China Telecom ZTE Corporation ZTE Corporation France Telecom This document specifies a new Remote Authentication Dial-In User Service (RADIUS) attribute to carry the Multicast-Prefixes-64 information, aiming to delivery the Multicast and Unicast IPv6 Prefixes to be used to build multicast and unicast IPv4-Embedded IPv6 addresses. this RADIUS attribute is defined based on the equivalent DHCPv6 OPTION_v6_PREFIX64 option.