OSPF interface priority is a configurable value that influences which router becomes the designated router (DR) or backup designated router (BDR) on a broadcast segment. The default is 1; the highest priority wins, and the highest router ID breaks ties. section 18.3.2
Key operational rules:
- Configure ip ospf priority 0 to prevent an interface from becoming the DR or BDR. section 18.3.2
- Expect existing DR and BDR roles to remain unchanged after a priority increase; reset the OSPF process to trigger a new election. section 18.3.2
Raising an interface's priority
R2(config)# interface g0/1 R2(config-if)# ip ospf priority 100 R2(config-if)# do show ip ospf interface g0/1 ... State DROTHER, Priority 100 R2 does not immediately become DR because the election already occurred. After resetting the process, the higher priority can affect the new election.
