[c-nsp] Newbish OSPF DR question on VLANs

[Hank Nussbacher]

At 11:48 AM 07-06-07 +0300, Hank Nussbacher wrote:

PNG did not make it thru so you can find it here:
http://www.interall.co.il/vlans.png

Thanks,
Hank

>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
>
>_______________________________________________
>cisco-nsp mailing list  cisco-nsp at puck.nether.net
>https://puck.nether.net/mailman/listinfo/cisco-nsp
>archive at http://puck.nether.net/pipermail/cisco-nsp/