This chapter and the following about BGP constitute the heart of this book. Based on the discussion of kernel and static routes in the previous chapters, this chapter introduced the features and flexibility of dynamic routing protocols. Intrinsic characteristics of link-state and distance-vector protocols were discussed, and complex lab scenarios were developed to demonstrate RIPv2, OSPF, and IS-IS behavior and their interaction with the UNIX kernel table, static routes, and connected interface routes. The following chapter covers BGPv4, a path-vector routing protocol specialized in interdomain signaling that relies on IGPs for forwarding paths.