OSPF and IS-IS: Choosing an IGP for Large-Scale Networks

Chapter 6. Link State Database Synchronization

I have said it many times already, and I will say it again: The key concept behind link state routing protocols is that each router in an area performs localized route calculations based on information in a common topological database. It is therefore essential that every router in an area have exactly the same topological database. This is the purpose of link state database synchronization. Whenever a router becomes active on an OSPF or IS-IS network, it must synchronize its database with its neighbors to guarantee that they are the same. If the router becomes active on a point-to-point link, it synchronizes with the neighbor at the other end of the link. If it becomes active on a multi-access ...