The SNMP MIB entry ipNetToMediaPhysAddress gives the MAC address from the ARP table, referenced by the IP. Is there a table available anywhere in some router MIB that would give the equivalent of "MediaPhysAddressToipNet" (reverse) information so that an IP address in the ARP table could be referenced using the MAC address?
RFC1213 section 3.6 alludes to a future document that would define a MIB for CLNP and it would contain two tables for mappings in both directions. But I've not been able to find anything else about that.
I'm trying to avoid pulling the entire ARP table from the router (several thousand entries makes it take about 90 seconds and it drives the CPU to 100%) just to get a single MAC-to-IP address mapping when that info is needed.