3Com 10014299 manual RouterA display ospf peer, RouterD display ospf peer

OSPF Configuration Example 443

Run display ospf peer on Router A to show OSPF peer. Note that Router A has 3 peers.

[RouterA] display ospf peer
Peer	pri	State	Address	Interface
4.4.4.4	1	full/DRother	192.1.1.4	Ethernet0
3.3.3.3	2	full/BDR	192.1.1.3	Ethernet0
2.2.2.2	0	full/DRother	192.1.1.2	Ethernet0

The status of every peer is full, which means that Router A has created neighboring relation with all peers. Only DR and BDR have created neighboring relation with all routers on the network. Router A is DR and Router C is BDR on the network. All other peers are DRother, which means that they are neither DR nor BDR.

Change the preference of Router B to 200:

[RouterB-Ethernet0] ospf dr-priority 200

Run display ospf peer on Router A to show OSPF peers. Note that the preference of Router B has been changed to 200, but it is not DR.

[RouterA] display ospf peer
Peer	pri	State	Address	Interface
4.4.4.4	1	full/DRother	192.1.1.4	Ethernet0
3.3.3.3	2	full/BDR	192.1.1.3	Ethernet0
2.2.2.2	200	full/DRother	192.1.1.2	Ethernet0

Only when the DR no longer exists on the network are the DR changed. Shut down Router A and run display ospf peer on Router D to display peers. Note that Router C, which was BDR, now becomes DR and so does Router B.

[RouterD] display ospf peer
Peer	pri	State	Address	Interface
3.3.3.3	2	full/BDR	192.1.1.3	Ethernet0
2.2.2.2	200	full/DR	192.1.1.2	Ethernet0

Shutting down the router and restarting leads to the reelection of DR and BDR. Restart router A and run the display ospf peer command to display peers. Note that router B is elected DR (whose preference is 200) and Router A becomes BDR (whose preference is 100).

[RouterD] display ospf peer
Peer	pri	State	Address	Interface
1.1.1.1	100	full/BDR	192.1.1.1	E0
3.3.3.3	2	full/DRother	192.1.1.3	E0
2.2.2.2	200	full/DR	192.1.1.2	E0