[c-nsp] Debugging T1 Bounces on CT3

[Bill Wichers]

> Maybe I am just stupid here, but the DS3 span and the DS1 spans are
> totally separate. I.E. It is possible to have an error on a DS1 that is
> NOT going to show up in any way on the DS3 span, nor should it. It will
> show up on that individual DS1 span's error reports, but not on the DS3.
>
> Am I missing something?

Nope, sounds right. Errors on individual T1s should show up in their
respective channel on the DS3 side, but shouldn't effect the DS3 itself --
the DS3 framer is supposed to keep the T1s in the right timeslots within
the DS3. I suppose if you had a bad framer wierd things might happen, but
I've never seen that.

> In any case, these are VERY CLEARLY LCVs at the DS3 level, more
> specifically, RX LCVs at the Cisco end. The Far End (MX-2800) shows no
> LCVs.

I think you have some defective/damaged equipment in your system. If
you've already replaced the cables then it's probably either one of the
BNC connectors on the units or something internal. I've seen corrosion
inside the BNC center pin cause problems, but a few plug/unplug cycles
will usually clear that. I've also seen the receive-side matching
transformers on the Cisco DS3 PA's get damaged electrically (not sure
exactly how), which has resulted in strange problems for me in the past
(usually causes similar problems to running a far too long DS3 cable run).
If you have a spare PA-MC-T3 and a spare mux, try trading them out one at
a time and see if the problem is in one of the devices. Normally DS3 links
aren't so picky about minimum lengths of cabling, IMHO.

     -Bill

*****************************
Waveform Technology
Systems Engineer