RFC8950: Announce IPv4 with an IPv6 next-hop

RFC 8950 is a new Internet Engineering Task Force (IETF) specification that introduces a new extension to the IPv4 protocol. This extension allows an IPv6 next-hop to be associated with an IPv4 address. The new extension is used in the Source and Destination Option (S/D) header of IPv4 packets. It is used to advertise the next-hop IPv6 address when an IPv4 router decapsulates a packet from an IPv6 packet. The motivation behind this extension is to support the transition from IPv4 to IPv6. The new extension is optional, and it does not require any changes to existing IPv4 routers. The specification was published on June 1, 2023, as RFC 8950. The author of the specification is Anoop Ghanwani, and it was developed by the IETF's IPv4 Maintenance and Extensions (6MAN) working group.