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New Member

T1 Controller question

When I do a "sh controller T1" I get an entry:

Current port master clock: recovered from controller 3/1

What does this mean?

Cisco Employee

Re: T1 Controller question

we need to see the whole output of "sh controller T1 3/1" and other controller as well. All router need is a good stable clock source from one of the T1 line and looks like router had selected clock from other T1 line because of possible clock issue with T1 in 3/1controller.

New Member

Re: T1 Controller question

Yes indeed I am having problems with T1s. I have put in several tickets with AT&T with no resolution. this is a point to point T1 with the other end point set to "clock internal" and this end to line. The far end also has no errors and when AT&T loops me up, the errors go away:

Val.3662#sh controllers t1 3/1 brief

T1 3/1 is up.

Applique type is Channelized T1

Cablelength is short 133

Description: T1 to Las Vegas

No alarms detected.

alarm-trigger is not set

Version info Firmware: 20000922, FPGA: 15

Framing is ESF, FDL is ansi & att, Line Code is B8ZS, Clock Source is Line Primary.

Current port master clock: recovered from controller 3/1

Data in current interval (156 seconds elapsed):

3187 Line Code Violations, 6368 Path Code Violations

145 Slip Secs, 0 Fr Loss Secs, 141 Line Err Secs, 2 Degraded Mins

116 Errored Secs, 115 Bursty Err Secs, 29 Severely Err Secs, 0 Unavail Secs

Cisco Employee

Re: T1 Controller question

You can see that the clock source for T1 line in controller 3/1 is from Line as "Clock Source is Line Primary" and "Current port master clock: recovered from controller 3/1" points that its is the current line of clock source.

Now looking on all those stats, it looks to me that the line is having some serious clocking issue as we have "145 Slip Secs". Also there are many violations. So here is the url which will help you to troubleshoot that

New Member

Re: T1 Controller question

I've read this and I'm still having issues. I tried something for the heck of it:

I made the remote site (2600 WIC-1DSU-T1) clock source line and then set the home site (3600 VWIC-2MFT-T1) to clock source internal. It would no come up with this setup. This is a point to point t1 with a different provider but this 4th t1 is having the same issues. Is there something aboutthese VWICs that I'm missing? It'll only come up with the 2600 being providing the clock and 3600 clock line but with errors only on the 3600 side.

New Member

Re: T1 Controller question


I opened a case with Cisco and there telling me there was some sort of design issue/limitation on these cards. The tech said I need to separate these two VWICs into two different NMs on the router. (which defeates the purposed of getting these cards for me). I will try and update this thread with the results in case anybody is curious.