JP2007129606A - Transmission line system, frame transmitter therein, transmission line switching system and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase the processing speed for constructing and repairing the topology according to an original network protocol. <P>SOLUTION: Nodes (frame transmitters) 1-6 exchange a first control frame between adjacent nodes to watch transmission lines for failures. One node having detected a failure transmits a second control frame by multicast to inform other nodes that the one node transits to a master node, using a transmission line 10 around a B-system, thereby making the adjacent nodes transit to a terminal station node and the other nodes to an intermediate station node. The master node having detected the recovery from the failure multicast-transmits the second control frame using a transmission line 9 around an A-system, there is mediated between one or more master nodes having the second control frame to determine only one master node, and a network is re-constructed between the determined master node and those nodes transiting to the terminal station node as the mediation result. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a transmission line system in which a plurality of nodes having a plurality of ports transmit frames through a transmission line, a frame transmission apparatus in the system, a transmission line switching method, and a program.

As one form of the network, there is Ethernet (registered trademark) of layer 2 (layer 2 of the 7 layers of the OSI: Open Systems Interconnection reference model) having a ring configuration defined in IEEE 802.3. Further, STP (Spanning Tree Protocol) is known as a network configuration protocol (see, for example, Non-Patent Document 1).
STP is a protocol for logically forming a network into a tree structure so as not to create a loop configuration in a layer 2 network. This STP logically disconnects an unnecessary path (link) from a topology that physically includes a loop as an information transfer route, and constructs a logical tree structure without the loop. Further, when a physical or logical disconnection (disconnection) occurs between nodes constituting the tree structure, the tree structure once constructed can be reconstructed.

In order to construct the tree structure described above, one of the nodes is determined as a root, and the topology of the other nodes is exchanged between adjacent nodes, so that a node whose port connection destination is closer to the root is routed. The process of determining a node far from the port and route as the representative port is executed in all nodes. Then, the topology information of these hierarchical relationships is spread throughout the system to construct a tree structure.
On the other hand, in order to reconstruct the tree structure, the topology recovery message function is used. For example, this process is a function prepared to promptly notify the entire system when a disconnection occurs in the transmission path, prompt re-arbitration, and support a quick recovery from the disconnection state. Arbitration is performed between adjacent nodes in order to construct a logical topology, and a series of processes such as exchange of topology information, evaluation, and port state control are performed (see, for example, Patent Documents 1, 2, and 3).
ANSI: IEEE Std802.ID the spanning tree algorithm and protocol JP 2004-129100 A (paragraphs “0023” to “0027”, FIG. 1) JP 2004-282409 A (paragraphs “0056” to “0078”, FIG. 1) JP 2004-147172 A (paragraphs “0029” to “0035”, FIG. 1)

By the way, according to the above-described conventional port state control and topology repair method using STP, there are the following problems.
One is that it takes a long time on the order of several tens of seconds to construct a logical topology. Neighboring nodes exchange topology information with each other, compare their priorities, determine the hierarchical relationship between the nodes, and determine the logical role of the ports. In other words, if it is a root port, it can maintain a blocking state in which frame transfer is prohibited to each port, and if it is a representative port, it can transition to a forwarding state in which it is permitted. However, transition to the forwarding state is not possible immediately after selection as the root port or representative port, but as a frame transfer preparation state, a listening state that prevents temporary loop formation, and a frame transfer preparation state In the listening state, the learning state in which only frame reception is permitted is followed by the forwarding state described above, so that a considerable delay time occurs before the frame is actually transferred.

The other is that it takes more time to restore the logical topology when a failure occurs in the transmission path such as disconnection. When a disconnection occurs, a new logical topology that bypasses the cut point must be constructed. In order to quickly construct a logical topology, it is necessary to notify the entire network that a disconnection has occurred.
In STP, there is a Topology Change Notification (TCN) message as a means for notifying the occurrence of a failure to the entire network, but this is used only for clearing the node location storage cache, and its meaning as a trigger for exchanging topology information is do not have. Further, in the TCN message method, a TCN message is notified once to the root node, and then the root node notifies the entire network, and therefore it takes extra time in some cases.

  The present invention has been made on the basis of the above-described problems. A transmission path system, a frame transmission apparatus in the system, a transmission path switching method, and a program for speeding up processing for topology construction and topology repair are provided. The issue is to provide.

  In order to solve the above-described problem, a transmission line system according to the present invention is such that a plurality of nodes having a plurality of ports transmit frames through a transmission line, and are identified from among the plurality of ports. The transmission of the frame using any one of the above, and the transmission of the frame using one port different from the identified port, the termination state, using at least one port of the plurality of ports The node in any one of an intermediate station state that transmits a frame, a transmission path that terminates a transmission path, and the other terminal state that transmits the frame using a port connected to the intermediate station among the plurality of ports Means for establishing a network by setting the status of the network, means for monitoring a failure in the transmission path by exchanging a first control frame between adjacent nodes, and a result of the monitoring. By transmitting the second control frame using the transmission line, the other node is notified of the transition to one terminal state, the adjacent node is set to the other terminal state, and the other node is set to the intermediate station. And a means for transitioning to a state.

  According to the present invention, it is possible to provide a transmission line system, a frame transmission apparatus in the system, a transmission line switching method, and a program that speed up the processing for topology construction and topology repair.

FIG. 1 is a diagram showing a logical basic concept of a transmission line system according to an embodiment of the present invention, here, a bidirectional double ring type transmission line system.
In FIG. 1, reference numerals 1 to 6 are nodes as frame transmission apparatuses, and each is assigned a unique node number and a node state. These are assigned around the A system (clockwise), B A network is constructed by appropriately connecting through two transmission lines 9 and 10 around the system (counterclockwise).
In FIG. 1, reference numeral 1 denotes one terminal state (master node) (hereinafter referred to as A terminal station), which blocks transmission on the second port (port B) side (indicated by a thumbprint in the figure). It is a node. For this reason, in the A terminal station 1, the first port (port A) side is called the inside of the network, and the port B side is called the outside of the network. In the A terminal station 1, frame transmission is performed only on the port A side. Reference numeral 2 denotes the other terminal state (terminal station node) (hereinafter referred to as B terminal station), which is a node that terminates the transmission line 10 around the B system (counterclockwise). In the B terminal station 2, the port B side is called the inside of the network, and the port A side is called the outside of the network. In the B terminal station 2, the frame is transmitted only on the port B side.

Reference numerals 3 to 6 are intermediate stations, and frames can be transmitted to both the transmission path 9 around system A (clockwise) and the transmission path 10 around system B (counterclockwise). It is a node. The intermediate stations 3 to 6 are both connected to the network in the ports A and B, and frame transmission is performed bidirectionally on both the port A side and the port B side.
Reference numerals 7 and 8 are terminals (PC: Personal Computer) connected to the nodes assigned as the A terminal station 1, the B terminal station 2, and the intermediate stations 3 to 6, respectively. The terminals 7 and 8 generate user frames and exchange data using the transmission path 9 around the A system (clockwise) or the transmission path 10 around the B system (counterclockwise). Note that the thick arrows in FIG. 1 schematically show data exchange.

FIG. 2 is a diagram showing the types of frames transmitted and received in the transmission line system according to the present embodiment. In the figure, a broken line indicates a ring image of the ring type transmission line.
Here, in addition to the user frame c transmitted between the A terminal station and the B terminal station, the inter-adjacent frame a as a first control frame used between adjacent nodes, and the A terminal station are generated. A network control frame b is prepared as a second control frame for network control, which is multicast transmitted in the network and finally returned (received) to the A terminal station.

  Note that the user frame c includes a TCP (Transmission Control Protocol) and a UDP (User Datagram Protocol) frame transmitted and received by the own node as well as a frame flowing from a branch area LAN (Local Area Network) (not shown).

The inter-adjacent frame a is a frame for confirming the soundness (disconnection and connection) of the transmission path between adjacent nodes. Specifically, each of the nodes 1 to 6 in FIG. 1 communicates with each other by exchanging an inter-adjacent frame with each other's adjacent nodes to perform handshake. Here, the state in which the logical handshake with the adjacent node is completed is defined as link up. With this inter-adjacent frame, transmission path fault monitoring and transmission quality degradation are monitored.
The network control frame b includes a contention start trigger frame, a failure adjacent A declaration frame, a failure adjacent A transition frame, and a failure adjacent A transition response frame.

The contention start trigger frame is used to arbitrate one or more A terminal stations existing in the network to one node. Specifically, a plurality of A terminal stations compete with each other at the time of failure recovery, and have a priority. Based on the arbitration based on this, it becomes an opportunity to arbitrate one or more A terminal stations to one node.
The failure adjacent A declaration frame is used to declare that the own station is the failure adjacent A terminal station. Specifically, since the own station has the highest priority as the A terminal station, the contention start trigger The contention is canceled in response to the contention request by the frame, and the other node requests to transit to the intermediate station.
The failure adjacent A transition frame is used to declare that the own station has transitioned to the failure adjacent A terminal station. Specifically, since the own station has the highest priority as the A terminal station, the contention start trigger frame is used. The contention request is canceled and the other node requests to transit to the intermediate station.
The failure adjacent A transition response frame is used as a response frame for the node that has transmitted the failure adjacent A transition frame. Specifically, the failure adjacent A transition response frame is a failure adjacent A transition frame transmitted by the failure adjacent A terminal station. Is transmitted to the B terminal station, and thereby, a transmission path between the A terminal station and the B terminal station can be secured.

  FIG. 3 is a diagram showing a data format of a frame used in the transmission line system according to the present embodiment, and shows (a) an adjacent frame, (b) a network control frame, and (c) a user frame. ing.

As shown in FIG. 3A, the inter-adjacent frame includes fields of a destination address, a transmission source address, a tag, a frame length / type, a data area, and a CRC (Cyclic Redundancy Check). As shown in FIG. 3B, the network control frame is composed of fields of a destination address, a transmission source address, a tag, a frame length / type, a data area, and a CRC.
The frame identification number assigned to the data area is used to identify the contention start trigger frame, the failure adjacent A declaration frame, the failure adjacent A declaration frame, and the failure adjacent A transition response frame. This is information used to validate any one frame according to the priority assigned as control information when the frames compete. The tag is used for identification for assigning an arbitrary port to a plurality of VLANs (Virtual LANs). Further, the above-described inter-adjacent frame and network control frame are identified by a unique destination address value.

Also, as shown in FIG. 3C, the user frame is composed of fields of destination address, transmission source address, frame length / type, data area, and CRC.
Note that the inter-adjacent frame and the network control frame are transmitted using multicast. Therefore, each of the nodes 1 to 6 in FIG. 1 uses a node having a VLAN function that virtually divides a multicast domain into a plurality.

FIG. 4 is a block diagram showing the internal configuration of the data transmission apparatus according to this embodiment, and specifically shows the internal configuration of each of the nodes 1 to 6 shown in FIG.
The data transmission apparatus according to this embodiment includes a port A (11), a port B (12), a port state control unit 13, a reception buffer 14, a reception frame control unit 15, a transmission buffer 16, and a transmission frame. A control unit 17 and a network control unit 18 are included.

The port state control unit 13 exchanges adjacent frames between adjacent nodes 1 to 6 to perform a handshake periodically, and troubles the transmission paths 9 and 10 (FIG. 1) around the A system and the B system. Monitor.
The port state control unit 13 determines the destination address of the inter-adjacent frame or the network control frame received via the port A (11) and the port B (12), and determines the port B (12) and the port A. Whether to forward or block the transmission of the inter-adjacent frame or network control frame for (11) is determined and stored in the reception buffer 14 via the reception frame control unit 15.

  The network control unit 18 receives a network control frame transmitted by multicast using the transmission path 9 around the A system from the node that transitions to the faulty adjacent A terminal station when the failure of the transmission path 9 (10) is detected. A single A terminal station determined by arbitrating one or more A terminal stations that block transmission of user frames using the port B (12), and adjacent to the only A terminal station, A transmission line is reconstructed with a node that transitions to a faulty adjacent B terminal station that performs transmission through port B and terminates the transmission line 10 around the B system.

  Further, the network control unit 18 uses the frame identification number included in the network control frame stored in the reception buffer 14 so that the network control frame is transmitted around the transmission line 9 (10) around the A system or the B system where the failure has occurred. When recovery is detected, one of a conflict start trigger frame, a failure adjacent A declaration frame, a failure adjacent A transition frame, or a failure adjacent A transition response frame is determined, and the state transition of each node is controlled according to the determination result To do.

  Further, when transmitting the inter-adjacent frame and the network control frame based on the state of each node, the network control unit 18 reads the corresponding frame from the transmission buffer 16 via the transmission frame control unit 17 and transmits it to the port state control unit 13. At this time, the port state control unit 13 determines the tag included in the received corresponding frame, determines whether to transmit to the port A (11) or the port B (12), and transmits.

That is, the port state control unit 13 and the network control unit 18 described above function as means (1) to (4) listed below by cooperating with the port state control unit and the network control unit in other nodes. .
(1) Regarding the state of its own node, the transmission of the frame using the port B (12) is blocked, and the transmission of the A terminal station and the transmission path 10 around the B system using the port A (11) for the transmission of the frame is performed. Terminate and transmit the frame to the terminal station and transmission path that transmit the frame using port B (12), and transmit the frame bidirectionally using both port A (11) and port B (12) (2) A frame between adjacent nodes is exchanged with an adjacent node, a transmission path 9 around the A system, and a transmission path around the B system. (3) The node that has detected the failure as a result of monitoring transmits a network control frame by multicast using the transmission path 10 around the B system, and the node A The transition to the terminal As a result, means for transitioning the adjacent node around the B system to the terminal station and the other node to the intermediate station (4) As a result of monitoring, the A terminal station that has detected the recovery of the fault is the transmission line around the A system. 9 is used to transmit a network control frame by multicast, and arbitration is performed by one or more A terminal stations that have received this network control frame, and a transition is made to an intermediate station as a result of the arbitration. Means for Reconstructing Network with Node Transitioning to Terminal Station via Other Nodes Details of any of the above means will be described later.

6 to 13 are diagrams illustrating the operation of the transmission line system according to the present embodiment. Both are shown based on the physical configuration of the transmission line system of the present invention shown in FIG.
6 and 7 show network control procedures when a failure occurs, FIGS. 8 and 9 show network control procedures when a failure is recovered, and FIGS. 10 and 11 show network control procedures when a plurality of loops are integrated. FIG. 12 and FIG. 13 show the network control procedure when the power is turned on. 6 to 13, a circle indicates a port allocated as a relay port, a circle indicates a port allocated as a logical switching port, and ‖ indicates a blocking (logical disconnection) state. Also, in the figure, the numbers # 1 to # 6 assigned to the nodes correspond to the numbers 1 to 6 of the ports shown in FIG.

  The operation of the transmission line system according to the present embodiment will be described in detail below with reference to FIGS.

  First, network control when a failure occurs will be described with reference to FIGS. Here, node # 1 is assigned to the A terminal station, port B is blocked, node # 2 is assigned to the B terminal station, port A is blocked, and each of nodes # 3 to # 6 is networked as an intermediate station. Is described as being constructed.

Each node # 1 to # 6 confirms the soundness of the transmission line 9 (10) by periodically executing inter-adjacent frame communication (FIG. 6A). It is assumed that a failure has occurred due to the consecutive failure of the inter-adjacent frame n times. Here, it is assumed that a failure due to the disconnection has occurred between the nodes # 4 to # 5 by detecting that the frame has failed three times in succession. (FIG. 6B).
As a result, the node # 4 that detected the failure makes a transition to the failure adjacent A terminal station mode, and multicasts a frame (failure adjacent A transition frame) that declares that it has changed to the failure adjacent A terminal station around the B system. To do. In response, node # 5 transitions to the faulty adjacent B terminal mode (FIG. 6C).

On the other hand, the node # 1 receives the failed adjacent A transition frame, recognizes that there is another A terminal station, transitions to the intermediate station, and cancels blocking. Further, the node # 2 recognizes that the node # 1 is not the B terminal station when the node # 1 becomes the intermediate station, and transitions to the intermediate station to release the blocking (FIG. 7D).
Subsequently, since the node # 5 has transitioned to the failure adjacent B terminal mode, when receiving the failure adjacent A transition frame, the node # 5 multicasts a response frame (failure adjacent A transition response frame) around the A system (FIG. 7 (e)). ).
The node # 4 recognizes that there is a response from the terminal B by receiving the faulty adjacent A transition response frame, and stops transmitting the faulty adjacent A transition frame. Each of the nodes # 1 to # 6 continues to check the soundness of the transmission path by periodically communicating the adjacent frames (FIG. 7 (f)).

Next, network control at the time of failure recovery will be described with reference to FIGS. Here, a failure such as disconnection occurs between the nodes # 4 to # 5, the node # 4 becomes the faulty adjacent A terminal station, the port B is blocked, and the node # 5 becomes the faulty adjacent B terminal station. A is blocked, and the network is constructed with the nodes # 1 to # 3 and # 6 as intermediate stations.
Each node # 1 to # 6 confirms the soundness of the transmission line 9 (10) by periodically executing inter-adjacent frame communication (FIG. 8A).

Next, it is assumed that the failure has been recovered by connecting the disconnection that occurs between the nodes # 4 to # 5. Here, it is detected that the inter-adjacent frame communication has succeeded three times in succession, and the failure recovery between the nodes # 4 to # 5 is recognized (FIG. 8B).
When the port B is linked up, the node # 4 transitions from the faulty adjacent A terminal station mode to the logical disconnection A terminal station contention mode, and multicasts a contention start trigger frame around the A system. As a result, the node # 5 makes a transition from the failure adjacent B terminal station mode to the logically disconnected B terminal station mode when the port A is linked up (FIG. 8C).

The intermediate station and the B terminal station ignore the contention start trigger frame transmitted from the node # 4. For this reason, the node # 4 recognizes that only the node A exists in the network by receiving the contention start trigger frame transmitted by the node # 4. As a result, the node # 4 transitions from the logical disconnection A terminal station contention mode to the logical disconnection A terminal station mode (FIG. 9D).
The nodes # 1 to # 6 continue to check the soundness of the transmission line 9 (10) by periodically exchanging frames between adjacent nodes thereafter (FIG. 9 (e)).

  Next, network control at the time of integrating a plurality of loops will be described with reference to FIGS. Here, it is assumed that a failure has occurred between the nodes # 1 and # 2, and between the nodes # 4 and # 5, and the node # 1 and the node # 4 are the failure adjacent A terminal stations, blocking the port B, and the node # 2 and node # 5 become the faulty adjacent B terminal station ports, blocking port A, and the network is constructed with node # 3 and node # 6 as intermediate stations.

Each node # 1 to # 6 confirms the soundness of the transmission line 9 (10) by periodically performing inter-adjacent frame communication (FIG. 10A).
Here, it is assumed that the failure between the nodes # 1 and # 2 has been recovered. That is, when the inter-adjacent frame is succeeded three times in succession, the node # 1 serving as the faulty adjacent A terminal station detects the fault recovery between the nodes # 1 and # 2 (FIG. 10B).
Subsequently, the node # 1 transitions from the failure adjacent A terminal mode to the logical disconnection A terminal contention mode when the port B is linked up, and multicast-transmits the contention start trigger frame around the A system. Further, the node # 2 transitions from the failure adjacent B terminal station mode to the logically disconnected B terminal station mode when the port A is linked up (FIG. 10 (c)).

Nodes # 3 and # 6 as intermediate stations and nodes # 2 and # 5 as B terminal stations ignore the contention start trigger frame transmitted from node # 1. The node # 4 receives the contention start trigger frame. At this time, the node # 4 is in the faulty adjacent A terminal mode and has the highest priority. Therefore, the failure adjacent A declaration frame is transmitted to the node # 1, which is the transmission source of the contention start trigger frame, to notify that the own node has high priority (FIG. 11 (d)).
Node # 1 receives the faulty adjacent A declaration frame and recognizes that there is an A terminal with high priority in the network. For this reason, a transition is made from the logical disconnection A terminal station contention mode to the intermediate station to release the blocking. Also, node # 2 recognizes that its own node is not a B terminal because node # 1 becomes an intermediate station, and transitions to the intermediate station to release blocking. Each node continues to check the soundness of the transmission path by periodically exchanging frames between adjacent nodes (FIG. 11 (e)).

Finally, a network control procedure at power-on will be described with reference to FIGS. Here, it is assumed that the node # 1 and the node # 2 are started up among the three nodes, and the node # 3 is still powered off (FIG. 12A).
First, the nodes # 1 and # 2 that are powered on transition from the power-off state to the isolated mode. Subsequently, when the inter-adjacent frame succeeds three times in succession and the nodes # 1 and # 2 link up, the node # 1 changes from the isolated mode to the faulty adjacent B terminal, and the node # 2 A transition is made to the faulty adjacent A terminal mode (FIG. 12B).

Next, assume that node # 3 is started up. As a result, the node # 3 transitions from the power-off state to the isolated mode (FIG. 12C).
Subsequently, the node # 3 transitions from the isolated mode to the faulty adjacent B terminal mode when the inter-adjacent frames succeed three times in succession. Also, node # 1 transitions from the failure adjacent B terminal station mode to the intermediate station when port A is linked up, and releases blocking (FIG. 13 (d)).

Subsequently, when the inter-adjacent frame between the node # 2 and the node # 3 succeeds three times in succession, the node # 3 transitions from the faulty adjacent B terminal mode to the logically disconnected B terminal mode. Further, the node # 2 transitions from the failure adjacent A terminal mode to the logical disconnection A terminal contention mode when the port B is linked up, and multicasts a contention start trigger frame around the A system (FIG. 13). (E)).
At this time, the node # 1 that is the intermediate station and the node # 3 that is the B terminal station ignore the contention start trigger frame transmitted from the node # 2. Also, since the contention start trigger frame transmitted by the node # 2 is returned, the node # 2 recognizes that the A terminal station exists only in the network. Node # 2 then transitions from the logical disconnection A terminal station competition mode to the logical disconnection A terminal station mode.
The nodes # 1 and # 3 continue to check the soundness of the transmission path by periodically exchanging frames between adjacent nodes thereafter (FIG. 13 (f)).

  FIG. 14 is a diagram illustrating state transition between modes of the transmission line system according to the present embodiment. The operation | movement demonstrated using FIGS. 6-13 is typically shown. In the figure, “up” indicates a state in which the adjacent station is logically connected, and “down” indicates a state in which it is logically disconnected.

As described above, according to the present invention, a plurality of nodes # 1 to # 6 perform frame transmission using the transmission path 9 around the A system and the transmission path 10 around the B system. A terminal station that blocks transmission of a control frame using the port B, terminates a transmission path around the B system using the port A with respect to the transmission of the frame, and transmits a frame using the port B (3) A transmission path system is constructed by transmitting / receiving frames to / from both transmission paths and allocating them to any one of intermediate nodes that perform bidirectional transmission of frames using both port A and port B. is there.
At this time, each of the nodes # 1 to # 6 (frame transmission apparatus) exchanges a first control frame with an adjacent node to monitor a transmission path failure. Then, the node that has detected the failure transmits the second control frame by multicast using the transmission path 10 around the B system, notifies other nodes that it has transitioned to the A terminal station, The node to be transferred is changed to a terminal station node, and the other nodes are changed to intermediate station nodes. On the other hand, the A terminal station that has detected the recovery of the failure multicasts the second control frame using the transmission path 9 around the A system, and arbitrates by one or more A terminal stations that have received the second control frame. The network between the only A terminal station that is determined and determined and the node that transitions to the terminal station node via the other node that transitions to the intermediate station node as a result of arbitration is reconstructed.

As a result, in the bi-directional double ring transmission line system, detection of occurrence and recovery of a transmission line failure can be realized by a handshake in which the first control frame is exchanged between adjacent nodes. A node that detects the occurrence of a failure makes a transition to the A terminal, performs arbitration by multicasting the second control frame, and reconstructs the network, thereby shortening the time required for constructing the logical topology.
The second control frame also has a meaning as a trigger for exchanging topology information. Since the second control frame is simultaneously notified to each node by multicast, the processing for topology construction and topology restoration is accelerated. can do.

In addition, according to the above-described embodiment of the present invention, only the disconnection of the transmission line is illustrated as the failure. However, for the node failure and the like, the adjacent failure detection node operates as the A terminal station. The same effect can be obtained.
Further, the functions of the port state control unit 13, the reception frame control unit 15, the transmission frame control unit 17, and the network control unit 18 shown in FIG. 5 are realized by a program, and this program is stored in a computer-readable recording medium. However, the bidirectional double ring transmission line system and the frame transmission apparatus of the present invention described above can also be constructed by the CPU serving as the control center of each node reading and executing the program sequentially.

It is a figure which shows the logical basic concept of the transmission-line system concerning embodiment of this invention. It is a figure which shows the kind of flame | frame transmitted / received in the transmission line system concerning this embodiment. It is a figure which shows the data format of the frame used with the transmission line system concerning this embodiment, (a) Inter-adjacent frame, (b) Network control frame, (c) User frame, each data format is shown. It is a block diagram which shows the internal structure of the data transmission apparatus concerning this embodiment. It is a figure which shows the physical fundamental structure of the transmission line system concerning this embodiment. It is a figure which shows the procedure of the network control at the time of the failure generation of the transmission line system concerning this embodiment. It is a figure which shows the procedure of the network control at the time of the failure generation of the transmission line system concerning this embodiment. It is a figure which shows the procedure of the network control at the time of the failure recovery of the transmission line system concerning this embodiment. It is a figure which shows the procedure of the network control at the time of the failure recovery of the transmission line system concerning this embodiment. It is a figure which shows the procedure of the network control at the time of multiple loop integration of the transmission line system concerning this embodiment. It is a figure which shows the procedure of the network control at the time of multiple loop integration of the transmission line system concerning this embodiment. It is a figure which shows the procedure of the network control at the time of power activation of the transmission line system concerning this embodiment. It is a figure which shows the procedure of the network control at the time of power activation of the transmission line system concerning this embodiment. It is a figure which shows the state transition between the modes of the transmission line system concerning this embodiment.

Explanation of symbols

1-6 nodes (frame transmission equipment)
7, 8 Terminal 9, 10 Transmission path (A system, B system)
11 Port A (first port)
12 Port B (second port)
13 Port State Control Unit 14 Reception Buffer 15 Reception Frame Control Unit 16 Transmission Buffer 17 Transmission Frame Control Unit 18 Network Control Unit

Claims (13)

A transmission line system in which a plurality of nodes having a plurality of ports transmit frames through a transmission line,
Blocking transmission of a frame using any one of the plurality of ports specified, and one terminal state using a port different from the specified port for transmission of the frame, of the plurality of ports Intermediate station state for transmitting the frame using at least one port, termination of the transmission path, and the other terminal state for transmitting the frame using a port connected to the intermediate station among the plurality of ports A means for setting a state of the node to any one of the above and constructing a network;
Means for exchanging a first control frame between adjacent nodes to monitor a failure in the transmission path;
As a result of the monitoring, by transmitting the second control frame using the transmission line, the other node is notified of the transition to one terminal state, the adjacent node is changed to the other terminal state, Means for transitioning the node to the intermediate station state;
A transmission line system comprising: A transmission line system in which a plurality of nodes having a first port and a second port transmit frames using transmission lines around the A system and the B system,
Frame transmission using the second port is blocked, and transmission of the frame is terminated by a master node that uses the first port and a transmission path around the B system, and the frame is transmitted using the second port. The intermediate station node that transmits the frame to the transmission path and performs the bidirectional transmission of the frame using both the first port and the second port. A means for setting the node state and building the network;
Means for exchanging a first control frame between adjacent nodes to monitor a failure in the transmission path;
As a result of the monitoring, by multicast transmission of the second control frame using the transmission path around the B system, the transition to the master node is notified to the other nodes, the adjacent node to the terminal station node, Means for transitioning another node to an intermediate station node;
As a result of the monitoring, the master node that has detected the recovery of the failure multicasts the second control frame using the transmission path around the system A, and receives the second control frame. Means for re-establishing a network between the only master node that is determined by arbitration according to, and the node that transitions to the terminal station node via the other node that transitions to the intermediate station node as a result of the arbitration; ,
A transmission line system comprising: The plurality of nodes are:
The first control frame periodically performs handshake with the adjacent node to notify the status of the own node and monitor the failure of the transmission path, and the logical handshake with the adjacent node is completed. 3. The transmission line system according to claim 1, wherein execution of the state transition of the node is permitted when triggered by this. The plurality of nodes are:
(1) A contention start trigger frame that triggers mediation and arbitration for one or more master nodes when detecting failure recovery of a transmission path in which a failure has occurred;
(2) Since the own node is the master node having the highest priority, the failure adjacent A declaration is declared by requesting and declaring the contention by the contention start trigger frame to the other node to transit to the intermediate station node. Frame,
(3) Since the own node has the highest priority as a master node, it cancels the contention by the contention start trigger frame, requests other nodes to transition to the intermediate station node, detects the failure A failure adjacent A transition frame declaring that a transition has been made to the failure adjacent A terminal,
(4) Notifying that the failure adjacent A transition frame transmitted by the own node has reached the terminal station node, indicating that a transmission path between the failure adjacent A terminal station and the terminal station node has been secured. The second control frame comprising a fault adjacent A transition response frame,
The transmission path system according to any one of claims 1 to 3, wherein each of the nodes is recognized and state transition of each node is controlled based on the recognition result. A frame transmission apparatus in a transmission path system in which a plurality of nodes having a first port and a second port transmit a frame using transmission paths around the A system and the B system,
A port state control unit for exchanging a first control frame between adjacent nodes and periodically performing handshake to monitor a failure in the transmission path;
By detecting a failure in the transmission path, a node that transitions to the master node receives a second control frame that is multicast-transmitted using a transmission path around the system A, and transmits a user frame that uses the second port. A single master node determined by arbitrating one or more master nodes that block transmission, and adjacent to the single master node, the frame is transmitted by the second port, and a transmission path around the B system is established. A network control unit for reconstructing a transmission path with a terminating station node to be terminated;
A frame transmission apparatus comprising: The port state control unit
Control of the second port and the first port by determining destination addresses of the first control frame and the second control frame received via the first port and the second port 6. The frame transmission apparatus according to claim 5, wherein the frame transmission apparatus determines whether to forward or block the transmission of the frame, and stores the control frame received via the reception frame control unit in a reception buffer. The network control unit
Due to the frame identification number included in the second control frame, the second control frame (1) competes with one or more master nodes when it detects failure recovery of the transmission path where the failure has occurred. Or a conflict start trigger frame that triggers arbitration, or (2) because the own node is the master node having the highest priority that has detected that a failure has occurred in the transmission path, Either a failure adjacent A declaration frame that is requested to declare to other nodes to transit to the intermediate station node, or (3) because the own node has the highest priority as a master node, A failure adjacent A transition frame that cancels contention, requests other nodes to transition to an intermediate station node, and declares transition to a failure adjacent A terminal station, 4) A failure adjacent A transition frame notifying that the failure adjacent A transition frame transmitted by the own node has reached the terminal station node and indicating that a transmission path is secured between the master node and the terminal node. Determine whether
7. The frame transmission device according to claim 5, wherein state transition of the node is controlled according to the determination result. The network control unit
When transmitting the first and second control frames based on the node state, the port state control unit reads the control frame from the transmission buffer via the transmission frame control unit, and transmits the control frame to the port state control unit. The method of determining a tag included in the received corresponding control frame, determining whether to transmit to the first port or to transmit to the second port, and transmitting the tag. 8. The frame transmission apparatus according to any one of 7 above. A transmission path switching method in a transmission path system in which a plurality of nodes having a first port and a second port perform transmission / reception of frames using transmission paths around A system and B system,
A first step in which each node performs a handshake by exchanging a first control frame between adjacent nodes, and monitors a failure occurring in the transmission path;
As a result of the monitoring, (1) the node detecting the failure blocks the transmission of the frame using the second port, and multicasts the second control frame from the first port using the transmission path around the B system. (2) A node adjacent to the transitioned master node terminates the transmission path around the B system, and notifies the other node of the transition to the master node. (3) The other node transmits the second control frame to the transmission path, and transmits both the first port and the second port. A second step of transitioning to an intermediate station node that transmits frames using
The master node that has detected the recovery of the failure multicasts a second control frame using a transmission path around the system A, and prompts arbitration by one or more master nodes that have received the second control frame; The only master node determined as a result of the arbitration reconstructs the network between itself and the node that transitions to the terminal station node via other nodes that transition to the intermediate station node as a result of the arbitration A third step;
A transmission line switching method in a transmission line system. The second step includes
A master node that detects a fault on the transmission path due to the failure of the handshake and makes a transition to the faulty adjacent A terminal mode declares that the master node that has transitioned to the faulty adjacent A terminal mode is a faulty neighboring A A sub-step for multicast transmission of the transition frame to other nodes using a transmission path around system B;
A sub-step in which a node adjacent to the master node that has received the failed adjacent A transition frame transitions to a failed adjacent B terminal mode;
The node that was operating as the master node before the occurrence of the failure receives the failed adjacent A transition frame, knows that there is another master node, and releases the blocking of the second port in order to transition to the intermediate station node Substeps to
The node that was operating as the terminal station node before the occurrence of the failure in the transmission path transitions to the intermediate station node in response to the transition of the node that was operating as the master node to the intermediate station node. A substep to unblock the port;
The new terminal station node that has transitioned to the faulty adjacent B terminal mode receives the faulty adjacent A transition frame, and uses the faulty adjacent A transition response frame as a second control frame using a transmission path around the A system. A substep for multicast transmission to other nodes;
The master node that has transitioned to the faulty adjacent A terminal mode receives the faulty adjacent A transition response frame, recognizes that there is a response from the terminal station node, and stops multicast transmission of the faulty adjacent A transition frame Substeps to
The transmission path switching method in the transmission path system according to claim 9, comprising: The third step includes
The master node that has detected the recovery from the failure recognizes that the second port has succeeded in handshaking, and changes from the failed adjacent A terminal mode to the logically disconnected A terminal contention mode that arbitrates one or more master nodes. A sub-step of making a multicast transmission of a contention start trigger frame as a second control frame that triggers contention start to the other nodes using a transmission path around the A system;
A sub-step in which the terminal station node adjacent to the master node recognizes that the first port has succeeded in handshaking and transitions from the failed adjacent B terminal mode to the logically disconnected B terminal mode;
The master node recognizes that only the master node exists in the network by receiving the contention start trigger frame transmitted by itself, and transitions from the logical disconnection A terminal station conflict mode to the logical disconnection A terminal mode. Substeps to
The transmission path switching method in the transmission path system according to claim 9 or 10, characterized by comprising: The third step includes
Logical disconnection A terminal station contention in which the first master node that detected the recovery of the failure recognizes that the second port has succeeded in handshaking and arbitrates one or more master nodes from the failure adjacent A terminal mode. A sub-step of transitioning to a mode and multicasting a contention start trigger frame as a second control frame that triggers contention start to another node using a transmission path around the A system;
The first terminal station node adjacent to the first master node recognizes that the first port has succeeded in handshaking, and transitions from the failed adjacent B terminal mode to the logically disconnected B terminal mode. Substeps,
The second master node that has received the contention start trigger frame is in the faulty adjacent A terminal mode and has the highest priority, so that the first master that is the transmission source of the contention start trigger frame A substep of sending a faulty neighbor A declaration frame as a second control frame to the node;
The first master node that has received the faulty adjacent A declaration frame recognizes that there is a second master node having a high priority in the network, and transitions from the logical disconnection A terminal station mode to the intermediate station mode; A sub-step for unblocking the second port;
The first terminal station node recognizes that it is not a terminal station node after the first master node transitions to the intermediate station mode, transitions to the intermediate station mode, and A substep to unblock,
The transmission path switching method in the transmission path system according to claim 9 or 10, characterized by comprising: A program used in a frame transmission apparatus in a transmission line system in which a plurality of nodes having a first port and a second port transmit frames using transmission lines around the A system and the B system,
A process of exchanging a first control frame between the adjacent nodes and periodically performing a handshake to monitor a failure of the transmission path;
A process of receiving a second control frame multicast-transmitted using a transmission path around the A system by a node that transitions to the master node by detecting a failure of the transmission path by the handshake;
A single master node determined by arbitrating one or more master nodes that block user frame transmission using the second port, and transmission of the frame by the second port, transmission around the B system A process of reconstructing a transmission path with a terminal station node that terminates the path;
A program that causes a computer to execute.

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