Create link status data packets

Once the router of The Link Status data packet is created, the link status data packet (LSP) can be created, which contains the link status information related to the link. (LSP includes link type, IP address, subnet mask, and overhead) Flood link status data packets to neighbors: www.2cto.com each vro floods its link status information to all other link status vrouters in the routing area. Once the router receives the LSP from the neighboring router, it immediately sends the LSP from all interfaces except the interfaces that receive the LSP. This process forms the LSP flooding effect on all routers in the entire routing area. LSP does not need to be sent regularly, but must be sent only in the following cases:
L during the initial start of the vro or during the start of the route protocol process on the vro l each time the topology changes, including link connection or disconnection, in addition to link status information, LSP also contains other information (such as serial number and expiration information) to help manage the flood process. Each vro uses this information to determine whether the LSP has been received from another vro and whether the LSP has any update information not found in the link information database. This process allows the router to retain only the latest information in its link status database. Build a link status database: after each vro uses the link status flooding process to spread its own LSP, each vro will have an LSP from all vrouters in the entire routing area. These LSPs are stored in the link status database. At present, each router in the routing area can use the SPF algorithm to build the SPF tree you have learned before. With the complete link status database, you can use the database and SPF (Shortest Path First) algorithm to calculate the preferred path (Shortest Path) to each network ).
Advantages of the link status Routing Protocol: When you create a topology, the link status Routing Protocol creates a topology (SPF tree) of the network structure. The link status routing protocol exchanges the link status information, therefore, the SPF algorithm can build an SPF tree for the network. With the SPF tree, Each router can independently determine the shortest path to each network. After www.2cto.com quickly converges to receive a link status packet (LSP), the link status routing protocol immediately floods the LSP from all interfaces except the interfaces that receive the LSP. After the initial LSP flooding, the link status Routing Protocol issues LSP only when the topology changes. This LSP only contains information related to the affected link. The link status routing protocol does not send updates on a regular basis. (Note: The OSPF router will flood its own link status every 30 minutes. This is called Force update .) The hierarchical design of The Link Status routing protocol (such as OSPF and IS-IS) uses the principle of the region .. A hierarchical network structure is formed in multiple regions, which facilitates route aggregation (Summary) and isolates Routing Problems in one region.
Link Status Routing Protocol requirements modern link status routing protocol design is designed to minimize the impact on memory, CPU and bandwidth. You can use and configure multiple zones to reduce the link status database. By dividing multiple regions, you can also limit the number of link state information of flood in the routing domain, and only send LSP to the required router. (That is to say, it is okay to send the API to other routers .) Compared with the distance vector routing protocol, the link status Routing Protocol generally requires more memory, CPU computing, and bandwidth. The memory requirement comes from the need to use the link status database and create an SPF tree. Compared with the distance vector routing protocol, the link status routing protocol may require more CPU computing. Compared with the Bellman-Ford equi-distance vector algorithm, the SPF algorithm requires more CPU time because the link status Routing Protocol creates a complete topology. Bandwidth requires that packet flooding in the link status will negatively affect the available bandwidth of the network. This should only occur during the initial startup of the vro, but it may also cause problems in the unstable network.