OSPF Complete Implementation

Book excerpt: Written by the creator of the OSPF (Open Shortest Path First) protocol, this book demonstrates the protocol in action with a complete OSPF implementation. It shows how the protocol's theory is realized in a real-time distributed software system, reveals many of the finer points of OSPF, and offers experienced-based optimization and porting techniques. The implementation described and examined in this book is written in C++ and designed with porting in mind. The book details the software architecture of the implementation and describes in-depth key OSPF functions, illustrated by numerous code samples. It also includes a guide to porting OSPF software to different environments, with an explanation of the software layer between the OSPF implementation and the operating system. In addition, two sample ports are included-a routing daemon for Linux and an OSPF routing simulator for Linux and Windows. Key topics covered include: Implementation architecture, including I/O, data flow, and data structures Porting considerations, including handling different types of CPU chips AVL trees, Patricia trees, priority queues, timers, and logging messages The IP routing table Link-state database, including aging LSAs Neighbor discovery and the neighbor state machine Synchronization of link-state databases through the flooding algorithm Hierarchy Routing calculations, including intra-area, inter-area, and external routes An implementation of the Multicast Extensions to OSPF (MOSPF) Configuration and monitoring, including cryptographic authentication Host wiretapping Together, OSPF: Anatomy of an Internet Routing Protocol and OSPF Complete Implementation provide an in-depth view into the theory and inner workings of OSPF, and the knowledge you need to make full use of this important protocol in Internet-based applications.