Proxy Mobile IP (PMIP) provides a solution for networkbased localized mobility management which in contrast to host-based mobility solutions, like Mobile IP (MIP), does not require changes to the end-hosts. It also avoids tunneling overhead on the interface which connects a mobile node to it’s access network. Within a PMIP-enabled mobility domain, the mobile node is able to maintain the same IP address when it moves. However, if the mobile node leaves this domain the mobility support breaks. In this paper we propose an extension to PMIP, called IPMIP which allows to interconnect multiple PMIP-enabled mobility domains to provide continuous mobility support for a mobile user. The I-PMIP architecture provides the mobile node with an anchor point that is placed very close towards the mobile node. Numerical analysis show that our networkbased approach is comparably efficient to host-based mobility solutions. Categories and Subject Descriptors C.2.1 [Computer Systems Organization]: Comput...