usrInverseARPAge reports how long this dynamically-learned Inverse ARP cache entry has been aging toward the configured maximum in usrInverseARPMaxAge, per its description "The current timeout age of an entry". An admin can read this to see how close a dynamic mapping is to being aged out of the cache, and can also write it to manually adjust or reset an individual entry's age. For example, if usrInverseARPMaxAge is set to 4 transmit-interval counts and this entry's usrInverseARPAge reaches 3, an admin would know the mapping is about to be purged unless refreshed by another Inverse ARP exchange.