China Mobile China Mobile New H3C Technologies New H3C Technologies IPv6-based tunneling technologies, such as SRv6, have been deployed by provider on transport networks to provide users with services such as VPN and SD-WAN. After the service traffic enters the provider's transport network, it will be encapsulated by tunnel (SRv6 encapsulation). In order to better meet the SLA requirements of users, some technologies need to carry relevant information along with the flow to guide the processing of packets during forwarding. This document discusses the programmability of IPv6 source addresses to carry the necessary flow information