ABSTRACT
This chapter focuses on the Link State Database (LSDB) structure of routing domains containing a single area, but possibly connected to other routing domains. It introduces the basic elements of the OSPF and IS-IS LSDBs. The chapter explains how routers and links are identified, and how links are typified. It presents the general structure of the LSDB elements. The chapter discusses how these elements are used to describe the topological and domain-internal addressing information in OSPFv2, in IS-IS, and in OSPFv3. It examines the representation of the domain-external addressing information. The chapter describes the representation of the link information, and also focuses on the Link State Advertisements and Link State Protocol Data Units needed to describe a single-area network. The network representation requires suitable router and link identifiers. The link types are abstractions of the actual link technologies for the purpose of network representation.
