At 03:55 PM 6/1/01 -0400, you wrote:
>Also sprach Jim Johnson
>>Recently, in preparation for a telco switchover, we have been testing a
>>new phone company and currently we have three PRIs up.
>
>>About a week ago, we start getting numerous reports of disconnect
>>problems, so I started looking at this problem and I am a bit
>>frustrated.
>
>>Of course, the phone company monitored the circuits and declared
>>everything fine on their end.
>
>>The only thing that I am seeing is a small number (0 to 100) of Code
>>Violation errors in each 15 minute interval when I look at the Near End
>>Current Intervals.
>
>>From looking at the stats, these errors initially were only showing up
>>on the third PRI, so we went and powered down the chassis and moved the
>>circuits around to make sure it wasn't the equipment.
>
>>However, today I am seeing these errors on all the PRI's.
>
>>What would cause these errors and what should I look at from here?
>
>Line Coding generally refers to AMI and/or B8ZS. You might have your
>equipment set up for B8ZS and some piece of equipment in the transport
>between you and their switch (or the switch itself) might be set for
>AMI...it only takes one piece of equipment being set wrong to cause
>these.
>
>The best way to test this is to run an all-0's pattern over a
>loopback'ed line.
>
>AMI and B8ZS are intended to maintain 1's density on a T1, so running
>all-0's over it will cause the coding mechanisms in AMI and B8ZS to be
>used very frequently. If a piece of equipment in the transmission path
>is set to AMI when it should be B8ZS, you'll see line coding errors rack
>up quickly.
>
>This all assumes, of course, that you have some piece of equipment
>capable of running Bit Error Rate Testing (BERT). The DSPs do have some
>limited capabilities in this area themselves, but they're not the
>easiest thing to work with.
>
>If you've got a cisco t1 card (with integrated csu/dsu), they can often
>do BERT...as can some stand-alone CSU/DSU's. Of course, if you have
>access to a T-berd, then you've got it made in the shade. :)
>
>I use a port on our PA-MC-8T1 to do BERT when I need it, FWIW.
>
>If this isn't your problem...well...I might be able to come up with
>other explanations, but not off the top of my head. :)
>--
>Jeff McAdams Email: jeffm(a)iglou.com
>Head Network Administrator Voice: (502) 966-3848
>IgLou Internet Services (800) 436-4456
>
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