IPv6 rapid deployment

6rd is a mechanism to facilitate IPv6 rapid deployment across IPv4 infrastructures of Internet service providers (ISPs).

The protocol is derived from 6to4, a preexisting mechanism to transfer IPv6 packets over the IPv4 network, with the significant change that it operates entirely within the end-user's ISP network, thus avoiding the major architectural problems inherent in the design of 6to4. The name 6rd is a reference to both the rapid deployments of IPv6 it enables, and, informally, the initials (RD) of its inventor, Rémi Després.

A description of 6rd principles and their first application by the ISP Free is published in RFC 5569,^[1] The 6rd specification prepared for standardization in the IETF is available as RFC 5969.^[2]