[cisco-voip] PRI Clocking

[Mike King]

Just for someone to check my sanity.
I'm having the standard argument with Telco today  (We don't see
anything, it must be your equipment)

I have a PRI that I've had complaints of dropped calls.

I go an check the log on the 2921 router, and see this  (Across 3
different dates, just one posted for brevity)

092856: Jul 30 2010 09:49:36.861 EDT: %MARS_NETCLK-3-HOLDOVER:
Entering Holdover for Controller T1 0/0/0
092857: Jul 30 2010 09:49:38.613 EDT: %LINK-3-UPDOWN: Interface
Serial0/0/0:23, changed state to down
092858: Jul 30 2010 09:49:47.113 EDT: %MARS_NETCLK-3-HOLDOVER_TRANS:
Holdover timer exceeded for Controller T1 0/0/0
092859: Jul 30 2010 09:49:47.113 EDT: %MARS_NETCLK-3-CLK_TRANS:
Network clock source transitioned from priority 1 to priority 10
092861: Jul 30 2010 09:57:23.612 EDT: %LINK-3-UPDOWN: Interface
Serial0/0/0:23, changed state to up
092863: Jul 30 2010 09:57:32.112 EDT: %MARS_NETCLK-3-CLK_TRANS:
Network clock source transitioned from priority 10 to priority 1

I also have CRC's on the serial0/0/0:23  (not a whole lot, just some)

Telco of course says they've pulled PM's and see nothing. I've been
pushing the issue with my Telco Rep, and he's suggested that since it
seems to be a clocking issue (His words) that maybe we should set our
PRI to internal clocking.

I reset the counters on my serial interface, and in the past 2 days,
I've recieved 1 CRC.  I've also not had the PRI drop any calls. (Or
the whole PRI drop, which is what I assume from those log messages)


I have another circuit at a different site, I reset it's counters at
the same time 48 hours ago, and It had this today (also I don't have
any reports of dropped calls, just problems faxing)..
12 runts, 0 giants, 0 throttles
32 input errors, 32 CRC, 0 frame, 0 overrun, 0 ignored, 2 abort

My question is this:

Is it Normal to have some number of CRC's on a PRI?
My personal experience is to ALWAY clock off Telco, and you should not
have any errors on my lines.  Am I wrong with this assumption?

Mike