Based Terabit Router Ospf Routing Protocol Improvements

The Internet is growing rapidly in both size and traffic load. The number of routers in a routing domain is becoming larger. And link failures, recoveries or changes also appear more frequently. Slow Convergence, increasing routing table and bad stability are the major issues in the Internet. These weaken present routing system and the QoS of the Internet.OSPF is a link state routing protocol, it maintains a database describing the entire network topology of the domain, and uses this database to calculate the shortest paths to all the nodes in that network. Open Shortest Path First (OSPF) protocol is one of the most widely deployed intra-domain routing protocols in the Internet. The researches to improve the stability and convergence of OSPF are valuable.This dissertation is based on the National 863 plan specialized research project, the research of an Extensible to Terabit High Performance IPv4/v6 Router platform and experimental system. The context of this paper is focused on the research and implementation to improve the stability and convergence of the OSPF routing protocol which will operate on the Terabit core router.The detailed contents are summarized as below:1. The Hello protocol in OSPF is responsible for establishing and maintaining neighbor relationships. OSPF uses Link State Advertisements (LSAs) to exchange the database information between routers. After synchronization of the database, OSPF uses Dijkstra's Shortest Path First (SPF) algorithm to find the shortest path to all nodes.The focus of research should be on the Hello running, link state database synchronizing and SPF algorithm.2. Analyze the Hello protocol and give its disadvantageous affects to the convergence and stability, then give the improvement consideration. The major consideration is to speed up the Hello process and reduce the cause result the changes of the network. Base on this, design a quick session scheme and a graceful shutdown scheme.3. Analyze the SPF protocol and give its disadvantageous affects to the convergence and stability, then give the improvement consideration. The major consideration is to save up the SPF computation process and reduce the SPF computation times. Base on this, design an incremental SPF and a SPF computation throttling scheduling shutdown scheme.4. Analyze the architecture of Terabit router and the characters of the implementation of OSPF, confirm function-oriented module architecture for the implementation.Analyze protocol data flow, packets flow and operations flow, give a multi-thread queues based on the prioritized scheduling scheme.Then give the detailed implementation of the Hello protocol and the SPF computation.5. Design and execute the test scheme for the implementation of OSPF,analyze the testing result,prove that the improvements in this paper are fulfilled, the whole conformance is perfect.