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New Member

Alarms on two different routers on the same T1

I'm trying to set up a point-to-point T1 and I get the same alarm on both ends of the T1. What am I doing wrong? Two different routers. . I do have the VWIC set with a channel group of timeslots 1-24 and a speed of 64k. The LEC says they can loop up to all their equipment but they can't see mine. When they try to loop me up I can see them clearing the alarm on my end but they don't get anything back. Any help would really be appreciated

This is from my 3662 with the VWIC:

1 3/0 is down.

Applique type is Channelized T1

Cablelength is short 133

Receiver has remote alarm.

alarm-trigger is not set

Version info Firmware: 20000922, FPGA: 15

Framing is ESF, Line Code is B8ZS, Clock Source is Line.

Current port master clock: local osc on this network module

On my 2611 with the WIC:

Module type is T1/fractional

Hardware revision is 0.96, Software revision is 0.2,

Image checksum is 0xED22BEC5, Protocol revision is 0.1

Transmitter is sending remote alarm.

Receiver has loss of frame, AIS alarm,

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 01:34:55

loss of signal : 0,

loss of frame : 1, current duration 01:34:41

AIS alarm : 1, current duration 01:34:41

Remote alarm : 0,

Module access errors : 0,

Total Data (last 6 15 minute intervals):

0 Line Code Violations, 0 Path Code Violations

1 Slip Secs, 5400 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins

0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 5400 Unavail Secs

Data in current interval (283 seconds elapsed):

0 Line Code Violations, 0 Path Code Violations

0 Slip Secs, 283 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins

0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 283 Unavail Secs

3 REPLIES
New Member

Re: Alarms on two different routers on the same T1

Looking at the information provided, I see that the 3662 is receiving an alarm and the 2611 is sending an alarm. The 2611 says that it has lost framing and is receiving AIS. This would indicate to me that the 2611 is OK. Look at the 3662 end of the circiut.

Remember that a T1 is a full duplex circuit. Your receive can be good while your transmit is bad. My guess is that your transmit is bad. There are two reasons that I say that. The 2611 is receiving AIS (the LEC has nothing to send it). Also, you say that you see the alarm clear when the LEC tries to loop up your equipment.

Try this: Get a looping plug (pin 1 looped to pin 4 and pin 2 looped to pin 5) and plug it in to the 3662. This should bring your 3662 up. If it does, go to the DEMARC and loop back the line toward the 3662. Again, this should bring the 3662 up. To be sure that the problem is the LEC, perform the same tests at the 2611. If all of these tests bring up your equipment, work with the LEC to solve the trouble. If any of these tests fail, you have a problem at the end local to the test.

If you do have a local problem, you can loop back toward the remote. This should bring up the remote, further proving your diagnosis. There is a situation where this won't work. If the loss is greater than about 10-12 db, a hardwire loop will be too long on the return path.

Once you have isolate the problem it should be easy to fix.

New Member

Re: Alarms on two different routers on the same T1

Yup, that was it. Made a loop back plug and basically determined that one port on the 3662 was bad. Maybe I was too ready to blame the telco because of the past experiences. Thanks!

New Member

Re: Alarms on two different routers on the same T1

Glad you found the problem. By the way; I worked for a telco for 30 years. You are not the only one to blame the telco first - it happens all the time.

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