[c-nsp] full utilization on a T1 causing CRC/frame errors?

[Jared Mauch]

	This sounds like a load.

	Full T1 circuits will not show any such errors, otherwise
applications such as voice T1/PRI services which "fill" the entire circuit
would also be seeing such errors.  You should continue to work with them to
isolate the source of errors.  You will see things like output
drops and other errors accumulate on your interface, as well as possibly lack
of buffers, but not CRC, framing or 'arbort' types of errors.

	Ideally you'd start with your T1 PM's, such as
the output of "show controller" or "show service-module"

	You'll see outputs like:

2610#show service-module 
Module type is T1/fractional
    Hardware revision is 0.88, Software revision is 20050811-0.3,
    Image checksum is 0x80ACD1B3, Protocol revision is 0.1 
Receiver has no alarms.
Framing is ESF, Line Code is B8ZS, Current clock source is line, 
Fraction has 24 timeslots (64 Kbits/sec each), Net bandwidth is 1536 Kbits/sec.
Last module self-test (done at startup): Passed
Last clearing of alarm counters 4w0d
    loss of signal        :    0, 
    loss of frame         :    0, 
    AIS alarm             :    0, 
    Remote alarm          :    1, last occurred 4w0d
    Module access errors  :    0, 
Total Data (last 96 15 minute intervals):
    0 Line Code Violations, 1 Path Code Violations
    0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 1 Degraded Mins
    1 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs
Data in current interval (508 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


	The errored or degraded seconds/minutes should really not
increase at all.  Exceptions you may be willing to make is if
it's a very rural circuit and there are a very low level of errors.

	Otherwise, your circuit should be clean, including in adverse
weather conditions.  I recall one circuit that would go down
when it rained.  Eventually the pole it was on was hit by lightning and
the wiring caught on fire.  Once it was replaced the circuit worked 
perfectly.

	- jared

On Mon, Aug 28, 2006 at 02:15:07PM -0400, Burton Windle wrote:
> Maybe I'm just showing my inexperience, but I have an ILEC telling me 
> (verbally; they refused to put it in writing, suggesting that I google it 
> instead) that fulling utilizating a T1 frame relay circuit will cause CRC, 
> frame, and 'abort' input errors on my serial int's input counters.
> 
> Any truth to this?
> 
> 
> -- 
> Burton Windle                           bwindle at fint.org
> 
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-- 
Jared Mauch  | pgp key available via finger from jared at puck.nether.net
clue++;      | http://puck.nether.net/~jared/  My statements are only mine.