Juniper SYSTEM BASICS - CONFIGURATION GUIDE V 11.1.X Configuration Manual page 271

Chapter 4: Configuring SNMP
Unknown security models Number of SNMP PDUs with unrecognized
security
Unavailable contexts Number of SNMP proxy requests to unknown
entities
SNMP packets out Total number of SNMP packets sent by the router
Too big errors Number of processed PDUs that resulted in SNMP PDUs
too large to encode
No such name errors Number of requests that resulted in noSuchName
errors. If interfaces configured on modules that do not support 64-bit
counters are accessed, the system returns a noSuchName message.
Bad values errors Number of requests that resulted in badValues errors
General errors Number of general errors
Get-response PDUs Number of requests that resulted in getResponse
PDUs
SNMP trap PDUs Number of SNMP trap PDUs generated by this agent
SNMP trap proxied Number of traps generated by this agent that are
sent via trap-proxy
Invalid Message Report PDUs Number of packets received by the SNMP
engine that were dropped because there were invalid or inconsistent
components in the SNMP message
Unknown PDU Handler Report PDUs Number of packets received by
the SNMP engine that were dropped because the PDU in the packet
could not be passed to an application responsible for handling the PDU
type; for example, no SNMP application had registered for the proper
combination of the context engine ID and PDU type
Unknown Context Report PDUs Number of packets received by the
SNMP engine that were dropped because the context contained in the
message was unknown
Unsupported Security Level Report PDUs Number of packets received
by the SNMP engine that were dropped because they requested a security
level that was unknown to the SNMP engine or otherwise unavailable
Not in time Window Report PDUs Number of packets received by the
SNMP engine that were dropped because they appeared outside the
authoritative SNMP engine window
Unknown Username Report PDUs Number of packets received by the
SNMP engine that were dropped because they referenced a user that
was not known to the SNMP engine
Unknown Engine ID Report PDUs Number of packets received by the
SNMP engine that were dropped because they referenced an
snmpEngineID that was not known to the SNMP engine
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Monitoring SNMP