JP5130022B2 - Route information management device - Google Patents

Description

  The present invention relates to a route information management apparatus that manages route information of a network.

  The Internet is configured by connecting a large number of networks called AS (Autonomous System) that perform routing and the like based on a common policy. In order to enable communication from a computer belonging to a certain AS to a computer belonging to another certain AS, route information indicating how each AS is connected to another AS is necessary. This route information is exchanged between ASs using BGP (Border Gateway Protocol).

  Here, when performing communication from a computer belonging to a certain AS to a computer belonging to another certain AS, it is required to perform communication by selecting an optimum route. For this purpose, in recent years, it has been proposed to calculate an optimum route by using a protocol called PCE (Path Computation Element) (for example, see Non-Patent Documents 1 and 2). In PCE, a network device (router) called a path calculation server is provided in each AS, and an optimum route is calculated by this path calculation server. At this time, the path calculation server of each AS needs to know the address of the adjacent AS path calculation server corresponding to the route to the computer that is the communication destination.

As a method for acquiring the address of the path calculation server, for example, a method that uses a procedure for checking whether or not the router supports the function as the path calculation server before exchanging route information by BGP has been proposed. (For example, see Non-Patent Document 3).
J. Ash, et al., "Path Computation Element (PCE) Communication Protocol Generic Requirements", IETF RFC4657, September 2006. JP. Vasseur, et al., "Path Computation Element (PCE) communication Protocol (PCEP)", IETF Internet Draft, July 2007. Vijayanand, et al., "BGP Protocol extensions for PCE Discovery across Autonomous systems", IETF Internet Draft, July 2007.

  However, in the path calculation server address acquisition method proposed in Non-Patent Document 3, it is necessary to change the BGP protocol so that a procedure for confirming non-correspondence to the path calculation server function is first performed. For this reason, it is necessary to upgrade the function (software) of the router, which causes a problem that the operation cost of the network increases. In addition, if there is a router that does not support the path calculation server function in the middle, there is also a problem that it becomes impossible for the path calculation server to appropriately acquire the addresses of other path calculation servers.

  The present invention has been made in view of the above points, and an object thereof is to make it possible to reliably acquire the address of a path calculation server without changing the BGP protocol.

  The present invention has been made to solve the above-described problem, and is a route information management device for exchanging and managing route information of a network configured by connecting a plurality of domains to each other. And a transmission means for transmitting a self-address indicating that it is a transmission destination of a route calculation request for obtaining a corresponding optimum route to a route information management device in another adjacent domain together with the route information, Is a path information management device.

  In the present invention, the route information management device is a device that manages route information of the network and is a device (path calculation server) that is a transmission destination of the route calculation request, and other than its own address indicating the transmission destination. When transmitting to the route information management apparatus, the address is transmitted together with the route information. Therefore, the other route information management device can acquire the address (that is, the address of the path calculation server) to which the route calculation request is transmitted in addition to acquiring the route information (according to BGP as usual). .

  According to the present invention, in the route information management device, storage means for storing the route information and the address associated with each other transmitted from the first other route information management device, and second other route information A route calculation request that receives the route calculation request from the management device, searches the storage means for an address corresponding to the destination of the route calculation request, and transmits the route calculation request to the route information management device having the searched address Means.

  In this invention, the route information management device (path calculation server) stores route information and addresses, and when a route calculation request is received, the route information management device (path calculation server) of the address obtained by appropriately searching for the address. Send a route calculation request to Therefore, the route is correctly calculated and the optimum route can be obtained.

  According to the present invention, it is possible to reliably acquire the address of the path calculation server without changing the BGP protocol.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram illustrating a network configuration to which a route information management device according to an embodiment of the present invention is applied. This network includes an AS 100 that is an AS (domain) to which the client A (computer having a communication function) belongs, and an AS 200 that is an AS (domain) to which the client B (computer having the communication function) with which the client A communicates. And an AS 300 that is an AS of the communication carrier.

  The AS 100 includes a path calculation server PCE1 (route information management device), and this path calculation server PCE1 acquires and holds the route information of this network as described below.

  The AS 300 includes path calculation servers PCE2 and PCE3 (route information management device) and one or more routers. The path calculation servers PCE2 and PCE3 and each router acquire and hold the route information of this network in the same manner as the path calculation server PCE1.

  The AS 200 includes a path calculation server PCE4 (route information management device), and this path calculation server PCE4 similarly acquires and holds the route information of this network.

  Further, the AS 100 and the AS 300 are connected by the path calculation servers PCE1 and PCE2, and the AS 300 and the AS 200 are connected by the path calculation servers PCE3 and PCE4.

  Here, in each AS100, AS200, and AS300, routing using a routing protocol such as OSPF (Open Shortest Path Fast) is performed as appropriate. Therefore, for example, the client A in the AS 100 can communicate with other computers in the AS 100 using the above routing protocol, and when communicating with a computer outside the AS 100, the path that holds the route information and functions as a router. Communication with the outside is made possible via the calculation server PCE1.

  FIG. 2 is a diagram for explaining how the path calculation servers PCE1, PCE2, PCE3, and PCE4 perform communication based on BGP in order to exchange route information. Here, in order to enable communication from the AS 100 or AS 300 to the client B of the AS 200, a case where the address of the client B is advertised as route information will be described as an example.

  First, the path calculation server PCE4 of the AS 200 to which the client B belongs transmits the address (route information) of the client B to the router that is its connection partner, that is, the path calculation server PCE3. At this time, the path calculation server PCE4 informs that the destination to which the path calculation server PCE3 transmits a route calculation request (described later) for obtaining the optimum route to the client B is itself (the path calculation server PCE4). In addition to the above route information, its own address is simultaneously transmitted to the path calculation server PCE3. The path calculation server PCE3 of the AS 300 that has received these pieces of information knows that it is only necessary to transmit a route calculation request to the path calculation server PCE4 when transmitting a route calculation request to obtain an optimum route to the client B. Can do.

  Although not shown, the path calculation server 3 (the same applies to the path calculation servers PCE2 and PCE1 described below) also receives the path information about the client B from the other AS path calculation servers and the other AS. The address of the path calculation server may be received. In this case, there are a plurality of candidates for the path calculation server PCE3 to transmit the route calculation request, and the path calculation server PCE3 may select any one as appropriate and transmit the route calculation request. Similarly, other clients belonging to the AS 200 other than the client B have obtained the path information and the address of the corresponding path calculation server, and the path calculation server PCE3 (the same applies to the path calculation servers PCE2 and PCE1). The path calculation server is determined according to the client for which the optimum route is to be obtained, and a path calculation request is transmitted to the determined path calculation server.

  The conventional simple BGP uses a procedure for transmitting only path information (client B address) from the path calculation server PCE4 to the path calculation server PCE3 for the purpose of enabling routing between ASs. In the present invention, as described above, the route information and the address of the path calculation server are simultaneously transmitted by simply adding the address of the path calculation server in the simple BGP procedure. Accordingly, there is an advantage that it is not necessary to change the BGP protocol as in Non-Patent Document 3 described above. Even if the path calculation server PCE3 does not have the function of the path calculation module 20 (to be described later) (that is, a router that supports only simple BGP), the path calculation server address only needs to be discarded, and only the route information is present. Can be acquired.

  The path calculation server PCE3 of the AS 300 that has received the above information from the path calculation server PCE4 transmits the address of the client B to the path calculation server PCE2. Similarly to the above, in order to inform that the path calculation server PCE2 transmits the path calculation request for obtaining the optimum path to the client B is itself (path calculation server PCE3), the path calculation server PCE2 Are simultaneously transmitted to the path calculation server PCE2.

  Further, the path calculation server PCE2 that has received the above information from the path calculation server PCE3 transmits the address of the client B to the router that is its connection partner, that is, the path calculation server PCE1. Similarly, in order to notify that the transmission destination of the path calculation request for the path calculation server PCE1 to obtain the optimum path to the client B is itself (path calculation server PCE2), the path calculation server PCE1 and the path calculation server PCE1 The address is also transmitted to the path calculation server PCE1 at the same time.

  In this way, each path calculation server PCE3, PCE2, PCE1 acquires the address of the path calculation server of the adjacent AS, so that the path calculation server to which the path calculation request should be transmitted in order to obtain the optimum path to the client B is obtained. I can grasp it.

  Next, an outline of a method for obtaining the optimum route from the client A to the client B in a state where each of the path calculation servers PCE1, PCE2, PCE3, and PCE4 has acquired the route information and the address of the necessary path calculation server as described above. Will be explained.

  In FIG. 3, first, the client A transmits a route calculation request to the path calculation server PCE1 in the same AS 100. This route calculation request includes information indicating that the routing destination is the client B. When the path calculation server PCE1 receives the route calculation request, the path calculation server PCE1 searches for a path calculation server corresponding to the client B from the list of held path calculation servers. Here, since the path calculation server PCE2 is found by the search, the path calculation server PCE1 transmits a route calculation request to the path calculation server PCE2. The path calculation servers PCE2 and PCE3 repeat the same operation, and reach the path calculation server PCE4 of the same AS 200 as the client B to which the route calculation request is the destination.

  Then, the path calculation server PCE4 refers to the stored route information, finds the optimum route from the client A to the client B, and transmits the result as a route calculation response to the path calculation server PCE3. The route calculation response is sent to the client A by sequentially tracing the path calculation servers PCE3, PCE2, and PCE1. As a result, routing from the client A to the client B by the optimum route becomes possible.

Next, a specific configuration and operation of the path calculation server will be described with reference to FIG.
The path calculation server includes a BGP module 10 and a path calculation module 20. The BGP module 10 communicates with other path calculation servers or routers using BGP to acquire and hold network path information and the address of the AS path calculation server adjacent to the network. The path calculation module 20 receives a path calculation request from another path calculation server, searches the BGP module 10 for the path calculation server, and transmits the path calculation request to the obtained path calculation server.

  More specifically, the operation procedure of the path calculation server will be described. First, the BGP module 10 acquires and holds the path information and the address of the path calculation server by BGP ((1) in the figure). At this time, the addresses of one or a plurality of path calculation servers are associated and held for each client in the network. Thereafter, when there is a route calculation request from another path calculation server, the path calculation module 20 receives the route calculation request ((2) in the figure) and grasps the routing destination from the route calculation request. Then, the path calculation module 20 searches the BGP calculation module 10 for the path calculation server corresponding to the destination ((3) in the figure), and acquires the address of the path calculation server to which the route calculation request is to be transmitted ((4) in the figure). ). The path calculation module 20 that has acquired the address of the path calculation server transmits a route calculation request to the path calculation server of the address ((5) in the figure).

  As described above, the embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to the above, and various design changes and the like can be made without departing from the scope of the present invention. It is possible to

  For example, the present invention can correspond to IPv4 (Internet Protocol version 4), IPv6 (Internet Protocol version 6), VPNv4 (Virtual Private Network version 4), VPNv6 (Virtual Private), and so on as route information. .

  Further, the BGP module 10 and the path calculation module 20 of the path calculation server can be realized by causing a computer to read a program that executes each of the above functions as appropriate.

It is the figure which showed the structure of the network with which the route information management apparatus by one Embodiment of this invention is applied. It is a figure explaining a mode that the path calculation server performs communication based on BGP in order to exchange route information. It is a figure explaining the outline of the method of calculating | requiring the optimal path | route from the client A to the client B in the network of FIG. It is a figure explaining a structure and operation | movement of a path | pass calculation server.

Explanation of symbols

  AS100, AS200, AS300 ... autonomous system (domain) PCE1, PCE2, PCE3, PCE4 ... path calculation server (route information management device) 10 ... BGP module 20 ... path calculation module

Claims (1)

A route information management device for managing route information of a network configured by connecting a plurality of domains to each other,
In the BGP procedure, another address in which a self-address indicating that it is a transmission destination of a route calculation request for obtaining an optimum route according to the destination is added to the route information and the address is adjacent to the route information. Transmitting means for transmitting to the route information management device of
Storage means for storing the path information transmitted from the first other path information management device in association with the address;
Upon receiving the route calculation request from the second other route information management device, the address corresponding to the destination related to the route calculation request is searched from the storage means, and the route calculation is performed to the route information management device having the searched address. A route calculation request means for transmitting the request;
A route information management device comprising:

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