Understanding the telco

[dozier]

Hi,

We utilize 56k frame relay circuits for our customers that we purchase through AT&T. They are currently working on a problem with one of the circuits and I was hoping to get some insight into what they are talking about.

They are able to loop up the NI and CSU and run test patterns clean to each. I understand, that. Then they try to run a test PVC to the NI and CSU which they are not able to do--they get transmit only, no receive. I'm not sure what running a test PVC to a loop really means, so I'm not sure what this failure would indicate. Any information would be appreciated, thanks.

 

[ilil]

Check the LMI type. You have to pass the same LMI type as your carrier does, or it wont talk to thier router. They may be testing ok on the continuity side, but in order for you to "talk" to thier router, and your other side, the LMI type has to be set right. Your 3 choices are Cisco (sometimes called "LMI" by the telco), ANSI (used if you are not using a cisco router, you have to tell the telco that), or q933 ( which I have never run into).

 

[jeter]

NI mode is a test from the telco company. One way traffic I would guess is them sending but not receiveing. That is becuase LMI is not up. ILIL is correct the DLCI probably 16 needs to match the carrier. Normal is ansi.

Do a sh int and look at the serial interface.
ALso sh frame-relay pvc
look at the DLCI it will show active, inactive, or deleted.

post a config minus password info and advise what should be the lmi and dlci info and we should be able to figure it out.

“Reserve your right to think, for even to think wrongly is better than not to think at all”

Fisher CCNP,CCNA Network+