[c-nsp] Newbish OSPF DR question on VLANs

[Rodney Dunn]

Also depends if you have the priority set and who came up first.

What is the uptime of C?

On Thu, Jun 07, 2007 at 11:48:52AM +0300, Hank Nussbacher wrote:
> What causes a router to become a Designated Router (DR) on a VLAN?  I 
> always thought highest router-id, but I have a few test routers and here is 
> what I get:
> 
> C#sho ip ospf nei
> 
> Neighbor ID     Pri   State           Dead Time   Address         Interface
> 192.168.1.1       1   FULL/DR         00:00:37    10.1.3.1        Vlan50
> 192.168.1.3       1   FULL/DR         00:00:38    10.3.3.1        Vlan40
> 192.168.1.2       1   FULL/DR         00:00:30    10.2.2.2        Vlan30
> C#sho ip ospf neigh 192.168.1.1 ?
> C#sho ip ospf neigh 192.168.1.1 deta
>  Neighbor 192.168.1.1, interface address 10.1.3.1
>     In the area 0 via interface Vlan50
>     Neighbor priority is 1, State is FULL, 6 state changes
>     DR is 10.1.3.1 BDR is 10.1.3.2
>     Options is 0x52
>     LLS Options is 0x1 (LR)
>     Dead timer due in 00:00:34
>     Neighbor is up for 00:27:35
>     Index 1/1, retransmission queue length 0, number of retransmission 1
>     First 0x0(0)/0x0(0) Next 0x0(0)/0x0(0)
>     Last retransmission scan length is 1, maximum is 1
>     Last retransmission scan time is 0 msec, maximum is 0 msec
> C#sho ip ospf neigh 192.168.1.2 deta
>  Neighbor 192.168.1.2, interface address 10.2.2.2
>     In the area 0 via interface Vlan30
>     Neighbor priority is 1, State is FULL, 6 state changes
>     DR is 10.2.2.2 BDR is 10.2.2.1
>     Options is 0x52
>     LLS Options is 0x1 (LR)
>     Dead timer due in 00:00:31
>     Neighbor is up for 00:27:49
>     Index 3/3, retransmission queue length 0, number of retransmission 0
>     First 0x0(0)/0x0(0) Next 0x0(0)/0x0(0)
>     Last retransmission scan length is 0, maximum is 0
>     Last retransmission scan time is 0 msec, maximum is 0 msec
> C#sho ip ospf neigh 192.168.1.3 deta
>  Neighbor 192.168.1.3, interface address 10.3.3.1
>     In the area 0 via interface Vlan40
>     Neighbor priority is 1, State is FULL, 6 state changes
>     DR is 10.3.3.1 BDR is 10.3.3.2
>     Options is 0x52
>     LLS Options is 0x1 (LR)
>     Dead timer due in 00:00:37
>     Neighbor is up for 00:28:02
>     Index 2/2, retransmission queue length 0, number of retransmission 1
>     First 0x0(0)/0x0(0) Next 0x0(0)/0x0(0)
>     Last retransmission scan length is 1, maximum is 1
>     Last retransmission scan time is 0 msec, maximum is 0 msec
> 
> IOS 12.3(11)T2 if it makes a difference.
> 
> All four of them become DR.  I have attached a png file that I hope makes 
> it thru the Mailman filter.
> 
> Thanks,
> -Hank

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