Networks And Neighbors; Router Types - Dell Force10 Z9000 Configuration Manual

Networks and Neighbors

As a link-state protocol, OSPF sends routing information to other OSPF routers concerning the state of the links between them. The
state (up or down) of those links is important.
Routers that share a link become neighbors on that segment. OSPF uses the Hello protocol as a neighbor discovery and keep alive
mechanism. After two routers are neighbors, they may proceed to exchange and synchronize their databases, which creates an
adjacency.

Router Types

Router types are attributes of the OSPF process.
A given physical router may be a part of one or more OSPF processes. For example, a router connected to more than one area,
receiving routing from a border gateway protocol (BGP) process connected to another AS acts as both an area border router and an
autonomous system router.
Each router has a unique ID, written in decimal format (A.B.C.D). You do not have to associate the router ID with a valid IP address.
However, to make troubleshooting easier, Dell Networking recommends that the router ID and the router's IP address reflect each
other.
The following example shows different router designations.
488
Open Shortest Path First (OSPFv2 and OSPFv3)