Enhancing the network scalability of link-state routing protocols by reducing their flooding overhead

We consider scalability issues of routing protocols for large-scale networks. Link-state routing protocols play an important role in generalized multiprotocol label switching (GMPLS) networks based on photonic technologies as well as in conventional packet-based IP networks. The scalability of a link-state routing protocol mainly depends on the overhead of protocol-related messages, which are disseminated by flooding. We propose ways to reduce this overhead in link-state routing protocols such as OSPF and IS-IS, and also present extensions to OSPF that provide support for our techniques. The basic approach is to limit the sets of neighboring nodes in the flooding of link-state information, while maintaining reliability in the distribution of link-state information. We also report on extensive simulation to evaluate the performance of our algorithm in terms of reducing the flooding overhead. Our algorithm provides improved network scalability as well as efficient and reliable convergence of routing information.