Stateful redundancy for deterministic carrier-grade network address translation (NAT) services

A carrier-grade network address translation (NAT) gateway system includes a switch having a gateway function configured to receive packets that are communicated via its ingress and egress ports. The switch having the gateway function has a first link to a first NAT processing function and a second link to a second NAT processing function. The first NAT processing function has a first deterministic address/port translation function and a first mapping table for storing first binding entries. The second NAT processing function has a second deterministic address/port translation function and a second mapping table for storing second binding entries. Preferably, the first and the second deterministic address/port translation functions are the same. The switch is configured to communicate each received packet for processing at both the first and the second NAT processing functions (e.g., in either a serial manner or a parallel manner), which provides redundancy in state information.