OSPF Convergence/ CDP issue

[terrencepayet]

Hi Experts,

There's a problem that's driving me crazy for the past 2 days.

I cant seem to get OSPF to work on one router Site D(see network diagram).

It doesn't form any adjacency with the neighbouring router.

I have check the area and subnet mask to make sure is the same as neighbouring router.

I can ping the neighbouring interface with no problem.

I've attached my debug ip ospf adj log.

The other thing that i find it strange is that when i run the sh cdp n command from site D, nothing comes up.

Really apreciate if you guys can help.

many thanks.

[Reza Sharifi]

Hi,

Can you provide relevant configs (interface and OSPF) from both routers?

[terrencepayet]

Hi Reza,

Thanks for your propmt reply.

Please see attached.

Thanks.

[glen.grant]

  What interfaces are you using to tie the routers together , I don't see a common subnet between them .

[terrencepayet]

Hi glen,

Thanks for the reply.

Am using fa0/1 on both routers and am using 172.16.11.253/30 on Site D and 172.16.11.254/30 on neighbouring router.

Thanks.

[Jon Marshall]

Can you shutdown one of the fa0/1 interfaces. Then on both routers enter "debug ip ospf events", bring the interface back up and posts results.

Jon

[terrencepayet]

Hi Jon,

Thanks.

Please find attached log. Note that this was taken from the neighbouring router not on site D as i would loose connectivity with site if i shut down fa0/1.

Take note that on neighbouring router OSPF you're seeing is from neighbouring routers coming from int fa0/0.

But the problem is with the f0/1.

thanks.

[Jon Marshall]

There are no hellos being transmitted on fa0/1. So can you do the same thing again and run the debug on the other router at the other end. Note you can still shut the interface down on the same router.

As for the link, it is a crossover cable connection between the routers or are there switches in the way.

Is the config you posted the full OSPF config ?

What IOS version are you running ?

Jon

[terrencepayet]

Hi Jon,

Thanks.

They are two different sites, running on a 512k ADSL cloud provided by ISP. From the ADSL modem it goes on fa0/1 for both sites.

For now i have added static routes. but there's too many routes to add.

And yes this the full ospf config.

We are using ios 12.2(24)

Could it be a convergence issue?

Thanks,

[glen.grant]

  A lot of the routers are passive interface default by default , make sure you have no passive interface under ospf   for both links on the routers .  Don't know about the cdp issue , if cdp is enabled on those interfaces and you can ping across cdp should work unless  the isp is blocking it somehow .

[terrencepayet]

Hi glen,

None of these interface has been set to passive as shown in the logs.

Do you think there's a bug?

Thanks.

[manish arora]

As already asked by Jon , what's the physical layer + data link layer between these affected routers ?

Manish

[terrencepayet]

Hi,

There's only an ADSL modem on each of those routers int fa0/1, and nothing more.

Thanks

[manish arora]

Can you try changing the network type to Point to Point and using static neighbor command and see if hello are than unicast to the neighbour rather than multicast.

Manish

[Peter Paluch]

Manish,

The network type would need to be point-to-point nonbroadcast in order to use the neighbor statement. A plain point-to-point uses multicasted OSPF packets and does not support the use of neighbor commands.

Best regards,

Peter