Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

Clocking Problem on WAN

I have a T1 Point to Point between my main office and remote office. We have been having sporadic connectivity issues and had our provider check into it. They said they are seeing a lot of frame slips on the line and that we needed to setup our routers such that one was providing clocking to the other because they were not providing us clocking. This point to point connection runs through 3 providers, Sprint, Bell and Verizon.

We have a 7200 on one side and a 3745 on the other. I am not sure how to tell the 7200 to provide clocking to the 3745 and how to tell the 3745 to receive clocking from the 7200. The 7200 also has several other point to point and frame relay interfaces that are receiving clocking from the line.

How can I configure the 7200 to provide clocking only on the P2P to the 3745 and how can I tell the 3745 to receive this clocking.



Re: Clocking Problem on WAN

Sorry for the brief answer but I have little time.

On side where clocking is required, set up something like:

It should not be required to instruct the 3745 to receive clocking from the line as this is the default setting.



New Member

Re: Clocking Problem on WAN

Hi, you need to program your external DSU to do this if you have one, or you can use the IOS cli for this. I believe serial interfaces default to line so you would need something like this on the 3745.

int s0/0

service-module t1 clock source internal

Then you can do a 'sh service-module s0/0' to see the details.

Same goes for the 7200. There should be similiar syntax there depending on the PA used. If you are terminating on a DS3, the T3 controller defaults to line also, so the best place for this is the remote router and set it to internal.