Serial Interface goes down often

[csanchez]

I have two Serial T1 WAN interfaces on a Cisco 2610 Router that go out to two seperate WAN sites. The serial0/0 connection went down twice last night, all within an hour of each other. My network monitor indicated that there was high packet loss on the Remote Server and within a few seconds it reported the Serial0/0 interface as being down. This happen twice and has not happen since. How can I troubleshoot this issue? Also, the monitor reports that the router is experiencing alot of medium and big buffers missess. Any advise is appreciated. Thanks.

Carlos

[smif101]

do a clear counters on router, then wait 5 minutes and do a show interface serial 0/0 and post that. I would guess you are getting errors and then it flaked out. The best way to troubleshoot it is call the Telco and explain the problem, they may have had an outage last night. The other thing is to put a test set on the line and end to end and if you have problems start doing loop testing until you figure out where the problem is.

[csanchez]

Here is the output after about 9 minutes, but it looks like there isn't much of a problem. What exactly do you mean by putting a "test set on the line and ent to end".

Thanks again

Serial0/0 is up, line protocol is up

Hardware is PQUICC with Fractional T1 CSU/DSU

Description: CID# 14HCGL245011

Internet address is 10.100.9.2/30

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

reliability 255/255, txload 33/255, rxload 14/255

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 00:09:10

Queueing strategy: fifo

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

5 minute input rate 87000 bits/sec, 73 packets/sec

5 minute output rate 202000 bits/sec, 74 packets/sec

44660 packets input, 6309707 bytes, 0 no buffer

Received 64 broadcasts, 0 runts, 0 giants, 0 throttles

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

45575 packets output, 15320751 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

[ggatten]

Do a "show serv s0/0 perf" from privledged mode. It will show current T1 state, and a 24 hour history in 15 minute buckets - (96) 15min intervals.

This is the lowest level error reporting I know of - well, maybe show controllers - but show serv is very helpful in diagnosing these problems and reconciling down events.

Gary

[csanchez]

Thanks I will perform that!

[cool.cisco]

Hi,

As i understand from smiff is speak to telco and describe the problem.

If you are still experiencing the issues then ask them to perform end to end test in that case you will give the loop towards telco and they will put the birt meter this will verify whether some problem in the telco network or not.

Or you can ask telco to give the loop and put a birt meter in your location and see how the errors are coming...

Hope this will clarify..

Thanks,

[csanchez]

It does. Thanks for clarifying.

[cool.cisco]

rate it if it was worth for you..