China Telecom China Telecom Viagenie The IPv6 transition has been an ongoing process throughout the world due to the exhaustion of the IPv4 address space. However, this transition leads to costly end-to-end network upgrades and poses new challenges of managing a large number of devices with a variety of transitioning protocols. While IPv6 transition tools exist, there are still new issues exist. Operators may need various types of IPv6 transition technologies depending on performance requirements, deployment scenarios, etc. To address these difficulties, a software defined unifying approach would provide a unified way to deploy IPv6 in a cost-effective, flexible manner. This document describes use cases of IPv6 transition (Openv6) and also requirements in SUPA architecture.