CCENT/CCNA ICND1 100-101 Official Cert Guide

Configuring the OSPF Router ID

Designated Routers

While OSPF has many other optional features, most enterprise networks that use OSPF choose to configure each router’s OSPF router ID. OSPF-speaking routers must have a Router ID (RID) for proper operation. By default, routers will choose an interface IP address to use as the RID. However, many network engineers prefer to choose each router’s router ID, so command output from commands like show ip ospf neighbor lists more recognizable router IDs.

To find its RID, a Cisco router uses the following process when the router reloads and brings up the OSPF process. Note that when one of these steps identifies ...