We propose the adaptive addresses under a hierarchical network structure, which can be realized in a newer generation of IP protocol (i.e., IPvn). It minimizes the communication overhead, enables arbitrary address space extension, simplifies both the network data-plane and control-plane, and supports better network security. More importantly, it supports incremental deployment from the network edge and gradual growth towards the core. A clear boundary between IPvn domain and the existing IPv4/IPv6 networks enables transparent cross-domain communication. The clear evolution path makes pre-standard deployment possible. We design both control plane and data plane, prototype the routers within and on the edge of an IPvn domain, and evaluate the performance. We open source the project to encourage further investigation and development.