China Telecom China Telecom CERNET Center/Tsinghua University Huawei Technologies KPN This document defines a new type of segment for Segment Routing, 4map6 segment, along with its corresponding End.4map6 endpoint behavior. This behavior performs stateless IPv4/IPv6 translation or encapsulation at PE nodes based on stateless mapping rules, thereby enabling the delivery of IPv4 services over an IPv6-only network. At the same time, the BGP Prefix-SID attribute SRv6 Service TLVs is extended to transmit IPv4/IPv6 address mapping rules in IPv6-only domain and cross-domain.