[cisco-voip] Slip Errors on our Routers

[Bob]

Date: Fri, 3 Oct 2008 10:22:15 -0500
From: "Jeff Ruttman" <ruttmanj at carewisc.org>
Subject: [cisco-voip] Slip Errors on our Routers
To: <cisco-voip at puck.nether.net>
Message-ID:
	<CA2E1F4500047148BF60D73597EFA05F0806C7 at ma1-exc01.ec2802.elderc.org>
Content-Type: text/plain; charset="us-ascii"

Greetings, 
We're getting some QoS complaints and lots of trouble faxing via an ATA.

I'm definitely not a router guy, but I'm trying to do some research.

It's my understanding that too many slip errors cause static and choppiness.
And maybe even echo?

I don't know how many slip errors are "too many," but I'm thinking we've
surpassed that threshold.

Any comments?


Slips and sampled analog data (modems, faxes) don't mix. Pretty much any
slips are too many. Hits happen, but you shouldn't normally have any slips.
>From the info you sent previously, you are having a frame slip every 10
seconds on average. Not good. Here's the config you want to do - fix the
interfaces to match yours if necessary. Also, I'm showing what you are
hoping for when you do a "show controller t1" from one on mine. 

Also, where does port "0" on the pri card go? Is it also voice, and does it
go someplace that is traceable back to the public network? Is it a pure data
T1 - like frame relay? Certain T1 interface cards only have one PLL, so the
clock source for both T1's has to be in sync. If so, you'll want to clock
the voice T1 from the remote as shown below, as the Frame Relay T1 will
tolerate some slips. 



network-clock-participate wic 3 
network-clock-select 1 T1 0/3/1

and 

network-clock-select 2 T1 0/3/0  - if that's also a voice T1

Mine happens to be 0/0/0, and 0/0/1, and it's been in service for months.

SanDTELRTR#sho controllers t1
T1 0/0/0 is up.
  Applique type is Channelized T1
  Cablelength is long gain36 0db
  No alarms detected.
  alarm-trigger is not set
  Version info Firmware: 20050620, FPGA: 16, spm_count = 0
  Framing is ESF, Line Code is B8ZS, Clock Source is Line.
  CRC Threshold is 320. Reported from firmware  is 320.
  Data in current interval (263 seconds elapsed):
     0 Line Code Violations, 0 Path Code Violations
     0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins
     0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs
  Total Data (last 24 hours)
     0 Line Code Violations, 0 Path Code Violations,
     0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins,
     0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs
  T1 0/0/1 is up.
  Applique type is Channelized T1
  Cablelength is long gain36 0db
  No alarms detected.
  alarm-trigger is not set
  Version info Firmware: 20050620, FPGA: 16, spm_count = 0
  Framing is ESF, Line Code is B8ZS, Clock Source is Line.
  CRC Threshold is 320. Reported from firmware  is 320.
  Data in current interval (266 seconds elapsed):
     0 Line Code Violations, 0 Path Code Violations
     0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins
     0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs
  Total Data (last 24 hours)
     0 Line Code Violations, 0 Path Code Violations,
     0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins,
     0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs