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How to resolve this problem?

I having cisco router(2600) with 2 serial interfaces. One interace s0/0 connected to 2 mpbs internet leased line and aother interface s0/1 connected to another 2 mbps internet line . Totally i m having 4 mpbs internet leased line. One interface frequently going down and up

Log messages shown below

Syslog logging: enabled (0 messages dropped, 0 flushes, 0 overruns)

Console logging: level debugging, 2339 messages logged

Monitor logging: level debugging, 0 messages logged

Buffer logging: level debugging, 2339 messages logged

Trap logging: disabled

Log Buffer (4096 bytes):

col on Interface Serial0/1, changed state to down

Mar 14 15:03:39: %LINK-3-UPDOWN: Interface Serial0/1, changed state to up

Mar 14 15:03:40: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/1, chan

ged state to up

Mar 14 15:04:28: %LINK-3-UPDOWN: Interface Serial0/1, changed state to down

Mar 14 15:04:29: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/1, chan

ged state to down

Mar 14 15:04:56: %LINK-3-UPDOWN: Interface Serial0/1, changed state to up

Mar 14 15:04:57: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/1, chan

ged state to up

Mar 14 15:07:28: %LINK-3-UPDOWN: Interface Serial0/1, changed state to down

Mar 14 15:07:29: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/1, chan

ged state to down

Mar 14 15:07:55: %LINK-3-UPDOWN: Interface Serial0/1, changed state to up

Mar 14 15:07:56: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/1, chan

ged state to up

Mar 14 15:09:30: %LINK-3-UPDOWN: Interface Serial0/1, changed state to down

Mar 14 15:09:31: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/1, chan

ged state to down

Mar 14 15:09:48: %LINK-3-UPDOWN: Interface Serial0/1, changed state to up

Mar 14 15:09:49: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/1, chan

ged state to up

Mar 14 15:11:06: %LINK-3-UPDOWN: Interface Serial0/1, changed state to down

Mar 14 15:11:07: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/1, chan

ged state to down

Mar 14 15:11:24: %LINK-3-UPDOWN: Interface Serial0/1, changed state to up

Mar 14 15:11:25: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/1, chan

ged state to up

Mar 14 15:13:25: %LINK-3-UPDOWN: Interface Serial0/1, changed state to down

Mar 14 15:13:26: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/1, chan

ged state to down

Mar 14 15:13:43: %LINK-3-UPDOWN: Interface Serial0/1, changed state to up

Mar 14 15:13:44: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/1, chan

ged state to up

Mar 14 15:14:22: %LINK-3-UPDOWN: Interface Serial0/1, changed state to down

Mar 14 15:14:23: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/1, chan

ged state to down

Mar 14 15:14:40: %LINK-3-UPDOWN: Interface Serial0/1, changed state to up

Mar 14 15:14:41: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/1, chan

ged state to up

Mar 14 15:15:33: %LINK-3-UPDOWN: Interface Serial0/1, changed state to down

Mar 14 15:15:34: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/1, chan

ged state to down

Mar 14 15:15:51: %LINK-3-UPDOWN: Interface Serial0/1, changed state to up

Mar 14 15:15:52: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/1, chan

ged state to up

Mar 14 15:17:20: %LINK-3-UPDOWN: Interface Serial0/1, changed state to down

Mar 14 15:17:21: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/1, chan

ged state to down

Mar 14 15:17:38: %LINK-3-UPDOWN: Interface Serial0/1, changed state to up

Mar 14 15:17:39: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/1, chan

ged state to up

Mar 14 15:18:52: %LINK-3-UPDOWN: Interface Serial0/1, changed state to down

Mar 14 15:18:53: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/1, chan

ged state to down

Mar 14 15:19:18: %LINK-3-UPDOWN: Interface Serial0/1, changed state to up

How to resolve this prob? I have attaced the log file as an attachment.

2 REPLIES
Hall of Fame Super Silver

Re: How to resolve this problem?

Hello Vinoth,

to troubleshoot this issue:

use

sh int ser0/1 repeatedly and save the outputs on a text editor.

Try to see if there are incrementing errors and note what type of errors are.

note also the Last input line if the time increments the link is unidirectional

to check that your serial interface is healthy use:

debug serial interface

verify that the my sequence number increments over time

Call the provider and have them perform loopback tests: the link is probably too errored or unidirectional in this moment

Hope to help

Giuseppe

Bronze

Re: How to resolve this problem?

Hi,

I would call your telco and arange a circuit test.

Regards

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