(looped) display in ATM interface

karmesh_12 · ‎09-09-2008

As far as we know, when the Telco provided a loop in our interface we are able to see the word(looped) in the interface. It means the conneection is being looped and testing are going on. However, I was informed by telco staf that we are unable to see this word while troubleshoooting for ATM interface. in fact, today, I faced the same issue when the Telco requested me to check for a loop and I were not able at all to see them. They only informed me that you wont be able to see it if ATM interface. The main thing I want to know is WHY. Is it something to do with Cells as ATM uses celss for transmission and not packets or due to Virtual Circuit Identifier (VCI)/VPI ? If anyone have the info, please let me know. Thanks in advanced.

Giuseppe Larosa · ‎09-09-2008

Hello Karmesh,

you are in the right direction ATM cells use vpi/vci.

However, ATM framework provides for special purpose ATM cells that are called OAM cells: some type of OAM cells can be used to perform logical loopback tests I think OAM F4 or OAM F5.

What you need is to enable OAM management on the atm interface

see the following link to oam

http://www.cisco.com/en/US/docs/ios/atm/configuration/guide/atm_oam_f5_cnck_ps6350_TSD_Products_Configuration_Guide_Chapter.html

or the ATM OAM ping

http://www.cisco.com/en/US/docs/ios/atm/configuration/guide/atm_oam_ping_ps6350_TSD_Products_Configuration_Guide_Chapter.html

Hope to help

Giuseppe