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Bronze

T-1 clock source

Hi,

I'm going to be replacing a few 1760's with new 1921's. There's a main site and two branches. The original configs puzzle me because I assume both T-1's at the main site are the same provider, but one is clock sourced internal and the other isn't.

Main site Wan

interface Serial0/0

description ****Link to P Branch****

ip address 192.168.150.1 255.255.255.252

ip nbar protocol-discovery

ip route-cache flow

service-module t1 timeslots 1-24

service-policy output voice

!

interface Serial0/1

description ****Link to A Branch****

ip address 192.168.150.5 255.255.255.252

ip nbar protocol-discovery

ip route-cache flow

service-module t1 clock source internal

service-module t1 timeslots 1-24

service-policy output voice

On the branch sites I have this

P-Branch

interface Serial0/0

description ****Link to Main Site****

ip address 192.168.150.2 255.255.255.252

ip nbar protocol-discovery

service-module t1 timeslots 1-24

service-policy output voice

A-Branch

interface Serial0/0

description ****Link to Main Site****

ip address 192.168.150.6 255.255.255.252

service-module t1 timeslots 1-24

service-policy output voice

Why would the main site T-1's be clocked differently. How should this be setup. I thought most T-1 setups derived clock from the line not internal.

Everyone's tags (3)
1 ACCEPTED SOLUTION

Accepted Solutions
Hall of Fame Super Gold

T-1 clock source

That is because some circuit can be provisioned to transport clock trasparently, so if not error and slips, that is fine.

5 REPLIES
Hall of Fame Super Gold

T-1 clock source

That is because some circuit can be provisioned to transport clock trasparently, so if not error and slips, that is fine.

Bronze

T-1 clock source

Thanks.

But it cannot be internal on both ends, right?

I got the 1921's from another engineer and I believe he was doing loopback testing so the new configs have internal clock on both the main site and the branch sites.

Hall of Fame Super Gold

T-1 clock source

Correct, cannot be internal on both sides.

Thank you for the nice rating and good luck!

Bronze

T-1 clock source

Depending on the circuit, which of these combinations on matched ends are correct?

clock not specified, clock not specified

internal, clock not specified

internal, line

line, clock not specified

Hall of Fame Super Gold

Re: T-1 clock source

There is no such setting as "clock not specified", when nothing is specified the default of "clock source line" is applied.

The two valid combinations are both sides line, or one side internal and the other line.

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