Method and router for synchronizing link state advertisement

Abstract

The invention relates to the technical field of network communication and discloses a method and a router for synchronizing link status broadcasting, wherein, the method includes the following steps: first, link status broadcast corresponding to the highest local current priority is acquired and the corresponding category of link status broadcast of the neighboring router is collected; the link status broadcast message of the neighboring router is acquired when the corresponding category of link status broadcast is what the local link status database lacks or the information updated by the neighboring router. The method and the router of the invention ensure that the router carries out inter-area communication within a shorter period, and re-generates complete category 1 and category 2 LSA information after the synchronization of the category 1 and category 2 LSA information, therefore, the calculating result on the router in the area is relatively complete.

Description

technical field [0001] The invention relates to the technical field of network communication, in particular to a method and a router for synchronizing link state broadcasts. Background technique [0002] Open Shortest Path First (OSPF, Open Shortest Path First) is a link state protocol, which describes the link state through Link State Advertisement (LSA, Link State Advertise), and the collection of LSA is called the link state database ( LSDB, link state database). There are 9 types of LSAs specified in the OSPF protocol. They are: Router LSA, Network LSA, Summary-3 Link State Broadcast (Summary-3LSA), Summary-4 Link Link state advertisement (Summary-4LSA), external link state advertisement (External LSA), non-pure area link state advertisement (NSSA LSA), type 9 link state advertisement (Type 9 LSA), type 10 link state advertisement ( Type 10 LSA) and Type 11 Link State Advertisement (Type 11 LSA). The OSPF protocol defines Router LSAs as Type 1 LSAs, Network LSAs as Ty...

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Problems solved by technology

[0005] The above prior art is to send all the LSAs of the local LSDB to the neighbors through the DD message, and then request the neighboring routers for the LSAs not included in the local LSDB, until the LSDBs of the two parties are consistent, it means that the LSDBs between the routers have been synchronized, so It will take a long time to synchronize the LSDB. According to the statistical data, it takes about 20 minutes for the existing technology to synchronize the LSA generated by 200,000 routes, and only after the synchronization is completed, the Router LSA can be regenerated, and there is no regenerated The Router LSA cannot calculate the route in the area, then the router cannot communicate in the area, and the communication interruption for such a long time is unbearable

In actual application, there may be more routers, and more external routes are imported, so it will take longer to achieve LSDB synchronization between routers

[0006] In addition, the Router LSA and Network LSA generated before the neighbor relationship reaches the FULL state in the above-mentioned prior art are incomplete, for example: in point-to-point (P2P, Point to Point) or point-to-multipoint (P2MP, Point to Multi- Point) on the link, if the neighbor relationship has not reached the FULL state, a pure link (Stub Link) will be generated when the Router LSA is generated, and a P2P Link will be added when the FULL state is reached; in the broadcast (Broadcast) or Non-Broadcast Multi-Access (NBMA, Non-Broadcast Multi-Access) link, if the FULL state is not reached, a Stub Link will be generated when the Router LSA is generated, and a Transit will be generated when the FULL state is reached Link: When a router generates a Network LSA, it needs to be completely adjacent to at least one router on the network before generating the LSA, that is, the attached routers (Attached Routers) only contain neighbors that reach the FULL state

According to RFC2328, the attached router on P2P Link, Transit Link and Network LSA is very important for route calculation. If the information is incomplete, the calculation result of intra-area route will be incomplete, which will cause some routers to can't communicate

[0007] To sum up, routers in the prior art need a long time to perform intra-area communication, and the Router LSA and Network LSA information generated before the neighbor relationship reaches the FULL state is incomplete

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