Multilink Issue

Unanswered Question

I have a 2851 at one site of our 4 site MPLS. At this site I have two T1's from our provider that I have configured as a Multilink. On Sunday one of the circuit had an issue. I was informed by our provider that the LEC had resolved this issue.

Now one of the Serial interfaces shows up/up while the one that had the circuit issue is showing up/down. Also when doing a sh int on the serial interface that is showing up/down it does not state "Link is a member of Multilink bundle Multilink1."

Could this still be an issue with the circuit? Or is it something else?

Here are the relevant part of the config:

interface Serial0/0/0:1

description T1 link to Sprint GMPLS

no ip address

encapsulation ppp

ppp multilink

ppp multilink group 1

interface Serial0/0/1:1

description T1 link to Sprint GMPLS

no ip address

encapsulation ppp

ppp multilink

ppp multilink group 1

interface Multilink1

description Link to GMPLS

bandwidth 3072

ip address

delay 2000

no cdp enable

ppp multilink

ppp multilink group 1

ppp multilink fragment disable


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Richard Burts Wed, 04/18/2007 - 03:17
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I do not see any issue in the config that you posted. If the serial interface is showing up/down I would believe that there is still an issue with the circuit. If the provider believes that they have fixed the problem you might try a shut and no shut on the serial interface to see if it reinitializes anything. But if it continues to be up/down I would go back to the provider and ask them to check again.



spremkumar Wed, 04/18/2007 - 03:20
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Its better to check up the loop physically on your link to make sure that your T1 is clean and up.

Once you are done with that you can put them back in bundle..

Is there any constraint at your end in running them as individual links rather bundling them onto a single logical link.

By bundling them you may not have the monitoring capability which you have when they are configured/used as individual links..

Because if one of the link goes down on the bundle you wont be able to identify or sense since the multilink link will be up and forwarding the traffic.


spremkumar Wed, 04/18/2007 - 20:28
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Hi Jim

We have had enough problems with the multilink bundle as you are facing now and at the end we decided to unbundle and subscribed to a single pipe.

You can run them as individual links and make sure you have your routing done to take care of traffic forwarding via both the links ..



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