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Webcast-Catalyst9k
New Member

T1 line troubleshooting.

I have a problem with a T1 line. Here is a ping to the far router.

Reply from 10.48.29.2: bytes=32 time=2059ms TTL=254

Reply from 10.48.29.2: bytes=32 time=4ms TTL=254

Reply from 10.48.29.2: bytes=32 time=249ms TTL=254

Reply from 10.48.29.2: bytes=32 time=701ms TTL=254

Here is the show int serial0 on the far router:

Serial0 is up, line protocol is up

Hardware is PowerQUICC Serial

Description: Connected to GCITDR01 CKT#DHDG509029

Internet address is 10.48.29.2/30

MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation HDLC, loopback not set

Keepalive set (10 sec)

Last input 00:00:00, output 00:00:00, output hang never

Last clearing of "show interface" counters never

Queueing strategy: fifo

Output queue 0/40, 3827 drops; input queue 0/75, 0 drops

5 minute input rate 0 bits/sec, 2 packets/sec

5 minute output rate 0 bits/sec, 0 packets/sec

195467997 packets input, 1475903131 bytes, 0 no buffer

Received 2184243 broadcasts, 5 runts, 10 giants, 0 throttles

60589 input errors, 24505 CRC, 16830 frame, 0 overrun, 0 ignored, 19254 abo

rt

171951524 packets output, 2015792355 bytes, 0 underruns

0 output errors, 0 collisions, 144 interface resets

0 output buffer failures, 0 output buffers swapped out

50 carrier transitions

DCD=up DSR=up DTR=up RTS=up CTS=up

Is there anyway that I can troubleshoot the serial card?

3 REPLIES
Silver

Re: T1 line troubleshooting.

The first thing you need to do is reset all the counters on the router to determine how bad your errors are. You are receiving (or have received) input errors on the serial 0 interface. Try doing a SHOW CONTROLLERS SERIAL 0 command to look at the layer 1 statistics of the T-1. It will show you the alarms and errors on the T-1 itself. Also re-verify that you have all your DS0's configured correctly. Make sure that if you are supposed to be using a full T-1 bandwidth then you should have 24 DS)'s configured. Make sure that your Coding and Fraing for the T-1 are also configured correctly. Try performing a T-1 loopback onto yourself to verify if the errors are coming from within your building or from the carrier. Verify that the remote end is receiving errors or not. Once you have determined most of this information then you can start to pinpoint your point of failure...Good Luck...Pls rate...

Re: T1 line troubleshooting.

CRC errors appearing in the output. Get the link tested by ISP.

New Member

Re: T1 line troubleshooting.

I reset the counters as mentioned above.. A little history on this T-1 line though is needed. At one point in time we had issues and bell south came out and checked it out. I believe the issues are gone now and were reflected in the counters since they have most likely never been reset. Reset the counters now i have the below..

Serial0 is up, line protocol is up

Hardware is PowerQUICC Serial

Description: Connected to GCITDR01 CKT#DHDG509029

Internet address is 10.48.29.2/30

MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation HDLC, loopback not set

Keepalive set (10 sec)

Last input 00:00:00, output 00:00:00, output hang never

Last clearing of "show interface" counters 01:29:35

Queueing strategy: fifo

Output queue 0/40, 0 drops; input queue 0/75, 0 drops

5 minute input rate 1000 bits/sec, 3 packets/sec

5 minute output rate 1000 bits/sec, 3 packets/sec

32552 packets input, 6207500 bytes, 0 no buffer

Received 878 broadcasts, 0 runts, 0 giants, 0 throttles

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort

33748 packets output, 3840415 bytes, 0 underruns

0 output errors, 0 collisions, 0 interface resets

0 output buffer failures, 0 output buffers swapped out

0 carrier transitions

DCD=up DSR=up DTR=up RTS=up CTS=up

I am going to try another serial intferace.. I believe we have a bad one that keeps getting moved around instead of being replaced.

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