5.3.2. When to Turn NBP names into DDP addresses

When an SNMPv2 entity uses a cache entry to address an SNMP packet, it should attempt to confirm the validity mapping, if the mapping hasn't been confirmed within the last T1 seconds. This cache entry lifetime, T1, has a minimum, default value of 60 seconds, and should be configurable.

An SNMPv2 entity acting in a manager role may decide to prime its cache of names prior to actually communicating with another SNMPv2 entity. In general, it is expected that such an entity may want to keep certain mappings "more current" than other mappings, e.g., those nodes which represent the network infrastructure (e.g., routers) may be deemed "more important".

Note that an SNMPv2 entity acting in a manager role should not prime its entire cache upon initialization - rather, it should attempt resolutions over an extended period of time (perhaps in some pre- determined or configured priority order). Each of these resolutions might, in fact, be a wildcard lookup in a given zone.

An SNMPv2 entity acting in an agent role must never prime its cache. Such an entity should do NBP lookups (or confirms) only when it needs to send an SNMP trap. When generating a response, such an entity does not need to confirm a cache entry.