Ethernet communication between the first sub-ring and the second sub-ring A ring type Ethernet system characterized by comprising: The ring type Ethernet system according to claim 2,
The ring-type switch according to claim 1, wherein the switch is connected to the first sub-ring and connected to the second sub-ring, and the first sub-ring and the second sub-ring are connected to each other. A second ring-type switch that realizes Ethernet communication between the node connected to the first sub-ring and the node connected to the second sub-ring by relay-connecting the Ethernet communication therebetween In addition,
The first ring type switch and the second ring type switch perform duplex control processing based on the operating state of the self and the other party exchanged with each other, so that one of them operates as an active system and the first and second ring switches A ring-type Ethernet system, wherein the Ethernet communication between two sub-rings is relay-connected, and the other operates as a standby system to stop the relay connection between the first and second sub-rings. Ring-type switch control used in a ring-type switch that is connected to a first sub-ring and a second sub-ring that connect a plurality of different nodes in a ring shape and relay-connects between the first and second sub-rings A method,
The ring switch includes a first ring connection control circuit connected to the first sub-ring, a second ring connection control circuit connected to the second sub-ring, and the first and second A switching unit that relays and forwards various frames exchanged between the ring connection control circuits, and a data frame that is connected between the first and second ring connection control circuits and is relayed and forwarded by the switching unit. A control signal line for exchanging data frame transfer stop signals to instruct transfer stop,
When the first (second) ring connection control circuit is receiving a frame from the second (first) ring connection control circuit via the switching unit, the first (second) ring connection control circuit is configured to receive the frame. Outputting the data frame transfer stop signal via the control signal line in response to a lack of free space in the reception buffer;
The second (first) ring connection control circuit includes a step of stopping transfer of the data frame to the switching unit in response to detection of the data frame transfer stop signal via the control signal line. A ring type switch control method characterized by the above. A relay connection between a first sub-ring and a second sub-ring that connect a plurality of different nodes in a ring shape allows a node connected to the first sub-ring and the second sub-ring to be connected to each other. A ring type Ethernet system control method used in a ring type Ethernet system for realizing Ethernet communication with a connected node,
The ring-type Ethernet system includes the ring-type switch according to claim 1, and includes a first ring-type switch connected to the first sub-ring and connected to the second sub-ring.
The first ring-type switch relays Ethernet communication between the first sub-ring and the second sub-ring, so that the node connected to the first sub-ring and the second sub-ring A method for controlling a ring-type Ethernet system, comprising the step of realizing Ethernet communication with a node connected to the sub-ring. The ring type Ethernet system control method according to claim 5,
The ring-type switch according to claim 1, further comprising a second ring-type switch connected to the first sub-ring and connected to the second sub-ring,
The first ring type switch and the second ring type switch perform duplexing control processing based on the operating state of the self and the other party exchanged with each other, so that one of the first ring type switch and the second ring type switch operates as an active system and A ring-type Ethernet system comprising: a step of relay-connecting Ethernet communication between two sub-rings, and the other operating as a standby system to stop relay connection between the first and second sub-rings Control method.

Images