The IP Address Translation table used for mapping from IP addresses to physical addresses. The Address Translation tables contain the IP address to 'physical' address equivalences. Some interfaces do not use translation tables for determining address equivalences (e.g., DDN-X.25 has an algorithmic method); if all interfaces are of this type, then the Address Translation table is empty, i.e., has zero entries. While many protocols may be used to populate this table, ARP and Neighbor Discovery are the most likely options.