Description: Table of mappings from the internal to external address. By definition, this is a snapshot of NAT instance state at a given moment. Indexed by NAT instance, internal realm, and internal address in that realm. Provides the mapped external address and, depending on implementation support, identifies the address pool from which the external address and port were taken and the index of the subscriber to which the mapping has been allocated.

In the case of DS-Lite (RFC 6333), the indexing realm and address are those of the IPv6 encapsulation rather than the IPv4 inner packet.