Clocking issues PRI + Data t1s on a VWIC2-2MFT-T1/E1

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Apr 12th, 2008
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I have a Cisco 2821 that is getting two different T1 clocks from different providers. The Cisco 2821 has a VWIC2-2MFT-T1/E1 wic card. 1 t1 on the card is data, 1 is a voice PRI.

I am trying to figure out this proper configuration for this, I was thinking that this configuration would be correct:

network-clock-participate wic 1

network-clock-select 1 T1 0/0/1


controller T1 0/0/0

framing esf

clock source line independent

linecode b8zs

channel-group 0 timeslots 1-24

description MPLS Circuit


controller T1 0/0/1

framing esf

linecode b8zs

pri-group timeslots 1-24 service mgcp

description Voice PRI Circuit


IT is my understanding that you need to have network-clock-participate ON when using a voice gateway. The problem with the above config is this:

(config-controller)# clock source line independent

%Please remove network-clock-participate wic 0 first

How should this be configured?

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paolo bevilacqua Sat, 04/12/2008 - 05:36
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Hi, in most countries, properly set networks are synchronous to the same master source, so is not said you necessarily need independent clocking. So check first if you're getting slips with normal clocking.

Then in your example the wic in network-clock-participate should be 0, not 1.

Finally if you want to try independent clocking, follow router advice and remove the wic-pariticpate first.

Christopher Dozier Sat, 04/12/2008 - 06:23
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I have also run into this issue when trying it without network-clock-participate

# pri-group timeslots 1-24 service mgcp

%Please configure network-clock-participate wic 0 first

Perhaps, having network-clock-participate and both set to clock source line, no t1s set to independent is the key? I can not test this at the moment


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