Route Advertisement Problem

[netlife]

Hi All,

I am having cisco 3662 router.I have added new segment in a fa0/1.A switch is connected to Fa0/1 via port 2/1.
After configuration on this change from the switch(on new segment) i could ping the far end serial.
Once i had shutdown the switch for an ativity w/o shutting down fa0/1 administratively.After switching on the switch again i had seen i cannot ping far end serial.
Tried traceroute,packets are reaching upto the gateway but not beyond it.
Seen configration on router network statement for this new segment in BGP process is still there...
Trying to resolve this issue. Pls help.

Thanx,

Cheers,
Netlife.

 

[fmonteiro]

From the router, could you ping the switch, or any host in this segment?

From the router, could you ping the "far end serial"?

Does a router located in the "far end serial" know the new segment added (I would check for a network itself or by a consistent default gateway) ?

 

[netlife]

Hi,

Thanx for replying.Here are the tests done so far...

From the router i can ping the switch connected to its fast ethernet port.
From Switch i can ping the gateway but not the far end serial.
From far end router i cannot ping my routers fast ethernet port (Fa0/1)which is connected to the switch.
I have tried tracing this new segment from one of the router in the far end backbone but it is revolving aroung that data network mean cannot reach even the far end router
for this new seghment.

Pls let me know any other way to locate this problem.

Cheers,

netlife

 

[netlife]

Hi fmonteiro,

We have found that in the far end data network 4 BGP
speaking routers are advertising this network in wrong direction causing routing loop.
But is it affecting in ping the far end serial port of a router which is directly connected to my router.....
I think even if there is routing loops occured in the far end backbone there should be no problem in pinging the far end serial from my router since that far end router is a just a next hop to me.
Pls help....

Cheers,
netlife.

 

[fmonteiro]

From the far end router do a trace do the Fa0/1 address and try to figure out the used path. It should not be using the obviously path. You may also use a &quot;sh ip route <Fa0/1 network>&quot; and note the next hop for this route. Check if do you have a gateway of last resort defined. This is the path that will be used is the route is not known.
Do you mean that from that you cannot ping the far end router from the 3662? Do a trace also from this router.
Let us know anything else you my find.

 

[netlife]

I have tried the trace route from the far end but found that it is moving among the backbone routers.From my router's serial 1/0 i can ping the far end serial 0/1/1.
But from the Fa0/1 cannot ping far end serial.
Let me confirm one thing that if at all there is a routing loop occured in the far end backbone,am i able to ping far end serial?

netlife.

 

[fmonteiro]

Could this new added segment be using a network address already used somewhere in your network? In the far end router do a &quot;sh ip route <new net add>&quot;. The route should be reached via your serial 1/0. Anything else may be wrong, and it could be a loop.