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Confirming a physical disconnection with SNMP


Dear All,

In an upcoming project, i will need to know if a cable has be physically disconnected from the router. Are there any SNMP traps for this particular event? If I recieve a linkdown from IF-MIB and check if the value of cieIfOperStatusCause from CISCO-IF-EXTENSTION is linkfailure, will i be able to confirm that a cable has been disconnected phyiscally?

Thanks in advance.


4 Replies 4


So there are no ways to do this with SNMP?

I have read the datasheets you provided.

I will be using SRE so i guess the ISR one will suit me better.

Can it be installed with SRE-V on the same SRE module?

Also, will it be possible to write a custom C/C++ application running on the SRE-V to recieve information from NAM?

Thank you for your help!

Sorry for the previous reply, I was looking at the wrong screen. At any rate in regards to your primary questions about traps for physical disconnect. Do the following on the device:

snmp-server enable traps snmp linkup linkdown coldstart

This should notify you when the link is physically disconnected with a linkdown trap and when connected again with a linkup trap.

There is a known bug for older IOS trains that did not generate the linkdown trap when the cable was disconnected. The bug id is CSCsg24215 SNMP linkdown traps not generated in 12.2(33)SRA1.


Does this trap specifically detect physical disconnections?? Are there any cases where linkdown trap will be thrown eventhough the cable was not physically disconnected?

This trap will detect any linkup or linkdown triggers.

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