Cisco SIP Gateway device showing as Disabled when it is actually Active - root cause and solution

[David_Sun]

When monitoring Cisco SIP Gateway, Prognosis shows its ISDN Serial devices as Disabled whilst it is actually Active and running, the symptom looks as below.

Prognosis uses SNMP polling to get the IfType OID from the If-MIB to determine if the device type is to be picked up, if the type is the expected type, Prognosis will then get the IfAdminStatus and IfOperStatus and figure out the overall status of the device. In this case, the IfType OID returns rs232 which is not correct type for the ISDN Serial device (should be ds0 (81)), as a result Prognosis does not poll the IfAdminStatus and IfOperStatus OIDs for each channel and mark this device as Disabled.

This has been identified as a Cisco IOS issue, it has been resolved in IOS 16.9.5 

With IOS 15.5(3) and earlier, bearer channels of an ISDN-PRI circuit returned ifType of ds0 (81).  With IOS 16.9.1, the bearer channels of an ISDN-PRI circuit return ifType of rs232 (33).

Recommendation: upgrade the IOS on the SIP gateway to v16.9.5 or later. The device status will show correctly as up.

[SCOTT_BALDWIN]

The Cisco reference number is: CSCvm25921: "Signaling interface inactive on "show snmp mib ifmib ifindex de"

[David_Sun]

Thank you Scott.