This document describes the Network Mobility (NEMO) Basic Support protocol that enables Mobile Networks to attach to different points in the Internet. The protocol is an extension of Mobile IPv6 and allows session continuity for every node in the Mobile Network as the network moves. It also allows every node in the Mobile Network to be reachable while moving around. The Mobile Router@ which connects the network to the Internet@ runs the NEMO Basic Support protocol with its Home Agent. The protocol is designed so that network mobility is transparent to the nodes inside the Mobile Network.