JP3075271B2 - Call path calculation system, call path calculation method therefor, and recording medium storing control program therefor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a call path calculation system, a call path calculation method therefor, and a recording medium on which a control program is recorded.
PNNI (Private Ne) in a nous Transfer Mode (asynchronous transfer mode) exchange
The present invention relates to a multi-point call path calculation system.

[0002]

2. Description of the Related Art Hitherto, as this type of call path calculation system, there is a system for hierarchical multicast routing in an ATM network disclosed in Japanese Patent Laid-Open No. 10-32594.

In this system, a central node of a multipoint call is determined for each layer, and a multipoint call is established by calculating the shortest path to the central node for each layer.

That is, the system extends the PNNI protocol to support hierarchical multicast routing and its signaling in ATM networks, and uses extensions to core-based tree-structured algorithms. Things.

In that case, instead of a single central node,
Since multiple central nodes are maintained at each peer group and at each level of the hierarchy, a single central node is not overloaded.

In the above system, in a communication network including a plurality of nodes interconnected by a link, when multicasting a cell, the communication network is divided into a hierarchical structure of peer groups and all participants Form a multicast tree for the multicast group containing nodes.

Further, in this system, when forming a tree structure, a central node for each peer group of a multicast group is selected, and central node information is locally supplied to each peer group.

[0008]

In the above-described conventional system for hierarchical multicast routing, a link to the same level having a higher cost than a link to a lower layer having a lower cost is selected. If a link of the same level is preferentially selected over a link to a link, the cost increases from a physical point of view, so that an optimal multipoint tree cannot be formed. Further, since the PNNI protocol needs to be extended, there is no versatility.

Accordingly, an object of the present invention is to solve the above-mentioned problems, and to add a certain node to a multipoint call at the minimum cost when adding the node to the multipoint call. Is to provide a call path calculation system, a call path calculation method thereof, and a recording medium on which a control program thereof is recorded.

[0010]

SUMMARY OF THE INVENTION A call path calculation system according to the present invention comprises a plurality of physical nodes interconnected by links and a plurality of logical nodes interconnected by links. A call path calculation system for searching for an optimal branch node to a destination node based on configuration information indicating a configuration of a tree structure and performing a path calculation of a multipoint call, wherein the tree structure of the tree structure is calculated at the time of calculating the path of the multipoint call. includes a node retrieval means for retrieving the optimal branch node investigating the links including links between nodes across a hierarchy, the node search hand
From the link at the same hierarchical level as the own node and the own node
The link to the lower hierarchical level is considered at the same time .

A call path calculation method according to the present invention shows a tree structure of a communication network including a plurality of physical nodes interconnected by links and a plurality of logical nodes interconnected by the links. A call route calculation method for searching for an optimum branch node to a destination node based on configuration information and calculating a route of a multipoint call, wherein a node between nodes straddling the tree structure hierarchy when calculating the route of the multipoint call. investigating the link including a link comprises the step of searching the optimal branch node, the own in the step of searching the optimal branch node
A link at the same hierarchical level as the node and the lower level from the own node
The link to the layer level is taken into account at the same time .

A recording medium on which a call path calculation control program according to the present invention is recorded includes a plurality of physical nodes interconnected by a link and a plurality of logical nodes interconnected by the link. A recording medium storing a call path calculation control program for causing a computer to perform a path calculation of a multipoint call by searching for an optimum branch node to a destination node based on configuration information indicating a configuration of a tree structure, The calculation control program causes the computer to search for the optimum branch node by examining a link including a link between the nodes straddling the hierarchy of the tree structure at the time of calculating the route of the multipoint call , and automatically search for the optimum branch node. No
Link at the same hierarchy level as the node and the lower hierarchy from the own node
The link to the level is also considered at the same time .

[0013] That is, the call path calculation system of the present invention provides a system for calculating the path of a multipoint call that is optimal from the viewpoint of the entire network when calculating the path of a PNNI multipoint call in an ATM exchange. It is.

More specifically, the call path calculation system of the present invention comprises a network configuration information storage unit for storing PNNI network configuration information, and a multipoint call tree storage unit when a call setup request is received by a call setup request receiving device. Call path calculation means for finding an optimum path from the multipoint tree information stored in the network and the PNNI network configuration information stored in the network configuration information storage unit And the same level link investigating means for obtaining the same are obtained.

Therefore, in the call path calculation system of the present invention, the same level link and the link to the lower hierarchical level are considered at the same time when the call path is calculated, so that the call level calculation system can be compared with the method of considering the same level link of the logical level first. Therefore, since the most suitable branch node is selected, it is possible to obtain the optimum multipoint call route based on the PNNI network configuration information.

Further, in a general PNNI network, the aggregation at the same level link of the logical level is larger at the actual physical level to perform aggregation such as a logical node represented by a simple point. Links to hierarchical levels do not. Therefore, in the call path calculation system of the present invention, since the overall cost is reduced by using a link to a lower hierarchical level than a high-cost same-level link, the PNNI network configuration is viewed from a physical viewpoint. In such a case, it is possible to configure a multipoint call with a minimum cost.

[0017]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a PNNI multipoint call path calculation system in an ATM exchange according to an embodiment of the present invention. In the figure, a PNNI multipoint call path calculation system according to an embodiment of the present invention includes a PNNI network configuration information receiving apparatus 1 for receiving PNNI network configuration information.
And a data processing device 2 operating under program control
A call setting request receiving device 3 for receiving a call setting request;
And a storage device 4 for storing information.

The data processing device 2 is a PNNI network configuration information handling means (hereinafter referred to as configuration information handling means) 2
1; a multipoint call path calculating means (hereinafter referred to as call path calculating means) 22; and a control memory 27.

The call path calculation means 22 is a node search means (hereinafter referred to as a node search means) 23 which branches optimally to the destination.
And route creation means (hereinafter referred to as route creation means) 26 from its own node to the branch node. The node searching means 23 comprises the same level link checking means 24 and the link checking means 25 to the lower hierarchical level.

The configuration information handling means 21 registers the PNNI network configuration information received from another ATM exchange (not shown) in the network configuration information storage section 41 of the storage device 4, and the own ATM exchange (not shown). The generated PNNI network configuration information is registered in the network configuration information storage unit 41.

Node search means 23 of call path calculation means 22
Is the PNN stored in the network configuration information storage unit 41
The destination of this call is determined from the I network configuration information, and the PNNI network configuration information stored in the network configuration information storage unit 41 and the multipoint call tree storage unit 42
A search is made for a node that optimally branches to the destination from the multipoint call tree information stored in.

The same level link checking means 24 of the node searching means 23 uses the PNNI network configuration information stored in the network configuration information storage section 41 and the multipoint call tree information stored in the multipoint call tree storage section 42 to determine the PNNI. Investigate links at the same hierarchical level.

The link checking means 25 for linking to the lower hierarchical level stores the PNNI stored in the network configuration information storage 41.
From the network configuration information and the multipoint call tree information stored in the multipoint call tree storage unit 42, P
A survey is performed on the link to the lower hierarchical level of the NNI.

The route creation means 26 finds the route to the optimum branch node obtained by the node search means 23 from the multipoint call tree information stored in the multipoint call tree storage unit 42.

When the call setting request receiving device 3 receives a call setting request from another ATM exchange or terminal (not shown),
A route creation request is made to the multipoint call route calculation means 22. The storage device 4 includes a network configuration information storage unit 41,
And a multipoint call tree storage unit 42.

The network configuration information storage unit 41 stores a PNN
The PNNI network configuration information received from another ATM switch by the I network configuration information data receiving device 1 and the PNNI network configuration information generated by the own ATM switch are stored. The multipoint call tree storage unit 42 stores how the multipoint call tree at that time is set up.

FIG. 2 is a flowchart showing the processing operation of the configuration information handling means 21 of FIG. 1, and FIG. 3 is a flowchart showing the processing operation of the call path calculation means 22 of FIG.
Referring to FIGS. 1 to 3, P according to an embodiment of the present invention will be described.
The operation of the NNI multipoint call path calculation system will be described. The processing operations shown in FIGS. 2 and 3 are realized by the configuration information handling means 21 and the call path calculating means 22 executing a program stored in the control memory 27, and the control memory 27 includes a ROM (read only memory). ) Or a floppy disk can be used.

First, in one embodiment of the present invention, PNNI network configuration information is created as specified in the PNNI specification. PNNI network configuration information data receiving device 1
Receives the PNNI network configuration information from another ATM exchange (step S1 in FIG. 2), or
When the exchange generates PNNI network configuration information (step S2 in FIG. 2), the configuration information handling unit 21 sends the PNNI network configuration information to the storage device 4 and stores it in the network configuration information storage unit 41 (step S3 in FIG. 2). ).

When receiving the call setting request via the call setting request receiving device 3, the call path calculating means 22 refers to the network configuration information storage unit 41 to determine the destination node (step S11 in FIG. 3). At this time, the node search unit 23 searches the network configuration information storage unit 41 and the multipoint call tree storage unit 42 for a node that optimally branches to the destination (steps S12 to S17 in FIG. 3).

If the destination node is already on the multipoint call tree, the node search means 23 determines that the optimum branch node has been found because that node is the optimum branch node (step S12 in FIG. 3).

When the destination node is not on the multipoint call tree, the node search means 23 finds the optimum branch node by referring to the network configuration information storage unit 41. This process is based on a general route calculation algorithm such as Dijkstra's algorithm.

First, the call path calculating means 22 refers to the network configuration information storage unit 41 and selects a link with the lowest cost from links not yet investigated among links from the node of interest (step in FIG. 3). S13).

If the link selected as the link with the lowest cost among the links which have not yet been investigated is the link of the same level (step S in FIG. 3).
14) The same-level link checking means 24 checks links of the same level (step S16 in FIG. 3).

If the node at the link of the same level detected in the above investigation is already on the multipoint call tree, the node search means 23 determines that the optimum branch node has been found because that node is the optimum branch node. A determination is made (step S12 in FIG. 3).

If the link selected as the link with the lowest cost among the links that have not yet been investigated is the link to the lower hierarchical level (step S15 in FIG. 3), the link to the lower hierarchical level is determined. Investigation means 25
To check the link to the lower hierarchical level (step S17 in FIG. 3).

If the node to which the link to the lower hierarchical level detected in the above investigation is already located on the multipoint call tree, the node searching means 23 becomes the optimum branch node. It is determined that it has been found (step S12 in FIG. 3). Node search means 2
In step 3, the above processing is repeated until the optimum branch node is found (steps S12 to S17 in FIG. 3).

When it is determined that the optimum branch node has been found by the node search means 23, the route creation means 26 refers to the multipoint call tree storage section 42 and calculates a route from its own node to the branch node (FIG. 3). Step S1
8).

Finally, the call path calculation means 22 attaches the path from its own node to the branch node obtained by the path creation means 26 and the path from the branch node to the destination node obtained by the node search means 23, and attaches itself. A path from the node to the destination node is obtained, this is recorded in the multipoint call tree storage unit 42, a call setting process is performed, and the process ends (step S19 in FIG. 3).

FIG. 4 is a diagram showing an example of a typical PNNI-based network for explaining the operation of one embodiment of the present invention. In the figure, A1, A2, A3, B1,
B2, B3, C1, C2, C3 are physical nodes, A, B,
C is a logical node [peer group (PG: Peer Gr)
up)].

FIG. 5 is a diagram showing an example of the network configuration information held by each of the nodes A1, A2, A3 belonging to the peer group A of FIG. In the figure, there is an uplink from node A2 to node B and an uplink from node A3 to node C. This network configuration information is created based on the specifications of the PNNI by the procedure of steps S1 to S3 in FIG. Note that the numerical value of the link between the nodes in the figure represents the cost of the link.

FIG. 6 is a diagram showing a state in which the route from node A1 to node B and the route from node A3 to node A3 in FIG. 5 are registered. In the figure, the state after the route to the node B and the route to the node A3 are registered as multipoint information in the network configuration information of FIG. 5 viewed from the node A1. Represents a multipoint tree.

The processing operation of the PNNI multipoint call path calculation system according to one embodiment of the present invention will be specifically described with reference to FIGS. Here, it is assumed that the call setting request receiving device 3 has received a call setting request.

First, it is assumed that the call path calculation means 22 determines that the destination node of the call setting request is the logical node C by referring to the network configuration information storage unit 41 (step S11 in FIG. 3). In this case, the destination node C
Since is not on the multipoint call tree, the optimum branch node has not been found at this time (step S12 in FIG. 3).

Next, the call path calculation means 22 refers to the network configuration information storage unit 41 and selects the link with the minimum cost from the links from the node C that have not yet been investigated. Here, in the above example, the uplink between the node A3 and the node C has a smaller cost than the link between the node B and the node C, so the uplink between the node A3 and the node C is It is selected (step S13 in FIG. 3).

The call path calculation means 22 determines that the link selected as the link with the lowest cost among the links which have not been investigated is the link to the lower hierarchical level (uplink between the nodes A3 and C). (FIG. 3 step S
15) Investigate the link to the lower hierarchical level (uplink between the node A3 and the node C) by the link investigating means 25 to the lower hierarchical level (step S17 in FIG. 17).

Since the node (node A3) ahead of this link is already in the multipoint call tree, the call path calculation means 22 finds the optimum branch node because this node is the optimum branch node (FIG. 3 steps S
12).

When it is determined that the optimum branch node has been found by the node search unit 23, the route creation unit 26 refers to the multipoint call tree storage unit 42, and from the own node (node A1) to the branch node (node A3). Is calculated (step S18 in FIG. 3).

Finally, the call path calculation means 22 calculates the path from its own node to the branch node (node A 1 → node A 2 → node A 3) determined by the path creation means 26 and the branch node determined by the node search means 23. The path from the own node to the destination node (node A1 → node A2) is attached by attaching the path to the destination node (node A3 → node C).
→ node A3 → node C), and records this in the multipoint call tree storage unit 42, performs call setting processing, and ends the processing (step S19 in FIG. 3).

As described above, when calculating the call route, the same level link and the link to the lower hierarchical level are simultaneously considered by using the same level link investigating means 24 and the link investigating means 25 to the lower hierarchical level, so that As compared with a method in which links at the same logical level are considered first, an optimum branch node can be selected. Therefore, when a certain node is added to the multipoint call, the most appropriate branch node at that time can be selected, and the node can be added to the multipoint call at the minimum cost.

Further, in a general PNNI network, aggregation is performed as a logical node by a simple point, so that the cost of a link at the same logical level is higher at the actual physical level, but lower. Links to the physical hierarchy level are not. Therefore, in one embodiment of the present invention, the overall cost can be reduced by using a link to a lower hierarchical level than a link of the same level which is expensive. Therefore, in one embodiment of the present invention, a multipoint call can be configured at a minimum cost when the PNNI network configuration is viewed from a physical point of view.

4 and 6 will be described using a specific example.
In a multipoint call from node A1 at
From the physical point of view, when a call with the final destination node being node C1 is newly added, and when the link between the nodes B and C, which are the same level links, is selected from the destination node C in FIG. , Node B1 in FIG.
It follows the route of B3, C2, and C1, which is costly larger than the route from node A3 to node C1.

FIG. 7 is a block diagram showing the configuration of a PNNI multipoint call path calculation system in an ATM exchange according to another embodiment of the present invention. In the figure, a PNNI multipoint call path calculation system according to another embodiment of the present invention includes a node search means 2 in a data processing device 5.
A shortest route calculation means 51 between two points is provided in place of 3;
The configuration is the same as that of the embodiment of the present invention except that a shortest route storage unit 43 between two points is added to the storage device 6, and the same components are denoted by the same reference numerals. The operation of the same component is the same as that of the embodiment of the present invention.

The shortest route calculating means 51 between two points includes the same level link checking means 52 and the link checking means 53 to the lower hierarchical level. The control memory 54 stores a program executed by each unit in the data processing device 5, and thus has a different code from that of the control memory 27 according to the embodiment of the present invention.

The shortest path calculating means 51 between the two points obtains the shortest path between the two points from the PNNI network configuration information stored in the network configuration information storage section 41, and stores the result in the shortest path storage section 43 between the two points. sign up.

The same-level link checking means 52 checks the PNNI network configuration information stored in the network configuration information storage unit 41 for PNNI links of the same hierarchical level.

The link investigating means 53 for the lower hierarchical level stores the PNNI stored in the network configuration information storage 41.
An investigation is performed on the link from the network configuration information to the lower hierarchical level of the PNNI. The shortest path between two points storage unit 43 stores the shortest path between any two points with respect to the nodes stored in the network configuration information storage unit 41.

FIG. 8 shows the configuration information handling means 21 and 2 shown in FIG.
FIG. 9 is a flowchart showing a processing operation of the shortest route calculation means 51 between points, and FIG. 9 is a flowchart showing a processing operation of the call route calculation means 22 of FIG.

The operation of the PNNI multipoint call path calculation system according to another embodiment of the present invention will be described with reference to FIGS. The processing operations shown in FIGS. 8 and 9 are performed by the configuration information handling unit 21 and the call route calculating unit 22.
And the shortest route calculation means 51 between the two points
The control memory 54 is implemented by executing a program stored in the ROM and a ROM or a floppy disk can be used.

Since the processing operations of steps S21 to S23 in FIG. 8 are the same as the processing operations of the PNNI network configuration information data receiving device 1 and the configuration information handling means 21 shown in FIG. 1, the description of the processing operations is omitted. I do.

After storing the PNNI network configuration information in the network configuration information storage section 41, the shortest path calculation means 51 between the two points calculates the shortest path between the two points with reference to the network configuration information storage section 41, and It is stored in the shortest route storage section 43 between points (step S2 in FIG. 8).
4).

In this calculation, the optimum branch node is obtained with reference to the network configuration information storage unit 41. This process is based on a general route calculation algorithm such as Dijkstra's algorithm. At this time, the same level link checking means 52 and the link checking means 53 to the lower hierarchical level are used.
In the above, the link of the same level and the link to the lower hierarchical level are investigated.

When receiving the call setting request via the call setting request receiving device 3, the call path calculating means 22 refers to the network configuration information storage unit 41 to determine the destination node (step S31 in FIG. 9).

The call path calculation means 22 refers to the network configuration information storage section 41 and the shortest path storage section 43 between two points, and determines that the cost between any node on the multipoint call tree and the destination node is the minimum. Search for nodes on the multipoint call tree. The node selected here becomes the optimal branch node (step S32 in FIG. 9).

When the optimum branch node is searched, the route creation means 26 refers to the multipoint call tree storage unit 42 and calculates a route from its own node to the branch node (step S33 in FIG. 9).

Finally, the call path calculating means 22 calculates the path from its own node to the branch node obtained by the path creating means 26 and the path from the branch node to the destination node obtained by the shortest path calculating means 51 between two points. Then, the route from the own node to the destination node is obtained, this is recorded in the multipoint call tree storage unit 42, and the process is terminated (step S34 in FIG. 9).

FIG. 10 is a diagram showing the contents stored in the shortest route storage unit 43 between the two points in FIG. FIG. 10A shows a route and cost from the nodes A1 and A3 to the destination node A2 in FIG. 5, and FIG. 10B shows a route and cost from the nodes A1 and A2 to the destination node A3 in FIG. FIG. 10
(C) shows the route and cost from the nodes A1, A2, A3, C to the destination node B in FIG. 5, and FIG. 10 (d) shows the route from the nodes A1, A2, A3, B to the destination node C in FIG. Are shown along with the route and cost.

Referring to FIGS. 4 to 6 and FIGS. 7 to 10, a specific example of the processing operation of the PNNI multipoint call path calculation system according to an embodiment of the present invention will be described. The network configuration shown in FIGS. 4 to 6 is the same as that of the embodiment of the present invention.

First, in the data processing device 5, as shown in FIG. 10, a shortest route between two points is calculated by the shortest route calculating means 51 between the two points, and this is stored in the shortest route storage unit 43 between the two points. (Step S2 in FIG. 8)
4).

The first field corresponding to the destination nodes A2, A3, B, and C in FIG. 10 is the route from each node to the destination nodes A2, A3, B, and C, and the second field is the cost of the route. Each is represented. It is not necessary to store the route from a node at a higher level than the destination nodes A2, A3, B and C to the destination nodes A2, A3, B and C due to the nature of the PNNI.

The route from the node A, which is a direct parent of the node A1, to each destination node is finally the node A1.
Since node A2 and node A3 descend to node B and node C, node A is not considered.

Assume that the call setting request receiving device 30 has received a call setting request. First, the call path calculation means 22
It is assumed that has determined that the destination node of this call setting request is the logical node C by referring to the network configuration information storage unit 41 (step S31 in FIG. 9).

The call path calculation means 22 includes a network configuration information storage section 41 and multipoint call tree storage sections 42 and 2
By referring to the shortest path storage unit 43 between points, a node on the multipoint call tree where the cost between any node on the multipoint call tree and the destination node is minimized is searched.

In this case, the call route calculating means 22
3 is selected and determined to be the optimal branch node (step S32 in FIG. 9). The call route calculation means 22 is a route creation means 2
6, the route from the own node (node A1) to the branch node (node A3) is calculated with reference to the multipoint call tree storage unit 42 (step S3 in FIG. 9).
3).

Finally, the call route calculating means 22 calculates the route from its own node to the branch node (node A 1 → node A 2 → node A 3) obtained by the route creating means 26 and the shortest route calculating means 51 between the two points. The obtained path from the branch node to the destination node (node A3 → node C) is attached to the path from the own node to the destination node (node A).
1 → node A2 → node A3 → node C), and this is recorded in the multipoint call tree storage unit 42, and the processing is terminated (step S34 in FIG. 9).

In another embodiment of the present invention, the shortest route between two points is stored in advance as cache data, so that in addition to the effects of the above-described embodiment of the present invention, the route calculation after receiving a call setting request is performed. A new effect is obtained in that the processing time of the call setting request can be reduced as compared with performing the algorithm.

[0076]

As described above, according to the present invention, a tree structure of a communication network including a plurality of physical nodes interconnected by links and a plurality of logical nodes interconnected by links is provided. When searching for the optimal branch node to the destination node based on the configuration information indicating the configuration and calculating the route of the multipoint call, the link including the link between the nodes spanning the hierarchy of the tree structure is investigated to determine the optimal branch node. By searching for, there is an effect that when a certain node is added to the multipoint call, the node can be added to the multipoint call with the minimum cost, and the multipoint call can be configured with the minimum cost.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a PNNI multipoint call path calculation system in an ATM exchange according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a processing operation of a PNNI network configuration information handling means of FIG. 1;

FIG. 3 is a flowchart showing a processing operation of a multipoint call route calculating means of FIG. 1;

FIG. 4 is a diagram showing an example of a typical PNNI-based network for explaining the operation of one embodiment of the present invention.

FIG. 5 is a diagram illustrating an example of network configuration information held by a peer group A in FIG. 4;

FIG. 6 is a diagram showing a state in which a path from a node A1 to a node B and a path from a node A3 in FIG. 5 are registered.

FIG. 7 is a block diagram showing a configuration of a PNNI multipoint call path calculation system in an ATM exchange according to another embodiment of the present invention.

8 is a flowchart showing processing operations of a PNNI network configuration information handling unit and a shortest route calculation unit between two points in FIG. 7;

FIG. 9 is a flowchart showing a processing operation of a multipoint call route calculating means of FIG. 7;

10A is a diagram showing a route and costs from nodes A1 and A3 to a destination node A2 in FIG. 5, and FIG.
5A shows a path from the nodes A1, A2 to the destination node A3 and the cost, and FIG. 5C shows the nodes A1, A2, A in FIG.
5 is a diagram showing a route and cost from C and C to the destination node B, and FIG. 5D is a diagram showing a route and cost from nodes A1, A2, A3 and B to the destination node C in FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 PNNI network configuration information receiving device 2, 5 data processing device 3 call setting request receiving device 4, 6 storage device 21 PNNI network configuration information handling device 22 multipoint call route calculation device 23 node search device for optimal branch to destination 24, 52 Same level link investigating means 25, 53 Link investigating means to lower hierarchical level 26 Route creating means from own node to branch node 27, 54 Control memory 41 Network configuration information storage unit 42 Multipoint call tree storage unit 43 Between two points Shortest route storage unit 51 Shortest route calculation means between two points

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-10-32594 (JP, A) JP-A-10-164074 (JP, A) JP-A-10-243029 (JP, A) JP-A-11-104 205331 (JP, A) IEICE Technical Report IN97-150 IEICE Technical Report IN97-181 NEC Technical Report, Vol. 68-72 (58) Field surveyed (Int. Cl. ⁷ , DB name) H04L 12/28

Claims (12)

(57) [Claims] 1. A destination node based on configuration information indicating the configuration of a tree structure of a communication network including a plurality of physical nodes interconnected by a link and a plurality of logical nodes interconnected by the link. A call route calculation system that searches for an optimal branch node to calculate a route of a multipoint call, and investigates a link including a link between nodes across the hierarchy of the tree structure when calculating the route of the multipoint call. have a node retrieval means for retrieving the optimal branch node Te, the node search
Whether the means is a link at the same hierarchical level as the own node and the own node
And links to lower hierarchy levels at the same time.
Call path computation system characterized by the. 2. The same-level link in which the minimum-cost node searches for a link at the same hierarchical level as its own node when searching for a minimum-cost node by not searching for the optimal branch node. Investigating means, and link investigating means to a lower hierarchical level for performing an investigation on a link from its own node to a lower hierarchical level when the node with the least cost is searched for a node with the least cost due to unsearching of the optimal branch node. The call route calculation system according to claim 1, further comprising: 3. A shortest path calculating means for obtaining a shortest path between two points from the configuration information, and a shortest path storing means for storing a calculation result of the shortest path calculating means between the two points. And calculating the route of the multipoint call by searching for the optimal branch node to the destination node based on the configuration information and the calculation result of the shortest route calculation means between the two points. The call path calculation system according to claim 1. 4. The shortest path calculating means between the two points, the search for the lowest cost node at the same hierarchical level as the own node when searching for the lowest cost node due to the unsearched optimum branch node is performed. The same level link investigating means for performing a search for a link from the own node to a lower hierarchical level when the node having the minimum cost is searched for a node having the minimum cost due to the unsearched for the optimal branch node. 4. The call route calculation system according to claim 3, further comprising: link investigation means. 5. A destination node based on configuration information indicating a tree structure of a communication network including a plurality of physical nodes interconnected by a link and comprising a plurality of logical nodes interconnected by the link. A route calculation method for calculating a multipoint call path by searching for an optimal branch node to the multi-point call, and examining a link including a link between nodes across the tree structure hierarchy when calculating the multipoint call path. It has a step of retrieving the optimal branch node Te, searching the optimal branch node
Link at the same hierarchical level as the own node
Link and link from own node to lower hierarchy level
A call route calculation method characterized by taking into account . 6. The method according to claim 1, wherein the step of retrieving the optimal branch node includes the step of retrieving the least-cost node at the same hierarchical level as the own node when retrieving the least-cost node due to the unretrieved optimal branch node. Performing the search, and performing a search on the link from the own node to the lower hierarchical level when the node with the minimum cost is searched for the node with the minimum cost due to the unsearched optimal branch node. The method according to claim 5. 7. A method for obtaining a shortest path between two points from the configuration information, searching for an optimum branch node to a destination node based on the configuration information and the shortest path between the two points, and searching for a multipoint call. 6. The call route calculation method according to claim 5, wherein the route calculation is performed. 8. The step of obtaining the shortest route between the two points includes the step of searching for a node having the lowest cost due to a non-search of the optimum branch node, wherein the node having the lowest cost targets a link at the same hierarchical level as its own node. Performing a search, and performing a search on the link from the own node to a lower hierarchical level when the node with the minimum cost is searched for a node with the minimum cost due to the unsearched for the optimal branch node. The call path calculation method according to claim 7, wherein 9. A destination node based on configuration information indicating a tree structure of a communication network including a plurality of physical nodes interconnected by links and a plurality of logical nodes interconnected by the links. A call path calculation control program for causing a computer to perform a path calculation of a multipoint call by searching for an optimum branch node to the computer, wherein the call path calculation control program instructs the computer to execute the multipoint call At the time of route calculation, a link including a link between nodes spanning the hierarchy of the tree structure is investigated to search for the optimal branch node.
From the link at the same hierarchical level and the current node to the lower hierarchical level
A recording medium storing a call path calculation control program characterized by simultaneously considering a link to a call path. 10. The call path calculation control program causes the computer to search for the optimal branch node. When the computer searches for the optimal branch node, the computer searches the optimal branch node for the node with the minimum cost. A search is performed for links at the same hierarchical level, and when searching for a node with the lowest cost due to the unsearched search for the optimal branch node, the search for the link from the own node to the link at the lower hierarchical level is performed. A recording medium on which the call path calculation control program according to claim 9 is recorded. 11. The call path calculation control program causes the computer to determine a shortest path between two points from the configuration information, and optimally branches to a destination node based on the configuration information and the shortest path between the two points. 10. The recording medium according to claim 9, wherein a node is searched to calculate a route of a multipoint call. 12. The call path calculation control program, when causing the computer to obtain a shortest path between the two points, when the least cost node is searched for when the optimum branch node has not been searched yet, A search is performed for links at the same hierarchical level as the own node, and when searching for the lowest cost node due to the unsearched optimal branch node, the node with the lowest cost targets the link from the own node to the lower hierarchical level. 12. A recording medium storing a call path calculation control program according to claim 11, wherein the investigation is performed.