Question

A network monitoring server performs SNMP GETBULK walks against a core router every 5 minutes. Recently, the NMS reports intermittent timeouts and partial MIB tables, but pings and SSH to the router remain stable. On the router, 'show policy-map control-plane' shows the SNMP class with a growing number of dropped packets under 'exceed', while the 'conform' counter also increases. The class matches ACL traffic to UDP 161. What is the MOST likely cause of the intermittent SNMP failures?

Accepted Answer

The CoPP policer's CIR for the SNMP class is set too low, so bursts of GETBULK response processing exceed the rate and packets are dropped by the exceed action

Answer

The CoPP class ACL is matching UDP 161 instead of UDP 162, so trap traffic is being policed incorrectly

Answer

SSH and ICMP share the same policer class as SNMP, causing contention that only affects SNMP

Answer

The control-plane policy is applied in the output direction, so inbound SNMP polling is never evaluated by CoPP