KDDI Lab Cisco ETRI ETRI Cisco A Virtual Interface is a software semantic internal to the host operating system. This semantic is widely available in all popular operating systems and is used in various protocol implementations. The Virtual Interface support is also required on the mobile node operating in a Proxy Mobile IPv6 domain, for leveraging various mobility features such as inter-technology handoffs, multihoming and flow mobility support. This document explains the operational details of Virtual Interface construct and the inter-working with the network elements in the Proxy Mobile IPv6 domain for supporting various network-based mobility management features.