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Community Member

Slip Secs on the Link


Is there any practical issues faced while terminating internation link and a domestic link on a same router.

A - B - C ; A- B is a internatioal ckt and B-C is a domestic Circuit.

On the E1's of B, lot of slip secs are faced on the international ckt. Ckt has been checked with BER and it seems to be fine. Same international ckt when connected separately on a sepate router D it doesnt report any slip secs/errors.

B - 3600 Router "flash:c3640-is-mz.122-12a.bin".

Tried the troubleshooting tips of E1 link which has not resulted any change.

Thiis is causing severe degradation on the link.

Any suggestions ...


R.Sundara Rajan


Re: Slip Secs on the Link


there seems to be a clock synchronization issue. Frame slip errors indicate usually, that there are clocking issues (the real PLL clock in the E1 controller has to match the provider equipment).

I am assuming both links are from different providers? In this case their networks will not be synced against each other. This might cause the problems for your 3640. What are the clock source settings? I mean "clock source line" or something similar on each of the E1 controllers.

I would first opt for "clock source line" for both E1 and if that is causing the problems go for internal clocking. You might not be able to overcome the issue without second router, though, but it is worth a try.

Hope this helps! Please rate all posts.

Regards, Martin

Community Member

Re: Slip Secs on the Link

Hi Martin,

Tried using clock source line for international ckt and after that slip secs increases in double the counters. So we have to force the same by internal.

International and Domestic ckts are from different service providers

International ckt are terminated on s2/2& s2/3 of 3640 router which is having VWIC-2MFT Card.clock Source defined as Internal

Domestic ckt is terminated on s2/0 & s2/1 clock configured as line.

Last option for us which is left out is to terminate the international and domestic ckts separately on two separate rotuers and connect them back 2 back by FE



R.Sundara Rajan


Re: Slip Secs on the Link


Can you try the 'clock source line independent' command ? It will allow the use of 2 independent clock sources on each line of the VWIC-2MFT instead of using one to clock the other ?

Hope that helps - pls rate the post if it does.


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