JP2005151027A - Optimum routing setting method, apparatus, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optimum routing setting method, apparatus, and program for dynamically realizing routing setting by exchanging abstract information between service provider networks, without exchanging concrete topology information among them. <P>SOLUTION: Routers 11 to 19 within own SP 10 calculate optimum routings with respect to all ASBRs 17 to 19. Routers 21 to 29 in an external SP 20 calculate optimum routings from all ASBRs 27 to 29. The ASBRs 17 to 19 and ASBRs 31 to 33 in an IX 30 exchange aggregated path information, the ASBRs 31 to 33 and the ASBRs 27 to 29 exchange aggregated path information, and the ASBRs 31 to 33 mutually exchange aggregated path information with each other. Further, the optimum routing setting method decides an optimum border router within own SP 10 and an optimum border router in the external SP 20. Then abstract information of routers, at a start end point and an end point and the optimum border routers, is advertised among the border routers. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  In the present invention, in the traffic engineering (Traffic Engineering) for route setting using MPLS (Multiprotocol Label Switching), service provider networks that are closed networks in terms of policies exchange closed network information abstracted from each other. The present invention relates to a method and apparatus for setting an optimized MPLS path end-to-end.

  Conventionally, when connecting between service provider networks, the service provider network (hereinafter referred to as “own network”) is connected to an external service provider network (hereinafter referred to as “external network”) by BGP (Border Gateway). Protocol information was advertised by using Protocol or by an aggregated Prefix by static route setting. The border router used at that time is determined by the manager of the own network using BGP IP preference or MED, and is not determined by involving the optimized path of the external network. It was. The border router may be determined by the static setting, but the optimum border router has not been dynamically determined. In such a route setting, traffic always passes through the same connection link from its own network to the external network. On the other hand, advertising specific topology information of the own network to the external network is not desirable from the viewpoint of policies such as security regulations of the own network.

  FIG. 1 is a schematic configuration diagram for explaining that traffic passes through the same connection link when a service provider network is advertised by BGP. In the figure, the service provided with a label edge router (hereinafter referred to as “LER”) 3, an autonomous system boundary router (hereinafter referred to as “ASBR”) 5, and an ASBR 6 as starting points. The network includes a provider network 1 (hereinafter referred to as “SP1”) and an external service provider network 2 (hereinafter referred to as “SP2”) including LER4, ASBR7, and ASBR8 which are termination points. SP1 and SP2 are connected by ASBR5 and ASBR7, ASBR6 and ASBR8, respectively. Under such a configuration, when route information is advertised from SP2 to SP1 using BGP, the route from LER3, which is the start point in SP1, to LER4, which is the end point in SP2, is shown in FIG. As described above, if LER3, ASBR5, ASBR7, and LER4 are set, traffic will pass through this connection link. Since this connection link is not a link based on a path dynamically taking traffic engineering into account, new signaling passes through the same connection link. There are various techniques for setting such a route (see Non-Patent Documents 1 and 2).

“GR2000 Software Manual”, [online], Hitachi, Ltd., [searched on November 5, 2003], Internet <URL: http://www.hitachi.co.jp/Prod/comp/network/ gr2000 / manual / html_a / kaisetsu / 0196.htm> “Learn about MPLS technology and its latest trends”, [online], Atmark IT Co., Ltd. [searched on November 5, 2003], Internet <URL: http://www.atmarkit.co.jp/fnetwork/ tokusyuu / 11mpls / mpls01.html>

  As described above, in the conventional technology, a path taking into account dynamic traffic engineering is not set in setting a route between service provider networks, and traffic always passes through the same connection link. For this reason, the route is shifted to a specific connection link, resulting in inconveniences such as inefficient use of bandwidth. In this case, it is desirable to set a path that dynamically considers traffic engineering. Specifically, as shown in FIG. 2, in the configuration equivalent to FIG. 1, the new signaling does not pass through the fixed connection links of LER1, ASBR3, ASBR5, and LER8, but is different from LER1, ASBR4. , It is desirable to set to pass through the connection link of ASBR6 and LER8.

  Therefore, the present invention has been made in view of such a problem, and the object thereof is to dynamically optimize by exchanging abstract information without exchanging specific topology information between service provider networks. It is an object to provide an optimum route setting method, apparatus, and program for realizing route setting close to a generalized route.

  In order to solve the above-mentioned problem, the invention of claim 1 is characterized in that the first network and the second network that conceal a specific topology include a first border router and a second network adjacent to each network. MPLS traffic engineering path between the border routers when setting the optimum route from the start point router in the first network to the end point router in the second network under the configuration connected by the border router And calculating the optimum route from the start router to the first border router, calculating the optimum route from the second border router to the end router, and the first and second border routers. And exchanges aggregate route information representing network prefixes with the two border routers, and based on the information of the optimum route and the aggregate route, the optimum border router in the first network and the optimum route in the second network are exchanged. Determine the border router, the first Between the field router and a second border router, and wherein the exchange of abstraction information consisting of start point router, information of the end point router and optimal border router.

  The invention according to claim 2 is a configuration in which a first network and a second network that conceal a specific topology are connected by a first border router and a second border router adjacent to each network. The method for setting an MPLS traffic engineering path between the border routers when setting the optimum route from the start point router in the first network to the end point router in the second network. Calculating an optimum route from the start point router to the first border router, exchanging aggregate route information representing a network prefix between the first border router and the second border router, and An optimum border router in the first network is determined based on the aggregated route information, and a start point router, a end point router, the optimum border router, and a end point between the first border router and the second border router Reachability to the point router And wherein the exchange of abstraction information consisting of information of the optimal border routers in the authorization capability of the second network.

  The invention according to claim 3 is a configuration in which a network that conceals a specific topology is connected by a border router adjacent to another network, from a router that is a starting point to a terminal point of another network. In the router device provided as a border router for setting the MPLS traffic engineering path when setting the optimum route to the router, the means for calculating the optimum route from the router as the starting point to its own border router, The network Prefix is expressed between the means for calculating the optimum route from the border router to the end point router, the means for holding the topology tree information of each optimum route, and the border router of the other network. Means for exchanging aggregate route information, and a method for determining an optimum border router that constitutes an optimum route based on the topology tree information and the aggregate route information. When, among other border routers, characterized in that a means for exchanging abstracted information consisting of start point router, information of the end point router and optimal border router.

  According to the invention of claim 4, in a configuration in which networks that conceal a specific topology are connected by a border router adjacent to another network, a router serving as a starting point is connected to a terminal point of another network. A router device provided as a border router for setting an MPLS traffic engineering path when setting an optimum route to a router to be calculated, a means for calculating an optimum route from a router as a starting point to its own border router; Means for holding topology tree information of the optimum route, means for exchanging aggregate route information representing a network prefix between the border routers of other networks, and an optimum route based on the topology tree information and the aggregate route information. Between the means for determining the optimum border router constituting the network and the other border routers, the start point router, the end point router, the optimum border router, and Characterized by comprising a means for exchanging abstracted information comprising the reachability to the end point router from the optimum boundary router information of the identifiable other networks.

  According to the invention of claim 5, in a configuration in which the networks that conceal a specific topology are connected by a border router adjacent to another network, the router that is the starting point is connected to the end point of the other network. This program sets the MPLS traffic engineering path when setting the optimum route to the router to be calculated, and calculates the optimum route from the router that is the starting point to its own border router in the computer constituting the border router. Between the processing to calculate the optimal route from its own border router to the router as the termination point, the processing to retain the topology tree information of each of the optimal routes, and the boundary router of the other network, A process for exchanging aggregate route information representing a network prefix, and an optimum boundary route that constitutes an optimum route based on the topology tree information and the aggregate route information. A process of determining, among other border routers, characterized in that to execute a process of exchanging abstracted information consisting of start point router, information of the end point router and optimal border router.

  According to the invention of claim 6, in a configuration in which networks that conceal a specific topology are connected by a border router adjacent to another network, a router serving as a starting point is connected to a terminal point of another network. This program sets the MPLS traffic engineering path when setting the optimum route to the router to be calculated, and calculates the optimum route from the router that is the starting point to its own border router in the computer constituting the border router. Processing for holding topology tree information of the optimum route, processing for exchanging aggregate route information representing network prefixes with border routers of other networks, topology tree information and aggregate route information Between the process of determining the optimum border router that constitutes the optimum route based on the above and other border routers, Field router, and is characterized in that to execute a process of exchanging abstracted information consisting of the optimal border router information of identifiable another network reachability to the end point router.

  According to the present invention, only the information of the start point router, the end point router and the boundary router is exchanged between the boundary routers by the route calculated by optimization in each network, and the route between the networks is changed between the boundary routers. It was made to join. In addition, information that can confirm reachability to the router at the end point is exchanged between the border routers by the route calculated by optimization in the first network, and the routes between the networks are joined between the border routers. . As a result, in the optimum route setting from the start point to the end point router, MPLS that dynamically considers the optimal traffic engineering can be used by exchanging open abstraction information without advertising specific topology information. It is possible to set a path. Therefore, the set route does not deviate to a specific connection link, and it is possible to avoid inconveniences such as, for example, inferior bandwidth usage efficiency.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
First, a first embodiment will be described with reference to FIG. FIG. 3 is a schematic configuration diagram illustrating a case where abstraction information is exchanged between border routers. This communication system has its own service provider network 10 (hereinafter referred to as “own SP10”) including LER 11 to 13, a label switching router (hereinafter referred to as “LSR”) 14 to 16 and ASBR 17 to 19. An external service provider network 20 (hereinafter referred to as “external SP20”) including LER 21 to 23, LSR 24 to 26, and ASBR 27 to 29, and an Internet exchange (Internet eXchange / hereinafter referred to as “IX”) including ASBR 31 to 33. .) 30. Further, the own SP 10 and the external SP 20 are connected via the IX 30. The ASBRs 17 to 19 in the own SP 10 are adjacent to the external SP 20 via the IX 30, and the ASBRs 27 to 29 in the external SP 20 are adjacent to the own SP 10 via the IX 30.

  First, in the own SP 10, each of the routers 11 to 19 uses an OSPF (Open Shortest Path Find) protocol or a CSPF (Constrained-Based Shortest Path Find) protocol from each of the routers 11 to 19 to all the ASBRs 17 to 19. By collecting the remaining bandwidth information using the previously collected route information, the optimum route is calculated using the shortest route calculation algorithm such as the dijkstra algorithm. Alternatively, a centralized agent (not shown) that manages all the topology and bandwidth in its own SP 10 uses the OSPF protocol or the CSSF protocol to collect all routes from the routers 11 to 19 to the ASBRs 17 to 19 in advance. By collecting the remaining bandwidth information according to the information, the optimum route is calculated using the shortest route calculation algorithm such as the dijkstra algorithm.

  As a result, each of the routers 11 to 19 or the centralized agent holds the topology tree of the optimum route from each of the routers 11 to 19 to the ASBRs 17 to 19. Further, the ASBRs 17 to 19 can recognize which router is on the optimum route when the traffic passes through its own router by the topology tree.

  Next, in the external SP 20, each of the routers 21 to 29 uses the OSPF protocol or the CSSF protocol to the routers 21 to 29 from all the ASBRs 27 to 29, and also stores the remaining bandwidth information according to the path information collected in advance. By collecting, the optimum route is calculated using the shortest route calculation algorithm such as the dijkstra algorithm. Alternatively, a centralized agent (not shown) that manages all the topology and bandwidth in the external SP 20 uses the OSPF protocol or the CSSF protocol to collect the routes collected in advance from all the ASBRs 27 to 29 to the routers 21 to 29. By collecting the remaining bandwidth information according to the information, the optimum route is calculated using the shortest route calculation algorithm such as the dijkstra algorithm.

  As a result, each of the routers 21 to 29 or the centralized agent holds the topology tree of the optimum route from the ASBR 27 to 29 to each of the routers 21 to 29. Also, the ASBRs 27 to 29 can recognize which router is on the optimum route when the traffic passes through its own router by the topology tree.

  Next, the ASBRs 17 to 19 in the own SP 10 and the ASBRs 31 to 33 in the IX 30 exchange route information aggregated with each other using an eBGP (external Border Gateway Protocol). Similarly, the ASBRs 31 to 33 in the IX 30 and the ASBRs 27 to 29 in the external SP 20 exchange route information aggregated with each other using eBGP. In addition, the ASBRs 31 to 33 in the IX 30 exchange route information aggregated with each other by using iBGP (interior border gateway protocol). Here, the aggregated route information corresponds to aggregated Prefix information representative of the SP network, and an optimum border router is determined when an optimum route from the router in the own SP 10 to the router in the external SP 20 is set. Information that is necessary to do this. In this way, the ASBRs 17 to 19, 27 to 29, and 31 to 33 each acquire the aggregated route information, and therefore can grasp the routing destination without acquiring specific topology information.

  Then, by calculating the optimum route and exchanging the aggregated information described above, the optimum border router is determined from the ASBRs 17 to 19 in the own SP 10, and the optimum router is determined from the ASBRs 27 to 29 in the external SP 20. Also, abstraction information that is information on the start point router in the own SP 10, the end point router in the external SP 20, the optimum border router in the own SP 10, and the optimum border router in the external SP 20 is transmitted between the border routers. advertise. As a result, it is possible to set an optimum path from the router at the start point in the own SP 10 to the router at the end point in the external SP 20.

  Here, a case where the network administrator sets a path from the LER 13 that is the start point to the LER 21 that is the end point will be described with reference to FIG. By calculating the routes from the routers 11 to 19 to the ASBRs 17 to 19 and exchanging the aggregated route information, the optimum boundary router in the own SP 10 in the optimum route from the LER 13 that is the start point to the LER 21 that is the end point is the ASBR 19. It is determined that Further, the optimum border router in the external SP 20 is determined to be the ASBR 27 by calculating the routes from the ASBRs 27 to 29 to the routers 21 to 29 and exchanging the collected route information. Further, between the ASBRs 17 to 19 in the own SP 10, the ASBRs 31 to 33 in the IX 30 and the ASBRs 27 to 29 in the external SP 20, using the iBP protocol and the eBGP protocol, the LER (13, 21) of the start point and the end point is used. The abstract information of the set of boundary routers ASBR (19, 27) for is advertised to each other.

  As described above, by setting the optimum path from the LER 13 that is the start point to the LER 21 that is the end point according to the above-described procedure, the optimum in consideration of the network topology information and resources (bandwidth) in the network. Dynamic routes can be set dynamically. Also, by using RSVP-TE (Resource Reservation Protocol-Traffic Engineering) signaling, it is possible to set a traffic engineering path that takes into account resources in the network, and to dynamically set a connection link with an external SP. Can do.

  The ASBRs 17 to 19 which are the boundary routers in the SP 10 described above calculate the optimum path from the router at the starting point to the router in the SP 10 and hold it as topology tree information, and the boundary in the IX 30 Means for exchanging information aggregated with the ASBRs 31 to 33 as routers, and means for advertising the router information at the start and end points and the abstract information that is the optimum border router information. The ASBRs 27 to 29, which are boundary routers in the external SP 20, calculate the optimum route from the router to the terminal router in the external SP 20 and hold it as topology tree information, and the ASBR 31 in the IX 30. Means for exchanging information aggregated with .about.33, and means for advertising the router information at the start and end points and the abstract information which is the optimum border router information. Further, the ASBRs 31 to 33 in the IX 30 include means for exchanging information collected between the ASBRs 17 to 19 in the own SP 10 and the ASBRs 27 to 29 in the external SP 20. Actually, since it is necessary to set a bidirectional optimal route, the boundary router includes all of the means included in the boundary router in the local SP 10 and the means included in the boundary router in the external SP 20 described above.

  Next, a second embodiment will be described with reference to FIG. FIG. 4 is a schematic configuration diagram for explaining a case where information for confirming reachability to the router at the end point is exchanged between the boundary routers in the configuration in which the IX 30 illustrated in FIG. 3 does not exist. This communication system includes its own service provider network 50 (hereinafter referred to as “own SP50”) including LER 51 to 53, LSR 54 to 56, and ASBR 57 to 59, and an external including LER 61 to 63, LSR 64 to 66, and ASBR 67 to 69. Service provider network 60 (hereinafter referred to as “external SP 60”). The ASBRs 57 to 59 in the own SP 50 are adjacent to the external SP 60, and the ASBRs 67 to 69 in the external SP 60 are adjacent to the own SP 50. The own SP 50 and the external SP 60 are connected by ASBR 57 to 59 and ASBR 67 to 69, respectively.

  First, in the own SP 50, each of the routers 51 to 59 collects the remaining bandwidth information from the routers 51 to 59 using the OSPF protocol or the CSSF protocol to all the ASBRs 57 to 59 and the route information collected in advance. Thus, the optimum route is calculated using the shortest route calculation algorithm such as the dijkstra algorithm. Alternatively, a centralized agent (not shown) that manages all the topology and bandwidth in its own SP 50 uses the OSPF protocol and the CSSF protocol to collect all routes from the routers 51 to 59 to the ASBR 57 to 59 in advance. By collecting the remaining bandwidth information according to the information, the optimum route is calculated using the shortest route calculation algorithm such as the dijkstra algorithm.

  As a result, each of the routers 51 to 59 or the centralized agent holds the topology tree of the optimum route from each of the routers 51 to 59 to the ASBR 57 to 59. Also, the ASBRs 57 to 59 can recognize which router is on the optimum route when the traffic passes through its own router by the topology tree.

  Next, the ASBRs 57 to 59 in the own SP 50 and the ASBRs 67 to 69 in the external SP 60 are mutually aggregated and exchange route information using the eBGP protocol. As a result, the ASBRs 57 to 59 in the own SP 50 acquire the route information aggregated from the ASBRs 67 to 69 in the external SP 60, and thus grasp the routing destination without acquiring specific topology information in the external SP 60. be able to.

  The optimum border router is determined from the ASBRs 57 to 59 in the SP 50 by calculating the optimum route and exchanging the collected information. In this case, the border router in the adjacent external SP 60 connected to the optimum border router in the own SP 50 is guaranteed that the packet reaches the terminal router in the external SP 60. Also, abstract information, which is information for confirming reachability to the router that is the termination point in the external SP 60, is advertised between the ASBRs 57 to 59 and 67 to 69. As a result, it is possible to set an optimum path from the router at the start point in the own SP 50 to the router at the end point in the external SP 60.

  Here, a case where the network administrator sets a path from the LER 53 which is the start point to the LER 61 which is the end point will be described with reference to FIG. By the above-described route calculation from the routers 51 to 59 to the ASBRs 57 to 59 in the own SP 50 and the exchange of the collected route information, the optimum in the own SP 50 in the optimum route from the LER 53 that is the start point to the LER 61 that is the end point. The border router is determined to be ASBR59. Further, when the ASBR 59 which is the optimum border router is determined, the ASBR 59 is guaranteed that the packet arrives at the LER 61 via the ASBR 69 in the external SP 60. A set of boundary routers ASBR (59, 69) including the information for confirming reachability to the LER 61, which is the termination point in the external SP 60, between the ASBRs 59, 69 and the LER (53, 61) of the termination point. ) Abstract information.

  In this way, by setting an optimum route from the LER 53 that is the start point to the LER 61 that is the end point as necessary, the optimum route that takes into account the network topology information and the resources (bandwidth) in the network is moved. Can be set automatically. Furthermore, by using RSVP-TE signaling, it is possible to set a traffic engineering path taking into account resources in the network, and to dynamically set a connection link with an external SP.

  The ASBRs 57 to 59 which are the border routers in the SP 50 described above calculate the optimum route from the router at the starting point to the router in the SP 50 and hold it as topology tree information. Advertisement of abstract information, which is information for confirming reachability to the router at the end point, between the means for exchanging information aggregated between the ASBRs 67 to 69 that are border routers and the ASBR 67 to 69 in the external SP 60 Means. Further, ASBRs 67 to 69 which are border routers in the external SP 60 include means for advertising abstract information which is information for confirming reachability to the router at the end point. Actually, since it is necessary to set a bidirectional optimum route, the boundary router includes all of the means included in the boundary router in the local SP 50 and the means included in the boundary router in the external SP 60 described above.

  Further, ASBRs 17 to 19, 27 to 29, 31 to 33, 57 to 59, and 67 to 69, which are border routers according to the embodiments of the present invention, are configured by a computer in which software for executing processing by each means is incorporated. Is done. These software can be stored and distributed in a storage medium such as a magnetic disk (floppy disk, hard disk, etc.), optical disk (CD-ROM, DVD, etc.), semiconductor memory, etc. as a program that can be executed by a computer. . In addition, when one border router is provided with all of the means provided in the border router in its own SP and the means provided in the border router in the external SP, the border router similarly performs processing by these means. Consists of a computer with embedded software.

It is a schematic block diagram explaining the traffic at the time of advertising the service provider network by BGP conventionally. It is a schematic block diagram explaining the example which implement | achieves the path | route setting close | similar to an optimization path | route dynamically. It is a schematic block diagram explaining the case where abstract information is exchanged between border routers about 1st Embodiment. It is a schematic block diagram explaining the case where the information which confirms the reachability to the router of an end point is exchanged between border routers about 2nd Embodiment.

Explanation of symbols

1, 2, 10, 20, 50, 60 Service provider network 3, 4, 11-13, 21-23, 51-53, 61-63 Label edge router (LER)
5 to 8, 17 to 19, 27 to 29, 31 to 33, 57 to 59, 67 to 69 Autonomous system boundary router (ASBR)
14-16, 24-26, 54-56, 64-66 Label Switch Router (LSR)
30 Internet Exchange (IX)

Claims (6)

In a configuration in which a first network and a second network that conceal a specific topology are connected by a first border router and a second border router adjacent to each network, the first network A method for setting an MPLS traffic engineering path between the border routers when setting an optimal route from a starting point router to a terminal point router in a second network,
Calculate the optimal route from the starting point router to the first border router,
Calculate the optimal route from the second border router to the terminating router,
Between the first border router and the second border router, exchanging aggregate route information representing the network prefix;
Determining an optimum border router in the first network and an optimum border router in the second network based on the information of the optimum route and the aggregate route;
An optimum route setting method comprising exchanging abstract information including information on a start point router, a end point router, and an optimum border router between a first border router and a second border router. In a configuration in which a first network and a second network that conceal a specific topology are connected by a first border router and a second border router adjacent to each network, the first network A method for setting an MPLS traffic engineering path between the border routers when setting an optimal route from a starting point router to a terminal point router in a second network,
Calculate the optimal route from the starting point router to the first border router,
Between the first border router and the second border router, exchanging aggregate route information representing the network prefix;
Determining an optimum border router in the first network based on the information of the optimum route and the aggregate route;
The optimum boundary router in the second network capable of confirming the reachability to the start point router, the end point router, the optimum border router, and the end point router between the first border router and the second border router An optimum route setting method characterized by exchanging abstraction information consisting of the above information. Under the configuration where the networks that conceal a specific topology are connected by border routers adjacent to other networks, the optimal route from the router that is the starting point to the router that is the terminal point of the other network is set. In a router device provided as a border router for setting an MPLS traffic engineering path,
Means for calculating the optimum route from the router that is the starting point to its border router;
A means of calculating the optimum route from its border router to the router as the termination point;
Means for holding topology tree information of each optimum route;
Means for exchanging aggregate route information representing network prefixes with border routers of other networks;
Means for determining an optimum border router that constitutes an optimum route based on the topology tree information and the aggregated route information;
A router apparatus comprising: means for exchanging abstraction information including information on a starting point router, a terminal point router, and an optimum boundary router with another boundary router. Under the configuration where the networks that conceal a specific topology are connected by border routers adjacent to other networks, the optimal route from the router that is the starting point to the router that is the terminal point of the other network is set. In a router device provided as a border router for setting an MPLS traffic engineering path,
Means for calculating the optimum route from the router that is the starting point to its border router;
Means for holding topology tree information of the optimum route;
Means for exchanging aggregate route information representing network prefixes with border routers of other networks;
Means for determining an optimum border router that constitutes an optimum route based on the topology tree information and the aggregated route information;
Exchanging abstract information consisting of information on the optimum border routers of other networks that can confirm reachability to the origination point router, termination point router, the optimum border router, and the termination point router with other border routers And a router device. Under the configuration where the networks that conceal a specific topology are connected by border routers adjacent to other networks, the optimal route from the router that is the starting point to the router that is the terminal point of the other network is set. A program for setting an MPLS traffic engineering path.
In the computer constituting the border router,
A process of calculating the optimum route from the router that is the starting point to its border router;
The process of calculating the optimum route from its border router to the router as the termination point,
A process for holding topology tree information of each optimum route;
A process of exchanging aggregate route information representing a network prefix with a boundary router of another network;
A process of determining an optimum border router that constitutes an optimum route based on the topology tree information and the aggregated route information;
An optimum route setting program that executes processing for exchanging abstract information including information of a start point router, a end point router, and an optimum border router with another border router. Under the configuration where the networks that conceal a specific topology are connected by border routers adjacent to other networks, the optimal route from the router that is the starting point to the router that is the terminal point of the other network is set. A program for setting an MPLS traffic engineering path.
In the computer constituting the border router,
A process of calculating the optimum route from the router that is the starting point to its border router;
Processing to retain topology tree information of the optimum route;
A process of exchanging aggregate route information representing a network prefix with a boundary router of another network;
A process of determining an optimum border router that constitutes an optimum route based on the topology tree information and the aggregated route information;
Exchanging abstract information consisting of information on the optimum border routers of other networks that can confirm reachability to the origination point router, termination point router, the optimum border router, and the termination point router with other border routers The optimal route setting program that executes the processing to be performed.

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