I have a 2611 w/ a 56k csu/dsu conn

[Dirk186]

I have a 2611 w/ a 56k csu/dsu connecting to a 2524 w/ 56k csu/dsu over a 56k DDS line. Upon a show int s0/0 in the 2611 it shows many CRC and input errors, which leads me to my problem. The line goes up and down constantly during the day. The telco has tested the line numerous times only to find nothing. The 2611 csu/dsu has been replaced as well as the one on the 2524. Both are set to HDLC encapsultation and clocking is set to line. The 2524 shows half the errors than the 2611. All cables and connectors have been tested and replaced. IOS in 2611 is 12.0 and IOS in 2524 is 11.0. Does anybody have any ideas, suggestions, similar problems? I really can't think of what else to do. Thanks.

JR

 

[rburke]

My only suggestion would be the cables and connectors, they are usually the cause of transmission errors(CRC and input). If you are positive it isn't the cables then you might want to contact telco again just ot make sure the lines at the 2611 and the 2524 are in good working order. Just my idea.....

burke

 

[techkiwi]

Has your telco tested remotely only (ie they test from the exchange out to each DSU separately)? If so, you might get them to do an "end-to-end" BER test, where a technician actually goes to each end of the circuit and they send a test pattern to each other using special testing equipment which will measure any line errors. If your telco is unwilling to send two techs out, the next best option is for them to send one tech to one end and test to a loopback plug on the other DSU.

As an ex-telco tech who used to do this for a living, I know that sometimes doing this will pick up weird errors or misconfigurations that other testing won't do. Also the techs can check out the DSU's to make sure they are configured okay.

Graham
New Zealand

 

[Dirk186]

Thanks for the help guys. The telco actually sent two techs to both ends of the line and ran tests to no avail. They also ran remote loopback tests from the telco and still found nothing. The errors on the 2611 double that of the 2524. That is what is puzzling. All of the cabling and jacks were just shortend and replace on the 2611 end too.

 

[IPKONFIG]

Call Cisco TAC output errors can indicate a bat port on your router also. Especially since you've checked all the obvious issues first.