The 7750 SR supports Network Address (and port) Translation (NAPT) to provide continuity of legacy IPv4 services during the migration to native IPv6. By equipping the multi-service ISA (MS ISA) in an IOM3-XP, the 7750 SR can operate in two different modes, known as:
Large Scale NAT
Layer 2-Aware NAT
These two modes both perform source address and port translation as commonly deployed for shared Internet access. The 7750 SR with NAT is used to provide consumer broadband or business Internet customers access to IPv4 Internet resources with a shared pool of IPv4 addresses, such as may occur around the forecast IPv4 exhaustion. During this time it, is expected that native IPv6 services are still growing and a significant amount of Internet content remains IPv4.