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gavin han

multilink issue


I've multilink configured which consiste of two T1s+new T1( = three T1s). this new T1 has been causing issue. site was working normal but since new T1 was taking errors we submitted this ckt to telco for testing. site literally got an outage after telco tested this faulty T1. i removed this faulty T1 from the multilink and site is good now. so there looks like an issue with the faulty T1.

now, telco is telling that errors are coming from our network. I don't think this is correct.

Please advice what would be the exact issue.


Mahesh Gohil
Rising star

Hi Gavin,

When telco is telling error is coming from you side...can you focus on how he is performing the test..

1- Does he perform test when your link attached to router.

2- can you ask him to test end to end like using any berr meter to test the link.

3- is there any spare T1 port in your router to test if that T1 port is faullty or not.

4- can you try some test (ping test) by giving loop from other end to test the link. please make sure you do not bundle

it in multilink when doing test.

there are many possibility so it is better you go step by step.

hope this is helpful



Tharak Abraham

Is the Telco able to loop till the Demarc/Smartjack ?

If thats fine, then they should be trying till the CSU/DSU with a softloop or a hardloop...

These results will show whether its a faulty WIC card.

You may also use some extended ping:-

0x0000 will identify line code mismatches (e.g. AMI vs. B8ZS), all binary 0's

0xFFFF will identify repeater power problems, all binary 1's

0x4040 will identify timing problems, every 8th bit would be a 1.

Once we've seen such a thing when we hit a bug with the MLP configuration when all the tests where fine with the member links and we had to reconfigure the MLP to solve the issue ..-:) but very rare..yea.