Clock slips on VWIC-2MFT in 2811

[mpervere]

Hi All -

I have a 2811 that I'm in the process of turning-up to support a 4xT1 using VWIC-2MFT-T1's. The question is how to "correctly" set clocking on the MFT's.

As is typical of the 2MFT's, as soon as a 2nd T-1 on a VWIC-2MFT comes up, I start taking "Slip Sec"s on the 2nd T-1. I have tried different clock source combinations, including "clock source line primary", various "network-clock-participate" (or not) combinations, and about a dozen other stab-in-the-dark configurations. Before I started playing with it, the slips were consistently every 9 seconds. After playing with it, I got them to every 18 seconds. But there shouldn't be ANY. So the question is what SHOULD the correct timing configuration be on that platform?

The VWIC-2MFT-T1's are in slots 1 and 3, so the controllers involved are 0/1/0, 0/1/1, 0/3/0 and 0/3/1. Ideas?

Thanks!

Mike

[scottmac]

I believe you want one of the interfaces set to "Line" and the other to "Loop."

For multi-interface T1/E1 WICs, deriving clock from more than one interface will cause the slips.

Good Luck

Scott

[jaywydra]

Don't listen to that guy ScottMac. :)

[webnetwiz]

You're right, there should be NO slips whatsoever. I've experienced a similar problem on the 2600s with the VWIC-2MFT-T1. My problem was that when one of the Ts would go down, the other would lose clock, which meant that it obtained clock from the 1st T1, while it's supposed to clock from the network. Opened a TAC case and it turned out to be a bug in the IOS for that particular WIC model. I fear that you may be looking at the same type of situation. Cisco had me test all the lines, down to a point where a BERT tester passed the circuits with flying colors.

[pkhatri]

Hi Mike,

If you require only a single channel-group on each T1, then you can use the independent clocking domain (NMSI mode) so that the two T1s can derive their clocking independently. You cannot use this if you require more than one channel-group on each T1.

Pls try the following (I've only included the clock configuration - use the correct linecode and framing as per your needs). You will, of course, need to configure the T1s at both ends, so I've included configs for both ends...

On Router 1

===========

controller T1 0/1/0

clock source line independent

!

controller T1 0/1/1

clock source line independent

!

On Router 2

===========

controller T1 0/1/0

clock source internal independent

!

controller T1 0/1/1

clock source internal independent

!

Do the same for your other two T1s....

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

Regards,

Paresh.

[aebba]

Paresh,

Will this configuration work if I am bundling the T1s with MultilinkPPP.

Thanks,

Armand.

[camdoggle]

We're working on the same thing, reviving an ollld thread Any ideas if plhatri's configuration is viable for multilink PPP? We have the same configuration, dual point-to-point T1's connecting from Site A to Site B over multilink. We're having some errored secs on the first T1 controller:

Version info Firmware: 20100222, FPGA: 13, spm_count = 0

  Framing is ESF, Line Code is B8ZS, Clock Source is Line Independent.

  Data in current interval (1 seconds elapsed):

     0 Line Code Violations, 0 Path Code Violations

     0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins

     0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs

  Total Data (last 1 15 minute intervals):

     0 Line Code Violations, 2 Path Code Violations,

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

     2 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs

Thank you,

Cam

[paolo bevilacqua]

Your circuit appears to be fine. If you receving too many errors, complain to telco, ask long duration BER test.

[camdoggle]

Thanks for the reply.. Here is the recent show controller t1:

  CRC Threshold is 320. Reported from firmware  is 320.

  Data in current interval (801 seconds elapsed):

     0 Line Code Violations, 3 Path Code Violations

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

     3 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 5 Unavail Secs

  Total Data (last 9 15 minute intervals):

     0 Line Code Violations, 55 Path Code Violations,

     0 Slip Secs, 1 Fr Loss Secs, 0 Line Err Secs, 33 Degraded Mins,

     42 Errored Secs, 0 Bursty Err Secs, 1 Severely Err Secs, 133 Unavail Secs

So a little over 2 hours and 42 error secs.. Are you saying that would not impact performance or voip/data throughput between sites? Thanks for the info, I will relay that to Telco to see what they can do.

[paolo bevilacqua]

A better way to look the true impact of this is "show interface", and "show log" to see it the circuit has bounced.