Keio Univ./WIDE The NEMO Basic support protocol [1] specifies the operation of a Mobile Router. The Mobile Router has a bi-directional tunnel to its Home Agent through which it reverse tunnels all traffic. When the Mobile Router roams and connects to an access network that only implements IPv4, it needs to use IPv6 transition tunneling mechanisms to reach its Home Agent. This will result in a NEMO tunnel inside a transition tunnel. This document describes protocol extensions to the NEMO Basic support protocol to maintain IPv6 connectivity for the Mobile Router via its Home Agent with IPv6-over-IPv4 encapsulation with no special boxes to be deployed anywhere in the network.