Our own Niels Widger wrote an in-depth article for EDN Network on the MAP-E protocol and how it allows broadband ISPs to support legacy IPv4 networks on the subscriber’s premises while still using IPv6 in their core network:
Internet service providers (ISPs) are running out of public IPv4 addresses and want to move away from IPv4 in their internal network. Mapping of Address and Port with Encapsulation (MAP-E), an IPv6 transition mechanism for transporting IPv4 packets across an IPv6 network using IP encapsulation, lets ISPs provide IPv4 services without deploying a full dual-stack network. MAP-E saves money on network upgrades and speeds the migration to IPv6. MAP-E also helps relieve the issue of IPv4 address exhaustion by letting multiple CPE’s share the same public IPv4 address through a form of Carrier-Grade NAT (CGN).
This article discusses the mechanisms that MAP-E needs to function, explains the MAP-E configuration options and how they can be provisioned, and describes what you should test when developing a MAP-E implementation.