NNMi 9.x : What can cause SNMPLinkUp/Down traps not to be seen on the SNMP trap browser from a managed device

NNMi will honor SNMPLinkUp/Down traps from managed devices provided that the interface creating these traps on the device is being polled by NNMi. If the interface is not being polled (even when the device hosting the interface is managed and polled), NNMi will not honor traps from such interface.

To confirm if the polling state of the interface is causing traps to be dropped by NNMi, enable tracing to FINEST level on 'events' using :
Windows : %NNMInstallDir%\support\nnmsetlogginglevel.ovpl com.hp.ov.nms.events FINEST
Unix : /opt/OV/support/nnmsetlogginglevel.ovpl com.hp.ov.nms.events FINEST

Once the trap reaches NNMi, the trace file* shows messages like following :

Mar 22, 2012 4:22:57.249 PM [ThreadID:188] FINE: com.hp.ov.nms.events.stages.Resolver run: Interface 2/6 with ifAlias xyz and ifIndex xyz hosted on node xyz is not monitored for fault polling. This snmp trap will be dropped.

Mar 22, 2012 4:22:57.249 PM [ThreadID:188] FINE: com.hp.ov.nms.events.stages.Resolver run: Pipeline data:
Base Configuration Id: <xyz>
Uuid: <xyz>
Id: null
Name: SNMPLinkDown
Severity: Major
Oid: .1.3.6.1.6.3.1.1.5.3
Formatted Message: Agent Interface Down (linkDown Trap) on interface $1
Source Node Uuid: <xyz>
Source Node Id: xyz
Source Node Name: xyz
Source Node Long Name: xyz
Source Node Management Address: xyz

* NNM trace file can be found at :
Windows : %NNMDataDir%\log\nnm\nnm-trace.*.*.log
Unix : /var/opt/OV/log/nnm/nnm-trace.*.*.log

In order to see messages in the SNMP trap browser in NNMi, enable 'Interface fault polling' for the interface in NNMi. For more details on 'Interface fault polling', refer to the NNMi Online Help: Help for Administrators from the link below :
http://support.openview.hp.com/selfsolve/documents