[cisco-voip] Question about T1 clocking

[Estes, Timothy]

I have this running on about 90 28XX routers in the field. Sprint MPLS circuits on the data side and Verizon or AT&T PRIs. You have to set network clock select to the PRI for it to come up, therefore the data circuit slips. Out of the 90 sites, only 2 have required new VWICs because of errors. The rest tolerate the slips. I see as low as 15 and as many as 90 slip seconds on the data circuits. 40 or 50 seems to be the limit for me, your mileage may vary.



Timothy Estes
Data Network Operations Engineer
ACS / Spherion
Ft. Lauderdale FL

From: cisco-voip-bounces at puck.nether.net [mailto:cisco-voip-bounces at puck.nether.net] On Behalf Of Ed Leatherman
Sent: Wednesday, February 04, 2009 9:38 AM
To: cisco-voip at puck.nether.net
Subject: [cisco-voip] Question about T1 clocking

Hi folks,

Been thru a number of threads and also "configuring digital voice ports" out on cisco.com<http://cisco.com>.. I think i understand what I need to know from it but for one question.

I've got a regional campus that wants to connect a long distance (sprint I think) T1 to an existing IOS gateway that has a VWIC2-2MFT-T1 with a free port. The other port is a PRI to their local service provider. i've told them that I believe this will cause clocking issues since they are from different carriers and would not recommend it.

My other thought was to add another VWIC to this router so that the long distance T1 has a seperate PLL, but then I started reading about the network-clock-select - even if I did this, the clocks running the DSP's would still be synched to one particular line clock and i'd still likely get slips, is this this true? Is my only option to get a seperate router for this application if I want to avoid having clocking problems?

Thanks in advance!

--
Ed Leatherman
Assistant Director, Voice Services
West Virginia University
Telecommunications and Network Operations
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://puck.nether.net/pipermail/cisco-voip/attachments/20090204/830da258/attachment.html>