WO2010116406A1 - Multi-ring network system, ring node device, and load distribution method - Google Patents

Abstract

A multi-ring network system relays data as relay data between different ring networks through a relay link connecting between pair nodes and comprises a plurality of relay links. In the system, an RPR ring node device (1-5) at a frame transmission source selects on a per data flow basis a relay link to be used for a relay, holds a correspondence between the data flow and the selected relay link, determines, based on the correspondence, a relay link corresponding to data flow identification information included in a frame to be transmitted, and transmits the frame by setting, as a terminal node, pair nodes to be connected to the determined relay link within an intra-ring network. The pair nodes, when the terminal node of the received frame is a self-node, transfer the received frame to the relay link and, when receiving relay data from the relay link to which the pair nodes are connected, transmit the relay data to the intra-ring network.

Description

Multi-ring network system, ring node device, and load balancing method

The present invention relates to a multi-ring network system and a ring node device that connect ring networks by a plurality of relay links.

In a ring network, a function for bypassing a failure in the event of a ring failure is specified. For example, a bidirectional double ring is configured, and each ring node that configures the ring network advertises its physical address on the ring, and each ring node collects the advertisement information and arranges the order of the nodes (topology When a packet is transmitted on the ring, a ring of a system close to the physical address of the destination is selected with reference to the topology map and transmitted. Each node has a function of quickly detecting a failure location on the ring and switching a route by constantly monitoring the failure information that each node periodically transmits (failure bypass function at the time of ring failure). , Protection function).

As a ring network having such a function, for example, there is RPR defined in Non-Patent Document 1 below. In addition to the features described above, RPR defines a fairness function for maintaining bandwidth fairness among ring nodes when a large number of users freely consume ring bandwidth at best effort. The RPR protection function detects the location of the failure based on the failure information. However, the RPR has a rule that the failure bypass time is a maximum of 50 milliseconds, and the operation from the failure occurrence to the switching of the transmission direction of the RPR data frame is performed. Implement at high speed.

RPR defines the specifications of the media access sublayer of the data link layer. For example, Ethernet (registered trademark) for packet communication, SDH (Synchronous Digital Hierarchy) for synchronous communication, etc. It can be applied to the physical layer, and has a feature that does not limit the physical layer.

On the other hand, there is a multi-ring network system in which a plurality of ring networks are connected in a multi-ring manner as a method for dealing with a large-scale network using a ring network. In multi-ring connection, ring networks are connected by relay links. Generally, a redundant node configuration is used to improve reliability, and a plurality of relay links exist.

IEEE, “IEEE 802.17 Resilient Packet Ring (RPR, IEEE Std 802.17)”, 2004

However, although the conventional multi-ring network system includes a plurality of relay links for redundancy, any one of the relay links is used as a path for actual communication in order to avoid a loop. Therefore, there is a problem that the load is concentrated on one relay link, and there are unused relay links, and the bandwidth cannot be used effectively.

The present invention has been made in view of the above, and in a multi-ring network system, when a plurality of relay links are provided, the multi-ring network system, the ring node device, and the load distribution method capable of improving the bandwidth utilization efficiency The purpose is to obtain.

In order to solve the above-described problems and achieve the object, the present invention includes a plurality of ring networks, and at least one of the ring node devices constituting the ring network is a pair node. A multi-ring network system for relaying data transmitted / received via a relay link, which is a link connecting a pair of pair nodes, as relay data, comprising a plurality of the relay links, and a ring that is a frame transmission source For each data flow, the node device selects a relay link to be used for relaying the data flow and holds the correspondence between the data flow and the selected relay link. On the other hand, the node device uses the data flow identification information included in the frame to be transmitted. The corresponding relay link is determined based on the correspondence and the ring to which it belongs A pair node connected to the determined relay link in the own ring network which is a network is set as a terminal node of the frame, and the frame is transmitted to the own ring network. The pair node transmits the frame received from the own ring network. When the terminal node is its own node, the received frame is transferred as relay data to the relay link to which the terminal node is connected, and when relay data is received from the relay link to which the terminal node is connected, It is characterized by sending itself to the ring network as a transmission source.

The multi-ring network system, the ring node device, and the load distribution method according to the present invention select a relay link to be used for relaying a frame of the flow by the ring node device on the frame transmission side for each data flow, and for each flow. The pair node connected to the relay link is set as the termination node and the frame is transmitted to the ring network. The pair node forwards the frame set as the termination node to the relay link to which the pair node is connected. As a result, the band utilization efficiency can be improved.

FIG. 1 is a diagram illustrating a functional configuration example of the RPR ring node device according to the first embodiment. FIG. 2 is a diagram illustrating a configuration example of the multi-ring network system according to the first embodiment. FIG. 3 is a configuration diagram of a multi-ring network system for explaining an operation example in a normal state. FIG. 4 is a diagram for explaining an operation when a failure occurs according to the first embodiment. FIG. 5 is a diagram illustrating a functional configuration example of the RPR ring node device according to the second embodiment. FIG. 6 is a multi-ring network system configuration diagram illustrating an example of normal operation of the second embodiment. FIG. 7 is a diagram for explaining an operation when a failure occurs according to the second embodiment.

1, 1-1 to 1-8, 1a, 1a-1 to 1a-8 RPR ring node device 2, 2a, 3, 3a Network 4 West relay link 5 East relay link 6 Inner ring 7 Outer ring 8-1, 8 -2 Terminal 11 Concentration SW unit 12 RPR interface transmission unit 13, 13a RPR interface reception unit 14 Protection unit 15 Topology management unit 16 Outer ring reception unit 17 Outer ring drop determination unit 18 Outer ring transmission unit 19 Inner ring transmission unit 20 Inner ring Drop determination unit 21 Inner ring reception unit 22 Relay link port 23 Other port 24 Reception flow filtering unit 30, 32 Non-forwarding frame 31, 33 Failure

Hereinafter, embodiments of a multi-ring network system, a ring node device, and a load distribution method according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram illustrating a functional configuration example of a first embodiment of an RPR ring node device according to the present invention. As shown in FIG. 1, an RPR ring node device 1 according to the present embodiment is a device that functions as an RPR ring node, and includes a line switch (SW) unit 11, an RPR interface transmission unit 12, an RPR interface reception unit 13, protection. A unit 14, a topology manager 15, an outer ring receiver 16, an outer ring drop determiner 17, an outer ring transmitter 18, an inner ring transmitter 19, an inner ring drop determiner 20, and an inner ring receiver 21. The RPR ring node device 1 includes a relay link port 22 and a port other than the relay link port 22, and includes another port 23 for connecting to, for example, a terminal.

FIG. 2 is a diagram illustrating a configuration example of the multi-ring network system according to the present embodiment. As shown in FIG. 2, the multi-ring network system according to the present embodiment includes RPR ring node devices 1-1 to 1-8, and the RPR ring node devices 1-1 to 1-4 are ring node networks. 2 and RPR ring node devices 1-5 to 1-8 constitute a network 3 which is a ring node network. The RPR ring node devices 1-1 to 1-8 each have the same configuration as the RPR ring node device 1 shown in FIG. Further, the RPR ring node device 1-2 and the RPR ring node device 1-6 are set as a West pair node, and the RPR ring node device 1-3 and the RPR ring node device 1-7 are set as an East pair node. The two networks 2 and 3 are connected by two links, a West relay link 4 that connects the West pair nodes and an East relay link 5 that connects the East pair nodes. In addition, the network 2 and the network 3 have two-way rings, an inner ring 6 and an outer ring 7.

Returning to FIG. 1, the function of the RPR ring node 1 will be described. The relay link port 22 is an input / output port for a frame from a relay link that connects between ring node networks, such as the West relay link 4 and the East relay link 5 in FIG. The line collection switch unit 11 receives a MAC frame of a MAC (Media Access Control) frame input from the relay link port 22 or the other port 23, transmits a frame output to the relay link port 22 or the other port 23, Switching.

The RPR interface transmitting unit 12 generates an RPR data frame or an RPR control frame by adding an RPR header to the MAC frame received via the line concentrating switch unit 11, and the topology acquired from the topology management unit 15 in the received MAC frame. Generating an RPR control frame to which the information and the protection information acquired from the protection unit 14 are added, and selecting whether to add to one or both of the inner ring 6 and the outer ring 7 based on the topology information and the protection information, Based on the selection result, the generated frame is output to one or both of the outer ring transmitter 18 and the inner ring transmitter 19.

Further, the RPR interface transmission unit 12 determines usable relay links based on multi-ring information that is information relating to relay link failures and pair node failures, and based on a predetermined relay link selection rule from among usable relay links. For each data flow, the relay link used for relaying the frame of the data flow is selected, and the end node of the frame is set for each data flow based on the selected relay link, network configuration, and the like. In addition, there is no restriction | limiting in particular about the acquisition method of multiring information, For example, it acquires based on the data and relay link which are transmitted / received within a ring network.

The RPR interface receiving unit 13 identifies whether the frame is an RPR data frame or an RPR control frame based on the RPR frame received from the inner ring 6 or the outer ring 7. Further, the RPR interface receiving unit 13 extracts predetermined information necessary for the processing of the protection unit 14 and the topology management unit 15 from the received RPR frame, and the extracted information is respectively protected by the protection unit 14 and the topology management unit 15. Notify Further, the RPR interface reception unit 13 extracts a MAC frame from the received RPR data frame, and delivers the extracted MAC frame to the line concentration switch unit 11.

The protection unit 14 grasps the failure status on the ring in the same manner as a general ring network protection function described later, and notifies the topology management unit 15 of the failure information as protection information.

The topology management unit 15 stores the number of HOPs to each destination RPR ring node device on its own ring network as a table and manages it as topology information. The outer ring receiving unit 16 checks whether there is an error in the frame received from the outer ring 7, and outputs the received frame after the check to the outer ring drop determination unit 17. The inner ring reception unit 21 checks whether there is an error in the frame received from the inner ring 6 and outputs the received frame after the check to the inner ring drop determination unit 20.

The outer ring drop determination unit 17 determines whether the received frame received via the outer ring receiving unit 16 is to be relayed or dropped (destroyed), and when relaying, forwards the received frame to the relay link. The RPR interface receiving unit 13 outputs the received frame to the outer ring transmitting unit 18 when not relaying and dropping. The inner ring drop determination unit 20 determines whether the received frame received via the inner ring reception unit 21 is relayed or dropped, and when relaying, the RPR interface is used to transfer the received frame to the relay link. When the data is output to the reception unit 13 and is not relayed and dropped, the reception frame is output to the inner ring transmission unit 19. Further, the outer ring drop determination unit 17 and the inner ring drop determination unit 20 determine whether or not the frame ends based on the TTL (Time To Live) of the received frame, and do not transfer to the relay link if it is not the end. Furthermore, when the outer ring drop determination unit 17 and the inner ring drop determination unit 20 receive a frame whose source is another pair node, the frame is not transferred to the relay link.

The outer ring transmitter 18 schedules both the traffic of the frame Add received from the RPR interface transmitter 12 and the transit of the received frame Transit, and based on the scheduling result, the received frame received from the outer ring drop determiner 17 and the RPR The frame received from the interface transmitter 12 is transmitted to the outer ring 7. The inner ring transmission unit 19 schedules both the traffic of the frame Add received from the RPR interface transmission unit 12 and the transit of the reception frame Transit, and based on the scheduling result, the received frame received from the inner ring drop determination unit 20 and the RPR The frame received from the interface transmitter 12 is transmitted to the inner ring 6.

In the present embodiment, the concentrator switch unit 11 is provided. However, even if the concentrator switch unit 11 is not provided, the present embodiment can be implemented by performing a change depending on the interface type of the relay link port as necessary. A similar operation can be realized with a configuration similar to that of the first embodiment.

Here, a topology map creation function, a ring failure detection function, a protection function, and a fairness function defined by RPR will be described.
(1) Understanding node order (topology map creation function)
Understand in what order the nodes are connected and configure a topology map at each node. Each node transmits a control frame called a TP (Topology and Protection) frame including TTL, which is a value subtracted by 1 every time it is relayed, to both rings (inner side and outer side) at a constant cycle. Each node grasps the position (number of relays of the node) of the TP frame transmission node as seen from its own node based on the TTL included in the received TP frame, and creates a topology map. When a node other than the transmitting node receives a TP frame, the TTL included in the frame is subtracted and relayed as a TP frame including the value after the subtraction as a TTL, and finally terminated at the transmitting node (the transmitting node is Discard it yourself).

(2) Detection and publicity of ring faults between adjacent nodes (ring fault detection function)
When each node transmits the TP frame to both rings, it does not reach the KeepAlive frame (Single Choke Fairness frame for fairness control: SCFF frame) and receives itself from the immediately upstream node (upstream adjacent node) Based on the failure, a failure is detected between the links from the immediately upstream node to the own node. Whether the KeepAlive frame transmission source is the immediate upstream node is determined based on the topology map of (1). Information on the failure (link state information) between the link from the immediately upstream node to the own node is sent on the TP frame, and all receiving nodes including the immediately downstream node (downstream adjacent node) Based on the information, the link state of the TP frame transmission source node is grasped, and which link on the ring is in a failure state (ring failure information) is mapped.

(3) RPR data frame transmission direction switching (protection function)
Normally, each node selects a ring with a small number of node relays and no link failure before reaching the destination node based on the topology map of (1) and the ring failure information of (2). Send a data frame.

(4) Fair use of ring transmission bandwidth (fairness function)
Each node periodically transmits the above-mentioned SCFF frame. In this frame, an add rate (here, the amount of data that can be transmitted per unit time determined based on the downstream node side and its own congestion state) The best-effort traffic add rate) and a congestion detection node address (or its own address if it is determined that congestion has occurred) are transmitted to the immediately upstream node. The node that has received the SCFF frame sets the add rate based on the congestion state on the downstream node side based on the congestion information (add rate, congestion detection node address, etc.) for fairness control included in the received frame and its own congestion state. decide. Then, the SCFF frame including the determined add rate is transmitted to the immediately upstream node. In this way, congestion information for fairness control is notified in the upstream direction in order, and each node suppresses transmission according to the add rate of the received SCFF frame. This eliminates the unfairness of the best-effort bandwidth resource and provides bandwidth fairness among the nodes.

Although the RPR standard functions described above can achieve failure avoidance and load distribution in the ring network, load distribution cannot be realized for data passing through a relay link connecting the ring networks. A multi-ring network system generally includes a plurality of relay links, and the use efficiency of the band can be improved by performing load distribution on these relay links. Therefore, in the present embodiment, the load distribution of the relay link is realized by performing the operation described below.

Next, the load distribution method of this embodiment in each communication state will be described. FIG. 3 is a configuration diagram of a multi-ring network system for explaining an operation example in a normal state. The configuration of the multi-ring network system of FIG. 3 is the same as that of FIG. 2, and further, a terminal 8-1 is connected to the RPR ring node device 1-5, and a terminal 8-2 is connected to the RPR ring node device 1-4. It is connected. In such a configuration, when the terminal 8-1 and the terminal 8-2 perform communication, it is necessary to transmit and receive data between networks using a relay link connecting the network 2 and the network 3.

Here, the relay link connected by the RPR ring node device 1-2 and the RPR ring node device 1-6 that are West pair link nodes, and the RPR ring node device 1-3 and the RPR ring node device that are East pair link nodes It is assumed that two relay links, that is, the relay link connected by 1-7, can be used. Also, in FIG. 3, data flow # 1 and data flow # 2, which are two types of data flows when the terminal 8-1 transmits data to the terminal 8-2, are shown as a solid line arrow and a one-dot chain line arrow, respectively. ing.

The data flow # 1 indicated by the solid line passes through the East relay link 5 connected by the East pair node, and the data flow # 2 indicated by the solid line passes through the West relay link 4 connected by the West pair node. In this way, the data flow addressed to the terminal 8-2 transmitted from the terminal 8-1 is relayed from the network 3 to the network 2 by the West relay link 4 or the East relay link 5. This data flow is added by a pair node (West pair node or East pair node) on the network 2 side connected to the relay link through which the data flow is sent to the network 2 and reaches the terminal 8-2.

Note that it is assumed that each data flow is transmitted by multicast, and each flow is always broadcast to all devices on the ring network. Although the description of unicast communication is omitted, the operation of the present embodiment can be similarly applied to unicast communication.

For each data flow, there are various methods for selecting which relay link to select as a relay link to be used for relaying. Any method can be selected so as not to be biased toward a specific relay link. Such a method may be used.

Next, the RPR ring node device 1-5 connected to the terminal 8-1 on the transmission side, the pair nodes 1-6, 1-7 on the network 3, the pair nodes 1-2, 1-3 on the network 2, and the reception side The operation of the RPR ring node device 1-4 connected to the terminal 8-2 will be described.

First, the operation of the RPR ring node device 1-5 (the RPR ring node device on the frame transmission side) connected to the terminal 8-1 on the transmission side will be described. When the RPR ring node apparatus 1-5 recognizes the usable relay link based on the multi-ring information and determines that a plurality of relay links can be used, the RPR ring node apparatus 1-5 Determine the end node. For example, for data flow # 1, the relay link to be used is determined as the East relay link 5, and the terminal node is determined as the East pair node on the network 3 side. For this determination, for example, a relay link is selected for each data flow based on a predetermined selection method, and the selection result is held by the RPR ring node device 1-5 as relay link selection information. The relay link to be used corresponding to each data flow is determined. This process is performed by the RPR interface transmitter 12 in the configuration example of FIG.

Then, when receiving the frame from the terminal 8-1, the RPR ring node device 1-5 extracts information for identifying the data flow from the received frame, and based on the extracted information, the RPR ring node device 1-5 is the frame of the data flow # 1. When the determination is made, the East pair node (in this case, the RPR ring node apparatus 1-7) is set as a termination node, and the frame after setting is added by Flooding. In this case, the RPR ring node device 1-5 is adjacent to the RPR ring node device 1-6 that is the West pair node in the network 2, but it is not necessary to make the data flow # 1 arrive at the West pair node. The frame is not transmitted in the direction (outer ring) toward the RPR ring node apparatus 1-6, but is transmitted to the inner ring. Therefore, it is added not by Bi-Directional Flooding but by Uni-Directional Flooding.

Also, when the RPR ring node apparatus 1-5 receives the frame of the data flow # 2 from the terminal 8-1, it extracts a predetermined part in the received frame and recognizes that it is the frame of the data flow # 2. A relay link is selected based on the held relay link selection information, the corresponding West pair node is set as a termination node, and the set frame is added to the outer ring by Flooding. Since data flow # 2 does not need to arrive at the East pair node, when adding to the inner ring (in the direction of the RPR ring node device 1-8), the East pair node (in this case, the RPR ring node device 1-7) Add the immediate upstream node (in this case, the RPR ring node device 1-8) as a termination node. In this case, Bi-Directional Flooding is used. In this way, the RPR ring node device 1-5 determines the end node based on the relay link (use relay link) that uses the end node for relaying the frame of the data flow and the network structure. Specifically, in the ring in the direction in which the frame is transmitted to the pair node connected to the used relay link, the pair node connected to the used relay link is a termination node, and in the other direction ring, the frame arrives based on the network configuration. A terminal node is determined in consideration of unnecessary node devices.

Specifically, in the configuration example of FIG. 1, the RPR interface transmission unit 12 of the RPR ring node device 1-5 searches for a predetermined location in the frame of the data flows # 1 and # 2 received via the line concentration SW unit 11. After the extraction, the terminal node is set, and the set frame is output to the inner ring transmission unit 19 or the outer ring transmission unit 18. Then, the inner ring transmission unit 19 or the outer ring transmission unit 18 adds the frame and sends it to the inner ring or the outer ring. Similarly, in the subsequent processing, the RPR interface transmission unit 12 performs processing such as determination of the relay link and the termination node, and the inner ring transmission unit 19 or the outer ring transmission unit 18 transmits the frame Add to the ring. We will send it.

Next, operations of the RPR ring node device 1-6 and the RPR ring node device 1-7, which are pair nodes (West pair node, East pair node) in the network 3, will be described. When the RPR ring node device 1-6 and the RPR ring node device 1-7 receive the frames of the data flows # 2 and # 1, respectively, from the inner ring or the outer ring, the frames are frames having themselves as termination nodes. In this case, the frame is dropped and transferred to the relay link to which the frame is connected.

Specifically, in the configuration example of FIG. 1, the outer ring drop determination unit 17 and the inner ring drop determination unit 20 of the RPR ring node devices 1-6 and 7 are respectively transmitted via the outer ring reception unit 16 and the inner ring reception unit 21. When the frame of the data flow # 2 or # 1 is received and is a frame having itself as a termination node, the frame is dropped and output to the RPR interface receiving unit 13, and the RPR interface receiving unit 13 11 to the relay link. The outer ring drop determination unit 17 and the inner ring drop determination unit 20 output the received frame to the outer ring transmission unit 18 and the inner ring transmission unit 19 when not dropping. Similarly, in the subsequent processing, the outer ring drop determination unit 17 and the inner ring drop determination unit 20 perform the drop processing and the output of the RPR interface reception unit 13, and the RPR interface reception unit 13 performs transfer to the relay link. I will do it.

Next, operations of the RPR ring node device 1-2 and the RPR ring node device 1-3 which are pair nodes (West pair node, East pair node) in the network 2 will be described. The RPR ring node device 1-2 and RPR ring node device 1-3 use a normal RPR transmission process to send a frame arriving from a relay link to which the RPR ring node device 1-2 and RPR ring node device 1-3 are connected (a frame transferred from a partner pair node in the network 3) to Bi. -Send with Directional Flooding.

Also, the RPR ring node device 1-2 and RPR ring node device 1-3, when the frame is received by the inner ring or the outer ring, the source is the MAC address of another pair node in the network to which it belongs. Even a multicast frame is not dropped and is not transferred to the relay link (non-transfer frame 30 in FIG. 3).

Then, the RPR ring node device 1-4 connected to the terminal 8-2 receives the data flow # 1 via the East relay link and the data flow # 2 via the West relay link from the outer ring or the inner ring, By a normal RPR reception process, the reception frame of each data flow is dropped and transferred to the terminal 8-2.

Next, the operation when a failure occurs in the link between the RPR ring node device 1-6 and the RPR ring node device 1-7 in the network 3 will be described. FIG. 4 is a diagram for explaining the operation when a failure occurs according to the present embodiment. First, it is assumed that a failure 31 has occurred in the RPR ring node device 1-6 and the RPR ring node device 1-7 from the state where the communication as shown in FIG. 3 was performed, as shown in FIG.

When the RPR ring node device 1-5 connected to the terminal 8-1 recognizes a usable relay link based on the multi-ring information and determines that a plurality of relay links can be used, as in the normal state. In this case, the relay link and terminal node to be used are determined for each data flow.

When receiving the frame of data flow # 1 from the terminal 8-1, the RPR ring node device 1-5 sets the East pair node as a termination node and adds the set frame by Flooding as in the normal state.

Also, when the RPR ring node device 1-5 receives the frame of the data flow # 2 from the terminal 8-1 as in the normal state, the RPR ring node device 1-5 extracts a predetermined portion in the received frame and then terminates the West pair node. It is set as a node, and the frame after setting is added by Flooding. Then, the RPR ring node device 1-5 detects the failure location by the failure detection function of RPR, and determines that the route to the West pair node (RPR ring node device 1-6) needs to be switched. In this case, it is determined that the frame of the data flow # 2 is added only to the inner ring (in the direction of the RPR ring node device 1-8), and the frame having the terminal node as the West pair node is added only to the inner ring. In this case, it is added by Uni-Directional Flooding.

The RPR ring node device 1-7 that is the East pair node in the network 2 receives both frames of the data flow # 1 and the data flow # 2. When receiving the frame of data flow # 1, the RPR ring node device 1-7 drops the frame and transfers it to the relay link to which the RPR ring node device 1-7 is connected, as in the normal state. On the other hand, when the RPR ring node apparatus 1-7 receives the frame of the data flow # 2, the RPR ring node apparatus 1-7 does not drop because it is not a terminal node, performs only Transit, does not transfer to the relay link to which it is connected, and Relay towards the node.

When the RPR ring node device 1-6, which is the West pair node in the network 2, receives the frame of the data flow # 2 relayed by the RPR ring node device 1-7 by Transit, it drops the frame because it is a terminal node. Forward to the relay link to which it connects.

The operation of the RPR ring node device 1-4 connected to the pair node in the network 3 and the terminal 8-2 is the same as that in the normal state of FIG. With the above operation, if multiple relay links are used and a failure occurs in the route to one of the relay links, data can be transmitted from the reverse ring to that relay link. The number of relay links to be used can be maintained.

When the RPR ring node device connected to the terminal that transmits data determines that there is one relay link that can be used based on the multi-ring information, the RPR ring node device can be used without being distributed in units of flows. The frame is added using the pair node connected to the relay link as a termination node.

In this embodiment, the case where there are two relay links has been described. However, even when there are three or more relay links, a relay link is selected for each data flow, and this is handled for each data flow. By setting the end node, load distribution of the relay link can be performed.

As described above, in the present embodiment, in the multi-ring network, the RPR ring node device node on the frame transmission side uses the relay link of the flow for each data flow from among the usable relay links. A relay link is selected, and a pair node connected to the relay link is set as a termination node for each flow, and a frame is transmitted to the ring network. The pair node then forwards the frame set as the end node to the relay link to which the pair node is connected, and the frame to which the other pair node of the ring network to which the pair node belongs is connected is connected to the pair node. Do not forward to link. Therefore, it is possible to use a plurality of relay links while avoiding a traffic flow loop, and it is possible to improve bandwidth utilization efficiency by load distribution.

Embodiment 2. FIG.
FIG. 5 is a diagram illustrating a functional configuration example of the second embodiment of the RPR ring node device according to the present invention. As shown in FIG. 1, the RPR ring node device 1a according to the present embodiment includes an RPR interface transmission unit 12 and an RPR interface reception unit 13 of the RPR ring node device 1 according to the first embodiment, respectively. The RPR ring node device 1 of the first embodiment is the same as the RPR ring node device 1 of the first embodiment except that a reception flow filtering unit 24 is added instead of the interface reception unit 13a. Components having the same functions as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and description thereof is omitted.

The RPR interface reception unit 13a of the present embodiment has the same function as the RPR interface reception unit 13 of the first embodiment, and can be used based on multiring information when the RPR interface reception unit 13a is a pair node. When the received frame dropped (received frame received from the outer ring determination unit 17 or the inner ring drop determination unit 20) is a data flow frame passing through the relay link, it is set and retained in each pair node in advance. In accordance with the flow identification rule, predetermined data for identifying the flow is extracted from the dropped received frame and notified to the reception flow filtering unit 24 as flow identification information. Further, when the RPR interface receiving unit 13a is a pair node, the RPR interface receiving unit 13a receives a notification of whether the relay link can pass or not from the reception flow filtering unit 24. If it does not pass, it is discarded.

When receiving the flow information notification from the RPR interface receiving unit 13a, the reception flow filtering unit 24 searches a management table that is a pre-stored information for identifying a flow that is permitted to pass, and the received flow identification information and If there is no matching information as a result of the search, it is determined that the flow is not transferred to the relay link (relay pass / fail), and if there is matching information, the relay is performed. It is determined that the data is transferred to the link (passage through the relay link is possible), and the RPR interface reception unit 13a is notified of the determination result as to whether the relay link can pass through.

The RPR interface transmission unit 12 of the present embodiment does not perform the selection of the relay link and the setting of the termination node performed in the first embodiment, but otherwise is the same as the RPR interface transmission unit 12 of the first embodiment. It is.

Next, the load distribution method of this embodiment in each communication state will be described. FIG. 6 is a configuration diagram of a multi-ring network system for explaining an example of normal operation of the present embodiment. The configuration of the multi-ring network system of this embodiment is the same as that of Embodiment 1 except that RPR ring node devices 1-1 to 1-8 of Embodiment 1 are replaced with RPR ring node devices 1a-1 to 1a-8. This is the same as the ring network system. The RPR ring node devices 1a-1 to 1a-8 have the same configuration as that of the RPR ring node device 1a shown in FIG. The RPR ring node devices 1a-1 to 1a-4 constitute a ring network 2a, and the RPR ring node devices 1a-5 to 1a-8 constitute a ring network 3a.

As shown in FIG. 6, in the normal state, the relay link is the West relay link (the relay link connecting the RPR ring node device 1a-2 and the RPR ring node device 1a-6, which is the West pen node) and the East relay link (East pen node). Two relay links, ie, a relay link connecting a certain RPR ring node device 1a-3 and RPR ring node device 1a-7, can be used. In FIG. 6, data flow # 1 (solid arrow) and data flow # 2 (dashed line) are shown as the flow of data transmitted from the terminal 8-1. Further, in this embodiment, it is assumed that each data flow is transmitted by multicast as in the first embodiment, and each flow is always broadcast on all ring networks. Although the description of unicast communication is omitted, the operation of the present embodiment can be similarly applied to unicast communication.

In addition, there are various methods for selecting a relay link to select which relay link for each data flow. However, as in the first embodiment, if the selection is not biased to a specific relay link, there is a problem. Absent. It is assumed that each West pair node holds a management table having the same contents. In addition, it is assumed that the East pair nodes respectively hold management tables having the same contents. This management table selects information for selecting a relay link based on the relay link selection method for each data flow, and identifying the data flow to be passed for each relay link based on the correspondence between the selected data flow and the relay link. Is a table storing Each pair node holds a management table in which information for identifying a data flow to be passed by a relay link to which the pair node is connected is stored. Therefore, the management tables held by the West pair node and the East pair node are different from each other. In the example of FIG. 6, it is assumed that the management table of the West pair node includes information (flow identification information) for identifying the data flow # 1, and the management table of the East pair node includes the flow identification information of the data flow # 2. Let's say.

First, frames of each data flow received from the terminal 8-1 are added to the bi-directional ring by Bi-Directional Flooding according to normal RPR transmission processing.

The pair nodes (East pair node, West pair node) in the ring network 3a determine whether there are a plurality of usable relay links based on the multi-ring information, and if there are a plurality of usable relay links, for each data flow, Determine whether the flow passes through the relay link. When it is determined that the number of usable relay links is one (relay link to which the self is connected), the relay link is transferred to the relay link to which the self is connected regardless of the data flow.

Specifically, the pair node in the ring network 3a extracts the flow identification information from the frame of each data flow, and searches the management table using the above flow identification information as a key. As a result of the search, if there is information matching the flow identification information in the management table, the frame of the data frame is transferred to the relay link to which it is connected. If there is no information matching the flow identification information in the management table, the frame of the data frame is not transferred to the relay link to which it is connected. In the example of FIG. 6, the West pair node transfers the frame of the data flow # 1 to the West relay link, and does not transfer the frame of the data flow # 2 to the West relay link (non-transfer frame 32 in FIG. 6). Further, the East pair node transfers the frame East of the data flow # 2 to the relay link, and does not transfer the frame of the data flow # 1 to the East relay link (non-passing data flow 32 in FIG. 6).

Next, the pair node in the ring network 2a that has received the frames of the data flows # 1 and # 2 from the relay link to which it is connected transmits the frame received by the normal RPR transmission process by Bi-Directional Flooding.

The West pair node in the ring network 2a receives the data flow # 1 frame. At this time, the West pair node in the network 2a matches the flow identification information of the data flow # 1 even if the management table is searched. Because there is no, it is not transferred to the West relay link. Further, the East pair node in the network 2a receives the frame of the data flow # 2, but at this time, the East pair node in the network 2a matches the flow identification information of the data flow # 2 even if the management table is searched. Since there is no information, it is not transferred to the East relay link. With the above operation, the data flow transferred from the ring network 3a to the ring network 2a does not return to the ring network 3a again.

Then, the RPR ring node device 1a-4 connected to the terminal 8-2 drops the frames of the data flows # 1 and # 2 by normal RPR reception processing and transfers the frames to the terminal 8-2.

Next, an operation when a failure occurs in the link between the RPR ring node device 1a-6 and the RPR ring node device 1a-7 in the network 3a will be described. FIG. 7 is a diagram for explaining the operation when a failure occurs according to the present embodiment. First, it is assumed that a failure 33 has occurred in the link between the RPR ring node device 1a-6 and the RPR ring node device 1a-7 as shown in FIG. To do.

The terminal 8-1 detects the failure location by the failure detection function of the RPR, and determines that the route to the West pair node needs to be switched. In the example of FIG. 7, since there is a failure in the link of the outer ring to the West pair node, it is determined that the frame to reach the West pair node is Add to the inner ring, and the data flow # 1, # 2 Add a frame.

As in the normal state, the East pair node in the network 3a searches the management table for information that matches the flow identification information of the frame of each data flow. It is transferred to the relay link to which it is connected. If there is no matching information, it is not transferred to the relay link. In the case of FIG. 7, the frame of the data flow # 1 is dropped and the frame is transferred to the relay link to which the frame is connected. Further, when there is no matching information in the management table, the East pair node performs only Transit on the received frame and relays it toward the downstream node. In the case of FIG. 7, the frame of the data flow # 2 is not transferred to the relay link, and only the transit is performed and relayed to the downstream node.

As in the normal state, the West pair node in the network 3a searches the management table for information that matches the flow identification information of each data flow frame, and if there is matching information, It is transferred to the relay link to which it is connected. If there is no matching information, it is not transferred to the relay link. In the example of FIG. 7, the West pair node in the network 3a does not drop the frame of the data flow # 1 and does not transfer it to the relay link. Also, the West pair node in the network 3a drops the frame of the data flow # 2 and transfers it to the West relay link.

The pair node in the network 2a transmits the frame arriving from the relay link to which the pair node in the network 2a is connected by Bi-Directional Flooding by the normal RPR transmission processing. Of the frames received by each pair node, the frame of the data flow # 1 passes through the West pair node in the network 2a, but the West pair node in the network 2a matches even if the management table is searched for the data flow # 1. Since there is no information to be transferred, it is not transferred to the West relay link. The data flow # 2 passes through the East pair node in the network 2a, but the East pair node in the network 2a has no matching information even if the management table is searched for the data flow # 2, so the East relay link Do not forward to.

Then, the RPR ring node device 1a-4 connected to the terminal 8-2 drops the frames of the data flows # 1 and # 2 by the normal RPR reception process and transfers them to the terminal 8-2 as in the normal state. .

If it is determined from the multi-ring information that there is only one relay link, it is not determined whether or not the relay link can be passed for each data flow, and the pair node connected to the usable relay link relays. Forward the flow to the link.

As described above, in the present embodiment, when a plurality of relay links can be used in a multi-ring network, a relay link that relays the data flow is defined in advance for each data flow, and each pair node Data flow identification information is stored as a management table, and when a data flow frame included in the management table is received, the frame is transferred to the relay link to which it is connected, and the data flow is not included in the management table When a frame is received, it is not transferred to the relay link. Therefore, it is possible to use a plurality of relay links while avoiding a traffic flow loop, and it is possible to improve bandwidth utilization efficiency by load distribution.

Furthermore, in the present embodiment, it is sufficient that only the pair node can acquire the multi-ring information, and nodes other than the pair node may be single-ring compatible nodes, and the system configuration can be simplified.

As described above, the multi-ring network system, the ring node device, and the load distribution method according to the present invention are useful for a multi-ring network system, and are particularly suitable for a multi-ring network system including a plurality of relay links.

Claims (11)

A plurality of ring networks are provided, and at least one of the ring node devices constituting the ring network is a pair node, and is transmitted / received between different ring networks via a relay link that is a link connecting a pair of pair nodes. A multi-ring network system that relays data as relay data,
Provide a plurality of the relay links,
The ring node device of the frame transmission source selects a relay link to be used for relaying the data flow for each data flow, holds the correspondence between the data flow and the selected relay link, and is included in the frame to be transmitted. A relay link corresponding to the identification information of the data flow is determined based on the correspondence, and a pair node connected to the determined relay link in the own ring network that is a ring network to which the data flow belongs is set as a terminal node of the frame. , Send the frame to its own ring network,
When the terminal node of the frame received from the own ring network is the own node, the pair node transfers the received frame as relay data to the relay link to which the pair node is connected, and relay data from the relay link to which the pair node is connected. A multi-ring network system, wherein the relay data is transmitted to the self-ring network using itself as a transmission source. 2. The multi-ring according to claim 1, wherein when the pair node receives a frame whose source is another pair node in the self-ring network, the pair node does not transfer the frame to a relay link to which the pair node is connected. Network system. The ring node device that is the transmission source of the frame grasps the number of usable relay links based on the multi-ring information that is failure information of the relay link and the pair node, and when the number of usable relay links is one The frame nodes of all data flows are set as paired nodes in the own ring network corresponding to usable relay links as termination nodes, and the frames are transmitted to the own ring network. Multi-ring network system. The ring node device that is the transmission source of the frame grasps the number of usable relay links based on the multi-ring information that is failure information of the relay link and the pair node, and when the number of usable relay links is one The frame node of all data flows is set as a termination node in a pair node in the own ring network corresponding to an available relay link, and the frame is transmitted to the own ring network. Multi-ring network system. A plurality of ring networks are provided, and at least one of the ring node devices constituting the ring network is a pair node, and is transmitted / received between different ring networks via a relay link that is a link connecting a pair of pair nodes. A multi-ring network system that relays data as relay data,
Provide a plurality of the relay links,
The pair node is identification information of a data flow using a relay link to which the pair node is connected, which is generated based on a correspondence between a data flow and a relay link selected in advance as a relay link used for relaying the data flow. Holds passing data flow information, and if the passing data flow information includes information that matches the identification information of the data flow included in the received frame, the frame is transferred as relay data to the relay link to which the frame is connected. A multi-ring network system characterized in that, when relay data is received from a relay link to which it is connected, the relay data is transmitted to the own ring network using itself as a transmission source. The ring network uses the RPR protocol,
The ring node device that is a frame transmission source, when detecting a failure based on a failure detection function of the RPR protocol, changes a route in the own ring network of a frame to be transmitted. The multi-ring network system according to any one of 5. A plurality of ring networks are provided, and at least one of the ring node devices constituting the ring network is a pair node, and is transmitted / received between different ring networks via a relay link that is a link connecting a pair of pair nodes. In a multi-ring network system for relaying data as relay data, a ring node device that functions as the pair node,
Passed data flow information that is identification information of a data flow that uses a relay link to which the data flow is connected, generated based on the correspondence between the data flow and the relay link selected as a relay link to be used for relaying the data flow in advance. Receiving flow filtering means for determining whether or not the received frame can pass based on whether or not the passing data flow information includes information that matches the identification information of the data flow included in the received frame;
A ring interface receiving means for transferring the frame as relay data to a relay link to which the frame is connected when the result of the determination is acceptable;
When the relay data is received from the relay link to which it is connected, the ring interface transmission means for transmitting the relay data to the own ring network using itself as a transmission source;
A ring node device comprising: 8. The ring interface receiving unit according to claim 7, wherein when receiving a frame having a transmission source from another pair node in the own ring network, the ring interface receiving unit does not transfer the frame to a relay link to which the ring interface receiving unit is connected. Ring node equipment. The ring interface receiving means grasps the number of usable relay links based on the multi-ring information which is failure information of the relay link and the pair node, the number of usable relay links is one, and the relay link The ring node apparatus according to claim 7 or 8, wherein, when a relay link is connected to itself, frames of all data flows are transferred as relay data to the relay link to which the terminal is connected. A plurality of ring networks are provided, and at least one of the ring node devices constituting the ring network is a pair node, and is transmitted / received between different ring networks via a relay link that is a link connecting a pair of pair nodes. Load distribution method in a multi-ring network system that relays data as relay data,
Provide a plurality of the relay links,
A ring node device that is a transmission source of a frame selects a relay link to be used for relaying the data flow for each data flow, and maintains a correspondence between the data flow and the selected relay link.
The ring node device that is the transmission source of the frame determines the relay link corresponding to the identification information of the data flow included in the frame to be transmitted based on the correspondence, and the determination in the own ring network that is the ring network to which the frame node belongs is determined. A pair node connected to the relay link is set as a terminal node of the frame, and a terminal node setting step of sending the frame to the own ring network;
A relay data transfer step for transferring the received frame as relay data to a relay link to which the pair node is connected to itself when a terminal node of the frame received from the own ring network is the own node;
When the pair node receives relay data from a relay link to which the pair node is connected, the relay data is transmitted to the own ring network using the relay data as a transmission source;
A load balancing method comprising: A plurality of ring networks are provided, and at least one of the ring node devices constituting the ring network is a pair node, and is transmitted / received between different ring networks via a relay link that is a link connecting a pair of pair nodes. Load distribution method in a ring node device functioning as the pair node in a multi-ring network system that relays data as relay data,
Passed data flow information that is identification information of a data flow that uses a relay link to which the data flow is connected, generated based on the correspondence between the data flow and the relay link selected as a relay link to be used for relaying the data flow in advance. A passing data flow holding step for holding
A reception flow filtering step of determining whether or not the received frame can be passed based on whether or not the passing data flow information includes information that matches the identification information of the data flow included in the received frame;
A ring interface receiving step of transferring the frame as relay data to a relay link to which the frame is connected when the result of the determination is acceptable;
When the relay data is received from the relay link to which it connects, the ring interface transmission step of transmitting the relay data to the own ring network using itself as a transmission source;
A load balancing method comprising:

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