OSPF State

Chris Knight

Example;
[SanJose# show ip ospf interface fastethernet1/0
FastEthernet1/0 is up, line protocol is up
Internet Address 140.100.17.129/28, Area 3
Process ID 100, Router ID 140.100.32.10, Network Type BROADCAST, Cost: 1
Transmit Delay is 1 sec, State DR, Priority 100
Designated Router (ID) 140.100.32.10, Interface address 140.100.17.129
Backup Designated router (ID) 140.100.23.1, Interface address 140.100.17.130
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Hello due in 00:00:06
Neighbor Count is 3, Adjacent neighbor count is 2
Adjacent with neighbor 140.100.17.132
Adjacent with neighbor 140.100.17.131
Adjacent with neighbor 140.100.23.1 (Backup Designated Router)]

Now according to the exerpt on the BSCI book, in this example this router is the BDR on the ethernet segment fto which the E0 int is connected.
That part I understand as the BDR int address is in the same network.

However looking at the Internet address and the state DR, wouldnt this router be the DR for this segment?

Can you have a router function as both a DR/BDR for the same segment? I didnt think that was possible.

Plazma

you are correct in that DR state means that the router is the DR..

You will always have a DR , but not always a BDR(on non P2P links). So a router that is a DR will never be the BDR unless parameters are changed and the OSPF process is reset.

Chris Knight

Thanks for the reply. Perhaps the book is wrong in this sense?

It wouldnt be the first time, but I dont know. Hence the asking

Plazma

I use books with a grain of salt.. and ALWAYS use multiple resources.. when in doubt, check the Cisco IOS docs.. they are *and should be* the most accurate information on the web.