JP4530697B2 - Communications system - Google Patents

Description

  The present invention relates to a communication system, and more particularly to a communication system that performs communication by performing routing processing on a network.

  In recent years, the communication network represented by the Internet has been greatly increased in capacity and widened, and the number of communication devices (NE: network entities) managed by a communication carrier constituting a backbone network has increased. It has become.

  When used in a management network (OSI network) compliant with OSI (Open Systems Interconnection: 7-layer network protocol structure model) defined by international standards ISO9542 and ISO10589, NE Point) It is determined to be uniquely identified using an address (in ATM networks, ATM addresses are used to identify nodes, but in the same way, on SAPI networks, NSAPs are used to identify nodes). Address is used).

  In this case, the NE is managed and controlled on the OSI network independent of the network through which user traffic flows. The NSAP address is defined in ISO (International Organization for Standardization) / IEC (Inter-Exchange Carrier) 8348: 1996 Annex.A.

  The NE when the OSI network is configured is called a network node (or simply a node). Particularly, a node such as a user computer that does not have a routing function on the OSI network is an ES (End System), a relay having a routing function. The node is called IS (Intermediate System).

  The OSI network employs a method of managing the entire network (domain) by dividing it into a plurality of areas, and operates by dividing routing within the area as Level 1 (L1 routing) and routing between areas as Level 2 (L2 routing). It is structured.

  FIG. 13 is a diagram showing domains and areas. In the figure, IS1 is a node having an L1 routing function, and IS1IS2 is a node having both L1 and L2 routing functions. A thick solid line indicates an L1 connection in the area (connection line for performing L1 routing), and a dotted line indicates an L2 connection between the areas (connection line for performing L2 routing).

  The domain 100 is divided into areas 110 and 120. In the area 110, the ES nodes 111 to 114 and the IS1 nodes 115 and 117 are L1 connected in a bus shape, the IS1 nodes 115 and 116 are L1 connected, and the IS1 node 117, the IS1IS2 node 118, and the ES node 114 are L1 connected. .

  In the area 120, the IS1IS2 node 121 and the IS1 node 122 and the IS1IS2 node 124 are L1 connected, and the IS1 node 122 and the ES node 123 are L1 connected. Then, the IS1IS2 node 118 in the area 110 and the IS1IS2 node 121 and the IS1IS2 node 124 in the area 120 are L2 connected. That is, the IS1IS2 nodes perform L2 connection simultaneously with L1 connection.

  Here, a node having the L1 routing function requires information on all network nodes existing in the area, based on the OSI protocol. Therefore, when a network node is added to a certain area, the memory resources and processing performance resources of all the nodes in the area are affected.

  In addition, when adding a node to an area, only the number of nodes that can operate the node having the poorest resource in the area (for example, there is a network whose upper limit is 300 nodes) can be connected to the area. . This is because if a node is added and a resource of a certain NE is insufficient, network operation including that NE cannot be guaranteed.

  This can be said in other words that there is an upper limit on the number of NSAP addresses included in a certain area, since nodes on the network are uniquely identified by NSAP addresses and managed in units.

  The same applies to L2 routing. Since a node that performs L2 routing needs to have routing information of all network nodes that perform L2 routing, the number of nodes having the L2 protocol (or the number of NSAP addresses) is limited. There is.

  Since the number of nodes connected to the OSI network is increasing, it can be considered from the above that the NSAP address is becoming an important resource on the network.

As a conventional technique related to NSAP addresses, a technique for detecting duplication of NSAP addresses assigned to data transmission apparatuses has been proposed for data transmission apparatuses existing in the entire interconnected network (for example, patents). Reference 1).
Japanese Patent Laid-Open No. 11-112548 (paragraph numbers [0023] to [0032], FIG. 1)

  Conventionally, when increasing the user line capacity of SONET / SDH (Synchronous Optical Network / Synchronous Digital Hierarchy) network (hereinafter referred to as SONET network) (increasing the number of lines), simply add NE or remove existing NE The method of replacing with a large capacity was taken.

  FIG. 14 is a diagram showing an example of capacity expansion of a conventional SONET network. When the capacity of the network state A1 is increased, NE is added and the network state A2 is shown.

  The network state A1 includes IS1 nodes 51 to 53, the IS1 node 51 is connected to the IS1 nodes 52 and 53 via the OSI network 32, and the IS1 nodes 52 and 53 are connected to the SONET network 31.

  In the network state A2, on the OSI network 32, the IS1 node 54 is additionally connected to the IS1 node 52, the IS1 node 55 is additionally connected to the IS1 node 53, and the IS1 nodes 54 and 55 are connected to the SONET network 31.

  In the case of adding NEs in this way, in order to operate management control normally in the entire OSI network, the above-mentioned prior art (Japanese Patent Laid-Open No. 11-112548) etc. is used to make sure that the NSAP does not overlap with existing nodes. It was necessary to assign addresses to the added nodes (IS1 nodes 54 and 55).

  However, the conventional capacity expansion method by NE expansion has a problem that even if NSAP addresses are assigned so as not to overlap, consumption of the NSAP addresses cannot be suppressed.

  FIG. 15 is a diagram showing an example of capacity expansion of a conventional SONET network. When the capacity of the network state A1 is increased, the existing NE is replaced with the large-capacity NE to enter the network state A3.

  The network state A3 includes IS1 nodes 51, 62, and 63. The IS1 node 51 is connected to the IS1 nodes 62 and 63, which are new high-capacity NEs, via the OSI network 32. The IS1 nodes 62 and 63 are connected to the SONET network 31. Connect with.

  In this way, when replacing an existing NE with a large-capacity NE, the NSAP address of the existing NE can be used for the NE after the replacement, so that the NSAP address is not consumed before the capacity expansion. However, the cost of purchasing a large-capacity device is higher than the total of the small-capacity devices for the same capacity, and the existing NE equipment is wasted, resulting in significant costs and low operability. There was a problem.

  The present invention has been made in view of these points, and an object of the present invention is to provide a communication system in which a capacity is increased and routing processing is performed without consuming an NSAP address.

In order to solve the above problems, a communication system is provided. The communication system is connected to a user network in which user traffic flows and a management network in which management control information including routing data and control data flows, and is uniquely identified on the management network by a specific address, A first transmission device that communicates by generating a virtual node having one specific address by connecting to another device via an internal network independent of each management network, and the first transmission device via the internal network A second transmission device that connects to one transmission device, generates the virtual node, and communicates on the management network while sharing the same specific address as the first transmission device.

  Here, if the received management control information is routing data, the second transmission device transfers the routing data to the first transmission device through the internal network. If the received management control information is control data, It is determined whether or not the control data is the target data for the routing process in the own device. If the control data is the target data, the routing process is performed and the control data is connected to the own device without going through the first transmission device. If the target data is transferred from the management network, it is transferred to the first transmission device through the internal network.

Communication system, the primary transmission device that is uniquely identified by a specific address on the managed network, upon volume expansion, through a separate internal network and user network and the management network respectively connected to the additionally provided device virtualization Create a node. Then, when the capacity is increased, the sub transmission device is connected to the main transmission device via the internal network to generate a virtual node, and communicates by sharing the same specific address as the main transmission device on the management network. . As a result, even when the capacity is increased, the routing process can be efficiently performed without consuming the resource of the specific address. In addition, it is possible to reduce the load of the routing processing of the other device constituting the virtual node.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Figure 1 is a principle diagram of a communication system. The communication system 1 includes a main transmission device 10 and a sub-transmission device 20, and is a system that performs communication by performing routing processing on a network.

  The main transmission apparatus 10 is connected to a user network 31 (broken line in the figure) through which user traffic flows and a management network 32 (bold solid line in the figure) through which management control information including routing data and control data flows.

  The main transmission apparatus 10 is uniquely identified on the management network 32 by a specific address. When capacity is increased (number of lines is increased), the main transmission apparatus 10 is connected via an internal network 33 (dotted line in the figure) independent of the user network 31 and the management network 32. The virtual node 40 is generated by connecting to the added device (sub-transmission device) 20 to perform communication.

  When the capacity is increased, the sub-transmission apparatus 20 is connected to the main transmission apparatus 10 via the internal network 33 to generate a virtual node 40, and communicates on the management network 32 by sharing the same specific address as the main transmission apparatus 10. Do.

  Hereinafter, the user network 31 is referred to as a SONET network 31, and the management network 32 is referred to as an OSI network 32. Further, the description will be made with an NSAP address as a specific address.

  Furthermore, the routing data flowing through the OSI network 32 is packet data including information necessary for routing, and corresponds to, for example, a HELLO packet or an LSP (Link State Packet). Furthermore, the control data is data for performing NE monitoring control, and corresponds to, for example, a network management command such as TL1 (Transaction Language 1).

Next, additional capacity examples of S ONET network 31 will be described with reference to FIG. In the state before the capacity expansion, the IS1 nodes 10 a and 10 b having the function of the main transmission apparatus 10 are connected to the OSI network 32 and are connected to each other by the SONET network 31.

When performing capacity expansion, to the IS1 node 10a, SONET network 31 and separate OSI network 32 both in the internal network 33a is a communication channel capable of exchanging information between NE (user data and management control information) The NE 40a is generated as a virtual node by connecting to the IS1 node 20a having the function of the sub- transmission device 20.

Similarly, IS1 node 10b having the function of the main transmission device 10, the internal network 33b, connected to the IS1 node 20b having a function of sub-transmission device 20, generates a NE40b as a virtual node. In this way, the IS1 node 10a before capacity expansion is replaced with the virtual NE 40a, and the IS1 node 10b is replaced with the virtual NE 40b.

  Here, the IS1 node 10a is uniquely identified by the NSAP address (referred to as # 1) on the OSI network 32, and the IS1 node 20a added to the IS1 node 10a is the same as the IS1 node 10a via the internal network 33a. Communication is performed by sharing the NSAP address # 1.

  For this reason, the NSAP address of the virtual NE 40a after capacity expansion is the same as the NSAP address of the IS1 node 10a before capacity expansion, and is one NSAP address # 1 when viewed from the OSI network 32. There is no need to assign an NSAP address.

  Similarly, if the NSAP address of the IS1 node 10b is # 2, the NSAP address of the virtual NE 40b after expansion is also # 2, and the NSAP address # 2 of the IS1 node 10b before capacity expansion can be used as it is.

Thus, at the time of capacity expansion, connecting the NE by an internal network 33, by exchanging OSI protocol information (management control information) and user data, management of multiple NE at the same NSAP addresses, control to Is possible. In addition , the main transmission apparatus 10 and the sub transmission apparatus 20 are provided in an optical transmission apparatus such as SONET / SDH, thereby improving the function of the OSI network 32 used for monitoring control and being able to be accommodated in the same area. The number can be increased.

  In the above description, one sub-transmission device 20 is connected to one main transmission device 10 via one internal network 33, but a plurality of sub-transmissions are provided for one main transmission device 10. It is also possible to connect the devices 20 via a plurality of internal networks 33 and add them.

Next, the configuration of the main transmission apparatus 10 and the sub transmission apparatus 20 will be described. Hereinafter, the main transmission device is called Main NE, and the sub-transmission device is called Trib NE. FIG. 2 is a diagram showing a schematic configuration of the Main NE 10 .

  The Main NE 10 includes an internal network termination unit 11, a SONET termination unit 12, an OSI termination unit 13, a database management unit 14, a routing processing unit (main transmission side routing processing unit) 15, and a data processing unit 16.

  When the capacity is increased, the internal network termination unit 11 provides a connection interface with the added Trib NE 20 via the internal network 33 that is independent of the SONET network 31 and the OSI network 32.

The SONET termination unit 12 provides a connection interface for the SONET network 31, and the OSI termination unit 13 provides a connection interface for the OSI network 32.
The database management unit 14 manages three databases: an adjacency database 14a, an LSP database 14b, and a forwarding database (hereinafter referred to as a forwarding database) 14c. Hereinafter, an outline of each database will be described. The format configuration of each database is shown in FIGS. 5 to 7 (a plurality of data in the formats shown in FIGS. 5 to 7 are accumulated and each database is configured).

  The adjacency database 14a stores information related to all adjacent NEs on the same physical network as the own NE (here, the OSI network 32), and the HELLO packet (indicating that the function of the own device is alive) Is established based on the information received from the packet).

  The NE periodically transmits HELLO packets over the network. Since the HELLO packet reaches an adjacent NE on the same network, the NE knows that the response received by itself is a response from the adjacent NE. In the adjacency database 14a, for example, identification numbers (NE codes) and line numbers of all NEs connected to the own NE are stored.

The LSP database 14b stores routing information and network map information that can form a route from an end point to an end point for delivering a packet to a destination, and includes information stored in the LSP (Adjacency database 14a) and the NE link. It is a packet in which information and the like are described, and is established based on information received from all NEs in the area. The LSP database 14b, including the corresponding NE, that contains link information and the like of the neighboring NE in all NE on the network.

  The Forwarding database 14c is a database generated by collecting destination route information based on the information stored in the LSP database 14b (for example, using a shortest path search algorithm such as Dijkstra, It is generated from the calculation result). By using the Forwarding database 14c, it is possible to know the fastest route to the destination on the network.

On the other hand, the routing processing unit 15 in FIG. 2 performs routing processing of the received control data and SONET data. In the following described only the routing processing of the control data. Since the L1 routing and the L2 routing are the same procedure except that the operation data is replaced, only the L1 routing that is a routing process in the area will be described.

  The routing processing unit 15 receives control data through the OSI network 32 connected to itself (Main NE 10), or receives control data from the Trib NE 20 through the internal network 33. At this time, if it is determined that the routing process is to be performed, the destination is searched from the forwarding database 14c, and it is determined whether or not the Main NE code is written in the item corresponding to the same destination. Control data is transmitted from the corresponding line number of the device. When the Trib NE code is written, control data is transmitted to the Trib NE 20 via the internal network 33 (details of the routing process are shown in FIGS. 8 to 10 described later). If the data processing unit 16 determines that it is addressed to the own device when determining the routing of the control data, the data processing unit 16 performs a corresponding process of the command because it is a command addressed to the own device.

FIG. 3 is a diagram showing a schematic configuration of the Trib NE20 . The Trib NE 20 includes an internal network termination unit 21, a SONET termination unit 22, an OSI termination unit 23, a communication unit 24, and a data processing unit 25.

  When the capacity is increased, the internal network termination unit 21 provides a connection interface with the existing Main NE 10 via the internal network 33 that is independent of the SONET network 31 and the OSI network 32.

  The SONET termination unit 22 provides a connection interface for the SONET network 31, and the OSI termination unit 23 provides a connection interface for the OSI network 32. The communication unit 24 performs communication by sharing the same NSAP address as that of the Main NE 10 on the OSI network 32. The communication unit 24 basically transfers all received control data to the Main NE 10 via the internal network 33, and centrally manages routing processing in the Main NE 10 (control data returned from the Main NE 10). Is routed by Trib NE20). The data processing unit 25 is a block for processing control data (command) addressed to the own device.

  Next, a data format when the Trib NE 20 receives management control information from the OSI network 32 and transfers it to the Main NE 10 will be described. FIG. 4 is a diagram showing a format of transfer information. The Trib NE 20 transfers all management control information including routing data such as HELLO packets and LSPs and control data that are management commands received via the OSI network 32 to the Main NE 10 (not temporarily transferred to the Main NE 10 side). An embodiment that can be processed by the Trib NE 20 will be described later with reference to FIGS.

  In this case, when receiving the management control information through the OSI network 32, the Trib NE 20 adds the control code, NE code, line number, and data size to the management control information, generates transfer information 3, and transfers it to the Main NE 10.

  The control code is a code indicating that the data is received from the OSI network 32, and is fixed to 1. The NE code is a code indicating which NE of the Main NE 10 and the Trib NE 20 is received, and the Main NE 10 is 1 and the Trib NE 20 is 2 (here, it is 2 because it is received by the Trib NE 20). .

  The line number indicates the line number of the OSI network 32 in the Trib NE 20 that has received the management control information. The data size indicates the data size of the received management control information. These pieces of information are added to the management control information to form transfer information 3, which is transferred from the Trib NE 20 to the Main NE 10 via the internal network 33.

  Next, the configuration of the database will be described. When receiving the management control information directly received through the OSI network 32 or the management control information (transfer information 3) transmitted from the Trib NE 20 through the internal network 33, the Main NE 10 creates the databases shown in FIGS. .

  FIG. 5 is a diagram showing the configuration of the adjacency database 14a. The adjacency database 14a is a database that stores information on HELLO packets and collects adjacent NE information. Reserved, NE code, line number, and data size are HELLO PDU (Protocol Data Unit) data (payload data of HELLO packets). ) And saved.

  Reserved is fixed at 0, NE code is a code indicating which NE the received data is, 1 if received by Main NE 10, 2 if received by Trib NE 20 and transferred. Set. The line number indicates the line number of the OSI network 32 in the Main NE 10 or Trib NE 20 that has received the management control information. The data size indicates the data size of the received management control information.

  These pieces of information are added to the HELLO PDU data and stored and managed by the adjacency database 14a. Note that the storage units shown in the figure are stored and managed for the number of lines of the OSI network 32 to which the Main NE 10 and the Trib NE 20 are connected.

  FIG. 6 is a diagram showing the configuration of the LSP database 14b. The LSP database 14b is a database that stores LSP data. The reserved, NE code, line number, and data size are added to the LSP data and stored.

  The contents of reserved, NE code, line number, and data size are the same as in FIG. These pieces of information are added to the LSP data and stored and managed by the LSP database 14b.

  However, since there are LSP for L1 routing and LSP for L2 routing, the storage units shown in the figure include an LSP database corresponding to LSP data for L1 routing and an LSP database corresponding to LSP data for L2 routing. It will be. The LSP routing LSP database stores and manages the maximum number of L1 nodes allowed in one area, and the L2 routing LSP database allows the storage unit shown in the figure to be allowed in one area. Stored and managed for the maximum number of L2 nodes to be stored.

  FIG. 7 is a diagram showing the configuration of the forwarding database 14c. The Forwarding database 14c is a database for storing information for routing control data (destination route information), and is calculated and generated inside the apparatus based on the LSP database 14b.

Destination route information includes System ID, Lisa Budo, NE code, a line number. The System ID is an identifier included in the NSAP address and is used for searching the Forwarding database 14c. Reserved is fixed to 0, and the NE code is a code indicating which NE is to be transmitted. Set to 1 if the NE is transmitted from the Main NE 10 and 2 if it is transmitted from the Trib NE 20. The line number indicates a line number indicating which line of the connected OSI network 32 is used for transmission. The Forwarding database 14c also has an L1 routing type and an L2 routing type.

Here, the format configuration of the NSAP address will be described. The NSAP address is divided into three parts: an area address, a system ID, and an NSAP-Selector. The area address (variable length) is an address indicating an area, and the System ID (6 bytes) is an identifier that defines ES / IS in the area. NSAP-Selector (1 byte) is a field that defines a specific network service .

Next routing by communication system 1 (L1 routing) processing details will be explained. The L1 routing is performed with reference to the L1 forwarding database 14c. The Trib NE 20 once transfers the data received from the OSI network 32 to the Main NE 10 via the internal network 33 by the communication unit 24 in the Trib NE 20, and the routing processing unit 15 in the Main NE 10 receives the data.

  The Main NE 10 and the Trib NE 20 form an IP network on the internal network 33 by the internal network termination units 11 and 21 and are identified by IP addresses unique to the Main NE 10 and the Trib NE 20. In addition, the routing processing unit 15 and the communication unit 24 are assigned different UDP (User Datagram Protocol) port numbers, and designate the ports to communicate with each other.

  The routing processing unit 15 and the communication unit 24 perform data transfer by UDP / IP communication via the IP network. The Trib NE 20 transmits the received routing data such as the HELLO packet and LSP to the Main NE 10 as well as the control data (the data format used for this data transfer is shown in FIG. 4).

  Further, data received from the OSI network 32 by the Main NE 10 (that is, data received by the OSI termination unit 13) is also transferred to the routing processing unit 15 in the same manner. The routing processing unit 15 passes routing data such as HELLO packets and LSPs to the database management unit 14, and the database management unit 14 generates and manages the adjacency database 14a and the LSP database 14b from these routing information, and further these databases. A forwarding database 14c is generated and managed. When the change contents are detected from the received routing data, the corresponding database is reconstructed with respect to the adjacency database 14a, the LSP database 14b, and the forwarding database 14c.

  8 and 9 are flowcharts showing the operation of the routing processing unit 15 of the Main NE 10. Step S8 and subsequent steps show L1 routing processing in the routing processing unit 15.

  [S1] The management control information data is received directly through the OSI network 32. Alternatively, the management control information data transmitted from the Trib NE 20 through the internal network 33 is received.

  [S2] It is determined whether the received data is routing data such as a HELLO packet or LSP. If it is routing data, it will go to step S3, and if it is control data, it will go to step S4.

[S3] The routing data is transmitted to the database management unit 14, and the database management unit 14 performs database construction processing.
[S4] It is determined whether or not the area address included in the destination NSAP address of the reception control data matches the area address where the self Main NE 10 is located. If they match, go to step S6, and if not, go to step S5.

[S5] L2 routing processing is performed.
[S6] It is determined whether or not the System ID included in the destination NSAP address of the reception control data matches the System ID of the own Main NE 10. If they match, go to Step S7, and if they do not match, go to Step S8.

[S7] Since the reception control data is a network management command addressed to the own Main NE 10, it is transmitted to the data processing unit 16, and the data processing unit 16 performs the corresponding process of the command.
[S8] The reception control data is control data targeted for L1 routing. Therefore, an item having the same System ID as the System ID of the destination NSAP address of the reception control data is searched from the Forwarding database 14c. If the same System ID as that described in the NSAP address of the reception control data is in the Forwarding database 14c, the process goes to Step S10, and if not, the process goes to Step S9.

[S9] Discarded as routing destination unknown data.
[S10] Look at the NE code in the item having the same System ID, and determine whether it represents the Main NE code. If it represents the Main NE code, go to Step S12, and if it represents the Trib NE code, go to Step S11.

[S11] Control data is transmitted to the communication unit 24 of the Trib NE 20 through the internal network 33.
[S12] Look at the line number in the same item, and send control data from the OSI network 32 having this line number.

  FIG. 10 is a diagram showing a format of control data transferred from the Main NE 10 to the Trib NE 20. The format of the control data transferred to the Trib NE 20 in step S11 is shown.

  When the routing processing unit 15 of the Main NE 10 recognizes that the reception control data is not data to be output from the OSI network 32 connected to its own Main NE, it generates the transfer data 3a with the line number and the data size. Transfer to Trib NE20.

  Here, the processing after step S8 will be described using specific values. It is assumed that NE code = 1 (1 for Main NE, 2 for Trib NE) and line number # 01 are written in the item of System ID = 1 as stored information in the Forwarding database 14c. Assume that System ID = 1 is written in the destination NSAP address of the received control data.

  In this case, when the information of System ID = 1 is searched in the forwarding database 14c from step S8, the information of System ID = 1 exists in the database. This means that there is an NE to route control data in the same area.

  When the NE code is viewed from step S10, since the Main NE code 1 is described, it is known that the control data to be routed by the Main NE 10 and the line number is # 01. It is output from the OSI network 32 of the line number # 01 to be connected.

  On the other hand, a case is considered where Trib NE code 2 is written in the NE code of the item of System ID = 1. Assume that NE code = 2 and line number # 01 are written in the item of System ID = 1 as stored information in the Forwarding database 14c. In this case, in addition to the data size, the line number # 01 in the item of System ID = 1 is attached to the reception control data and transferred to the Trib NE 20 via the internal network 33. By such processing, the Main NE 10 and the Trib NE 20 can operate as one NE on the OSI network 32 while having the same NSAP address.

  Next, an embodiment will be described in which if there is control data to be transmitted from the Trib NE 20, routing processing is immediately performed on the Trib NE 20 side without being transferred to the Main NE 10 side. FIG. 11 is a diagram showing the configuration of the Main NE. The Main NE 10-1 further includes a destination route information transfer unit 17 with respect to the configuration described above with reference to FIG. Other configurations are the same.

  The destination route information transfer unit 17 transfers the destination route information stored in the current forwarding database 14c to the Trib NE 20 through the internal network termination unit 11 and the internal network 33.

  FIG. 12 is a diagram showing the configuration of the Trib NE. The communication unit 24-1 of the Trib NE 20-1 includes a destination route information storage unit 24a and a routing processing unit (sub-transmission side routing processing unit) 24b. Other configurations are the same as those in FIG.

  The destination route information storage unit 24a copies and stores the destination route information transmitted from the Main NE 10-1. When it is determined that the routing processing unit 24b receives the control data through the OSI network 32 connected to the Trib NE 20-1 itself and performs the routing process, the routing processing unit 24b searches the destination from the copied destination route information, and searches for the same destination (same System ID). When the Trib NE code is written in the item, the control data is transmitted from the corresponding line number of its own device. When the Main NE code is written, the control data is sent to the Main NE 10 via the internal network 33. Send.

  In this embodiment, the same applies until the Forwarding database 14c is created in the Main NE 10. After the Forwarding database 14c is created, the entire table information in the database is transferred to the destination route information storage unit 24a of the Trib NE 20-1 so that it can be saved and used.

  When management control information is received from the OSI network 32 of the Trib NE 20-1, if the data is routing data, it is transferred to the routing processing unit 15 of the Main NE 10-1. The data configuration at that time is as shown in FIG. 4, and the subsequent routing data processing of the routing processing unit 15 is the same as the flow of FIG.

  On the other hand, if the management control information is control data, the flow shown in FIG. 9 is executed by the routing processing unit 24b of the Trib NE 20-1, and if the data is to be transmitted from the line of the Trib NE 20-1, the specified line is used. Otherwise, the data is transferred to the Main NE 10-1.

  As described above, the contents (destination route information) of the Forwarding database 14c generated in the Main NE 10-1 are copied to the Trib NE 20-1, and the routing process can be executed in the Trib NE 20-1. Thereby, the closed routing process can be performed on the Trib NE 20-1 side, the processing load of the Main NE 10-1 is reduced, and the efficiency of information exchange between the Main NE 10-1 and the Trib NE 20-1 in the internal network 33 is also achieved. It becomes possible to plan.

As described above, by constructing the virtual NE by coordinating multiple NE, it can be operated as one complete network nodes on OSI network. This makes it possible to increase the SONET network capacity without consuming additional NSAP addresses. In addition, the line capacity can be added at a lower cost than when the existing NE is replaced with a large-capacity NE.

As a result, since a large number of network nodes can be managed in the same area without dividing the area, network node management can be simplified.
In the above description, the specific address is the NSAP address. However, the present invention is not limited to the NSAP address, and the present invention is similarly applied to other addresses as long as the purpose is to suppress address consumption as a resource at the time of capacity expansion. It is possible to apply.

(Supplementary note 1) In a communication system that performs communication by performing routing processing on a network,
It is connected to the user network through which user traffic flows and the management network through which management control information including routing data and control data flows, and is uniquely identified by a specific address on the management network, and independent of the user network and management network when capacity is increased A main transmission device that communicates by generating a virtual node having one specific address by connecting to the added device via the internal network,
At the time of capacity expansion, a sub-transmission device that communicates by sharing the same specific address as the main transmission device on a management network, generating the virtual node by connecting to the main transmission device via an internal network,
A communication system comprising:

(Additional remark 2) The said subtransmission apparatus further has a communication part which transmits all the received management control information to the said main transmission apparatus, The communication system of Additional remark 1 characterized by the above-mentioned.
(Supplementary note 3) The main transmission device generates a database that includes destination route information collected from routing data and manages it, and the control data from the sub-transmission device by itself or via an internal network. If it is received and routing processing is determined, the destination is searched from the transfer database, and if the main transmission device code is written in the item corresponding to the searched destination, the control data is calculated from the corresponding line number of the own device. And a main transmission side routing processing unit for transmitting control data to the sub-transmission apparatus via an internal network when the sub-transmission apparatus code is described. The communication system described.

  (Supplementary Note 4) The communication system according to Supplementary Note 1, wherein the main transmission device further includes a destination route information transfer unit that transfers destination route information in a transfer database to the sub-transmission device via an internal network. .

  (Supplementary Note 5) If the sub-transmission apparatus determines that the destination route information storage unit for storing the destination route information and the control data are received and performs the routing process, the sub-transmission device searches the destination from the destination route information, and searches for the destination. If the sub-transmission device code is described in the item corresponding to, control data is transmitted from the corresponding line number of the own device. If the main transmission device code is described, the main transmission device code is transmitted via the internal network. The communication system according to supplementary note 4, comprising: a sub-transmission-side routing processing unit that transmits control data to the transmission device.

(Supplementary Note 6) Main transmission that connects to a user network in which user traffic flows and a management network in which management control information including routing data and control data flows, and is uniquely identified on the management network by a specific address and performs routing processing In the device
When the capacity is increased, an internal network termination unit that performs a connection interface with the added sub-transmission device via an internal network independent of the user network and the management network;
A database management unit that generates and manages a transfer database including destination route information collected from routing data;
When it is judged that the control data is received from the sub-transmission apparatus in its own apparatus or via the internal network and the routing process is performed, the destination is searched from the transfer database, and the main transmission apparatus code is included in the item corresponding to the searched destination. Is transmitted from the corresponding line number of its own device, and when the sub-transmission device code is described, the main transmission for transmitting control data to the sub-transmission device via the internal network Side routing processor,
A main transmission apparatus comprising:

(Additional remark 7) The main transmission apparatus of Additional remark 6 characterized by further having a destination route information transfer part which transfers destination route information to the said subtransmission apparatus via an internal network.
(Supplementary Note 8) For a main transmission apparatus that is connected to a user network through which user traffic flows and a management network through which management control information including routing data and control data flows and that is uniquely identified by a specific address on the management network, In the sub-transmission device that is installed when the capacity is increased,
At the time of capacity expansion, an internal network termination unit that performs a connection interface with an existing main transmission device via an internal network independent of the user network and the management network;
A communication unit that performs communication by sharing the same specific address as the main transmission device on a management network;
A sub-transmission apparatus comprising:

(Additional remark 9) The said communication part transmits all the received management control information to the said main transmission apparatus, The subtransmission apparatus of Additional remark 8 characterized by the above-mentioned.
(Supplementary Note 10) When the communication unit determines that the destination route information storage unit that stores the destination route information transferred from the main transmission apparatus and receives control data and performs the routing process, If the sub-transmission device code is written in the item corresponding to the searched destination, the control data is transmitted from the corresponding line number of the own device, and the main transmission device code is written. And a sub-transmission-side routing processing unit that transmits control data to the main transmission device via an internal network.

(Supplementary Note 11) In a routing method in which the line capacity of a transmission device provided on a network is increased without consuming a specific address, and routing processing is performed.
A main transmission device that is connected to a user network in which user traffic flows and a management network in which management control information including routing data and control data flows, and is uniquely identified by a specific address on the management network, and an additional sub-transmission device And against
When the capacity is increased, the main transmission device is connected to the sub-transmission device that communicates by sharing the same specific address as the main transmission device on the management network via an internal network independent of the user network and the management network. And create a virtual node with one specific address,
A routing method for executing control data routing processing in the main transmission apparatus or the sub-transmission apparatus.

  (Supplementary Note 12) The sub-transmission apparatus transmits all received management control information to the main transmission apparatus, and the main transmission apparatus generates and manages a transfer database including destination route information collected from routing data, When it is judged that the control data is received from the sub-transmission apparatus in its own apparatus or via the internal network and the routing process is performed, the destination is searched from the transfer database, and the main transmission apparatus code is included in the item corresponding to the searched destination. Is transmitted from the corresponding line number of its own device, and when the sub-transmission device code is described, control data is transmitted to the sub-transmission device via the internal network. 12. The routing method according to appendix 11, which is a feature.

  (Additional remark 13) The said main transmission apparatus transfers the destination route information in a transfer database to the said subtransmission apparatus via an internal network, The said subtransmission apparatus stores destination route information, and receives control data If it is determined that routing processing is to be performed, the destination is searched from the destination route information, and if the sub-transmission device code is described in the item corresponding to the searched destination, the control data is obtained from the corresponding line number of the own device. 12. The routing method according to appendix 11, wherein control data is transmitted to the main transmission apparatus via an internal network when the transmission is performed and the main transmission apparatus code is described.

It is a principle diagram of a communication system. It is a figure which shows schematic structure of Main NE. It is a figure which shows schematic structure of Trib NE. It is a figure which shows the format of transfer information. It is a figure which shows the structure of an Adjacency database. It is a figure which shows the structure of a LSP database. It is a figure which shows the structure of a Forwarding database. It is a flowchart which shows operation | movement of the routing process part of Main NE. It is a flowchart which shows operation | movement of the routing process part of Main NE. It is a figure which shows the format of the control data transferred from Main NE to Trib NE. It is a figure which shows the structure of Main NE. It is a figure which shows the structure of Trib NE. It is a figure which shows a domain and an area. It is a figure which shows the example of the capacity expansion of the conventional SONET network. It is a figure which shows the example of the capacity expansion of the conventional SONET network.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Communication system 10, 10a, 10b Main transmission apparatus 20, 20a, 20b Subtransmission apparatus 31 User network (SONET network)
32 Management network (OSI network)
33, 33a, 33b Internal network 40, 40a, 40b Virtual node

Claims (3)

In a communication system that performs routing processing on a network and performs communication,
Connected to a user network through which user traffic flows and a management network through which management control information including routing data and control data flows, are uniquely identified by a specific address on the management network, and each of the user network and the management network A first transmission device that communicates by generating a virtual node having one specific address by connecting to another device via an independent internal network;
A second transmission that connects to the first transmission device via the internal network, generates the virtual node, and communicates on the management network while sharing the same specific address as the first transmission device Equipment,
With
The second transmission device includes:
If the received management control information is the routing data, the routing data is transferred to the first transmission device through the internal network,
If the received management control information is the control data, it is determined whether or not the control data is target data for routing processing in its own device. If the control data is the target data, routing processing is performed. And transfer from the management network connected to the device without going through the first transmission device, and transfer to the first transmission device through the internal network if it is not the target data.
A communication system characterized by the above. A user network termination unit that provides a connection interface with a user network through which user traffic flows;
A management network termination unit that performs a connection interface with a management network through which management control information including routing data and control data flows;
An internal network termination unit that performs a connection interface with an internal network independent of each of the user network and the management network;
At the time of routing processing of the control data, it is determined whether or not the control data is data subject to routing processing of its own device. If the control data is the target data, routing processing is performed and transferred from the management network And a routing processing unit for transferring to other devices through the internal network if the target data is not the target data,
It is uniquely identified by a specific address on the management network, is connected to the other device via the internal network, generates a virtual node having one specific address, and performs communication.
A transmission apparatus characterized by that. A user network termination unit that provides a connection interface with a user network through which user traffic flows;
A management network termination unit that performs a connection interface with a management network through which management control information including routing data and control data flows;
An internal network termination unit that performs a connection interface with an internal network independent of each of the user network and the management network;
A communication unit that generates a virtual node by connecting to another device via the internal network, and performs communication by sharing the same specific address as the other device on the management network;
With
The communication unit is
If the received management control information is the routing data, the routing data is transferred to the other device through the internal network,
When the received management control information is the control data, it is determined whether or not the control data is data subject to routing processing, and if the control data is the target data, routing processing is performed, Transfer from the management network without passing through another device, and transfer to the other device through the internal network if it is not the target data.
A transmission apparatus characterized by that.

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