IPv4 Multicast over an IPv6 Multicast in Softwire Mesh Networks
RFC 8638

Received changes through RFC Editor sync (created alias RFC 8638, changed abstract to 'During the transition to IPv6, there are scenarios where a backbone network internally running one IP address family (referred to as the internal IP or I-IP family) connects client networks running another IP address family (referred to as the external IP or E-IP family). In such cases, the I-IP backbone needs to offer both unicast and multicast transit services to the client E-IP networks.

This document describes a mechanism for supporting multicast across backbone networks where the I-IP and E-IP protocol families differ. The document focuses on the IPv4-over-IPv6 scenario, due to lack of real-world use cases for the IPv6-over-IPv4 scenario.', changed standardization level to Proposed Standard, changed state to RFC, added RFC published event at 2019-09-09, changed IESG state to RFC Published)