Dedicated Leased Line - Intermittent Offline Problem

[fkseow]

Hi, I have the following;

HQ Office:

1x 2600 series Cisco Router

- IOS 12.X

- 1x Serial Interface

- 1x Ethernet Interface

Remote Office:

1x 2600 series Cisco Router

- IOS 12.X

- 1x Serial Interface

- 1x Ethernet Interface

The Remote Office is connected to the HQ Office by a dedicated leased line via a local Service Protocol, using the Serial Interface.

This setup has been running fine for more than a year, but recently there is always intermittent offline problem between the two offices ("Request Timed Out" when pinging from HQ to the Remote office).

When telnetting to the HQ Router Serial Interface, it shows some CRC errors.

After the local Service Provider verifying the line condition, they confirmed that nothing wrong with the line. I have also changed the entire router in HQ except the one in Remote office. Problem still persists.

Anyone please guide on how troubleshooting this.

TQ.

[a.manosca]

The following link might help:

http://www.cisco.com/en/US/tech/tk713/tk628/technologies_tech_note09186a00800a758d.shtml

[timm.benkula]

Use the show service-module serialX command and look at the Errored Secs and Unavail Secs. Check it at various times and see if the numbers are incrementing. If they are, have the service provider to do extended monitoring on the circuit.