Controller Errors

[carthique]

Hi Everyone,

currently we are using cisco 2951 series router,we saw errors in one the WAN interface that ie.. Se0/2/0 and as our ISP suggested,we moved the circuit from Se0/1/0,but still we are seeing errors in the interface and controller port also,

Please Suggest me,what could be the issue and steps to proceed,

Note:ISp advised,they are seeing errors from controller in T1 0/2/0,so we moved to T1 0/1/0

[Richard Burts]

If you were seeing errors on a circuit connected to one serial interface then it was good troubleshooting to move it to a different interface. If the problems moved with the connection then it certainly suggests that the problem was not the original interface.

You have not told us what kind of errors and not what kind of circuit and not how the interface is configured. So it is difficult to give good advice about what the problem is. If you provide better information for us to work with then we might be able to give you better advice.

HTH

Rick

[carthique]

Hi rechard,

we are seeing input and CRC errors on the serial interface and some code violations on the controller and it is T1 link

[Leo Laohoo]

we are seeing input and CRC errors on the serial interface and some code violations on the controller and it is T1 link

Post the complete output to the command "sh interface <PORT>". 

Contact the ISP and request for an end-to-end Bit Error Rate (BER) test to be conducted from your premises (not software-driven BER test).  Book the time for a 6-hour instead of the "quickie" 1-hour, in most cases, isn't sufficient enough time to see the errors.

[carthique]

Hi Leo,

ISP did intrusive testing and passive monitoring,in both it is clean from their end ,not sure whether they are going to this test or not,we should not reveal the information regarding the port or any 

[zaheer.jahangir1]

Kindly check the framing from ISP end there is 2 type of framing for the controller
CRC-4 and no-CRC-4, deactivate the controller and check if the controller comes back up after this check or not, u may check it as show isdn status, if still the issue is not resolved better try to check your firmware of the device and check the compatibility of it with the controller as in some cases after an upgrade things don't work normally.

Rate the correct/helping answer.

Regards,
Zaheer Jahangir
0097450667490

[Leo Laohoo]

ISP did intrusive testing and passive monitoring,in both it is clean from their end ,not sure whether they are going to this test or not,we should not reveal the information regarding the port or any 

I've troubleshooted a lot of Frame Relay (and older) links in the past and until now, unless the ISP is using HARDWARE-based BER tests, any software-based "intrusive" testing is next to useless as the software-based protocols have very huge differential accuracy.  What hardware-based BER tests can pick up does not guarantee the software-based BER testers can too.

ISPs are reluctant to perform hardware-based BER tests for the following reason:

1.  It's manual intensive - ISP need to send one tech to the site and another to the nearest exchange and initiate the test.

2.  The hardware to perform BER is very expensive and, in some cases, heavy.  Trying to train someone is also difficult.  

3.  Accuracy - ISPs don't care if the link is getting CRC errors.  The link works.  The subscriber pays.  

[joshua.wilson]

Hey Carthique

Did the ISP test your T1 circuit?   Also did you test your T1 0/2/0 locally on the router?

HTH

Joshua