Symptom

OSPF neighbor retransmissions can occur intermittently when the NSR feature is used.

Conditions

This is a known consequence of the delayed flooding using NSR with OSPF due to the sync of LSA to the standby RSP. The behavior does not cause any side effects, ie. no additional SPF or any computation is carried out because the retransmitted LSA was already received by the neighbor anyway. Nevertheless, the additional retransmissions can lead to unnecessary operational concern, particularly if SNMP traps are activated for OSPF retransmissions.

Workaround

Apart from disabling NSR, there is no workaround. Disabling OSPF SNMP retransmission traps could be done where the problem is acute, but with the risk of missing a valid/faulty retransmission condition.

Further Problem Description