SMARTS NPM: OSPFNeighborRelationship down event wasn't created

Products

• VMware Smart Assurance

Issue/Introduction

Symptoms:


The OSPF missed a OSPFNeighborRelationship down event.  It is seen in the device log the following:

Feb 20 19:33:21 GMT: %OSPF-5-ADJCHG: Process 65289, Nbr 163.35.179.137 on GigabitEthernet0/3 from FULL to DOWN, Neighbor Down: Dead timer expired

Environment

VMware Smart Assurance - SMARTS

Cause

The system/device interpreted a neighbor down occurred because timeout occurred. Assuming that router stops receiving OSPF packets from its neighbor on both router interface leading to each other. As a result, the interface from both side will stay up and the OSPF neighbor relationship on both router goes down. In this state, the NeighborState1 and NeighborState2 of this relationship becomes UNKNOWN on both side. This generate no OSPF down event. The key here is the device log s message that  Dead timer expired .

Resolution

When two end of a relationship is UNKNOWN, NPM domain manager cannot generate an alarm. This behavior cannot be changed.

Additional Information

UNKNOWN is a default state and doesn't indicate Relationship is DOWN.
SNMP might be unresponsive resulting in the endpoint state being UNKNOWN.
Traffic has not started can result in endpoint state being UNKNOWN
UNKNOWN is a startup state thus we do not generate events on.
Device being unreachable can result endpoint state being UNKNOWN