TDP and IP Reachability

Unanswered Question
Dec 10th, 2007

Hi all,

We ve got a downstream location terminating on Multilink in 7600 with MPLS enabled. When one of the serial bundled in Multilink flapped, TDP was flapping and the IP reachability for the other end of the multilink was not there. After we did a shut and no shut everything started working fine.. My question is even if TDP/LDP goes down on directly conn interfaces, IP reachability should be there? Or is there anything else? Kindly clarify....

Thanks in advance...

I have this problem too.
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swaroop.potdar Mon, 12/10/2007 - 07:46


TDP/LDP does not interfere with control of IP reachability.

On the contrary TDP/LDP would work only if you have ip reachability between 2 devices.

The problem you have described here regarding losing ip reachability when a member link of the bundle bounced seems more like a bug. Since you lost ip reachability your TDP/LDP flapped.

You can consider using LDP session protection if you have an alternate path between any 2 devices to avoid session flap when you lose the directly connected interface for a flap.

here is a reference for the feature.



arun kumar Mon, 12/10/2007 - 21:25

Hi Swaroop,

Thanks for your informative reply... But unfortunately we dont have an alternate path to reach the other end of the link...

We are facing quite lot of issues in Multilink configured on 7600... Probably we need to search for the BUG...

Thank you...

gauravprakash Fri, 12/14/2007 - 07:58

There are issues with 7609 with some IOS , where Multilink + QOS is not working .. check if its the same..


Gaurav Prakash


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