T1 Troubles

[funkbass81]

we have a t1 connected to a cisco 2620 router. ive been having trouble with the connection cutting out. a show service-module shows loss of frame, AIS alarm, and remote alarms. any ideas?


sh service-module
Module type is T1/fractional
Hardware revision is 0.96, Software revision is 0.2,
Image checksum is 0x73D70058, 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 18:27:09
loss of signal : 0,
loss of frame : 81, last occurred 00:02:59
AIS alarm : 72, last occurred 00:02:59
Remote alarm : 60, last occurred 00:13:30
Module access errors : 0,
Total Data (last 73 15 minute intervals):
0 Line Code Violations, 10217 Path Code Violations
6 Slip Secs, 2154 Fr Loss Secs, 0 Line Err Secs, 207 Degraded Mins
1427 Errored Secs, 1129 Bursty Err Secs, 1001 Severely Err Secs, 1366 Unavail Secs
Data in current interval (642 seconds elapsed):
0 Line Code Violations, 255 Path Code Violations
2 Slip Secs, 104 Fr Loss Secs, 0 Line Err Secs, 6 Degraded Mins
54 Errored Secs, 41 Bursty Err Secs, 69 Severely Err Secs, 36 Unavail Secs

 

[spidey07]

Call it in to the provider. Have them perform intrusive tests (will take ckt down) and go as far as looping your CSU/DSU.

Make sure the cable from the smart jack to the CSU/DSU is good.

 

[funkbass81]

called it in, theyre gonna run the tests after hours

 

[spidey07]

heh, I'd imagine you are having all kinds of trouble with it. Looks like a pretty dirty circuit. Loss of frame is pretty bad.

 

[cross6]

Is some loss of frame normal? I just checked on two of my T1 routers and I had a few (under 10). The last being about 3 weeks ago.

 

[spidey07]

A healthy T1 will have no errors at all.

Loss of Frame is bad. It basically means you don't have a clock and can't "frame" data. At this point you can move no data at all.

 

[cross6]

Originally posted by: spidey07
A healthy T1 will have no errors at all.

Loss of Frame is bad. It basically means you don't have a clock and can't "frame" data. At this point you can move no data at all.

Is that typically a line problem or a csu/dsu problem?

 

[spidey07]

Rarely if ever is it a CSU/DSU problem. There's not much to them. I think I've only seen one or two "bad" CSUs on the 1000s I've installed.

Most T1 problems are cabling/clocking or the card in the COs mux goes bad.

 

[cross6]

Originally posted by: spidey07
Rarely if ever is it a CSU/DSU problem. There's not much to them. I think I've only seen one or two "bad" CSUs on the 1000s I've installed.

Most T1 problems are cabling/clocking or the card in the COs mux goes bad.

Last clearing of alarm counters 2y30w
loss of signal : 8, last occurred 39w6d
loss of frame : 25, last occurred 4w6d
AIS alarm : 13, last occurred 4w6d
Remote alarm : 4, last occurred 10w0d
Module access errors : 0,


Looks like we had a prob or two about a month ago.

 

[funkbass81]

Originally posted by: spidey07
Rarely if ever is it a CSU/DSU problem. There's not much to them. I think I've only seen one or two "bad" CSUs on the 1000s I've installed.

Most T1 problems are cabling/clocking or the card in the COs mux goes bad.

we have a mux in the basement, it hasnt worked right since they put it in.

 

[cmetz]

Make sure to press your carrier HARD on getting an SLA credit for the time span they have failed to deliver a reliable T1 line. That tends to help them decide to really fix things.

Many T1 problems can be fixed... for a while... by the process of resetting the mux cards and running invasive loopback diagnostics. If they say "we tested it and it's fine now" be wary.