MobileNAT: A New Technique for Mobility Across Heterogeneous Address Spaces

We propose a new network layer mobility architecture called Mobile NAT to efficiently support micro and macro-mobility in and across heterogeneous address spaces common in emerging public networks. The key ideas in this architecture are as follows: (1) Use of two IP addresses – an invariant virtual IP address for host identification at the application layer and an actual routable address at the network layer that changes due to mobility. Since physical address has routing significance only within a domain, it can be a private address and therefore, does not deplete the public IP address resource. (2) New DHCP enhancements to distribute the two addresses. (3) A new signaling element called Mobility Manager (MM) that uses Middlebox Communication (MIDCOM) framework to signal the changes in packet processing rules to the Network Address Translators (NATs) in the event of node mobility. Our proposal does not require any modifications to the access networks and can seamlessly co-exist with the existing Mobile IP mechanisms and therefore, can be used to provide seamless mobility across heterogeneous wireline and wireless networks. We report implementation details of a subset of our ideas in a testbed with Windows XP clients and Linux based NATs. Milind M. Buddhikot is a Member of Technical Staff in the Center for Networking Research at Lucent Bell Labs, Holmdel, NJ. Milind holds a Doctor of Science (D. Sc.) in computer science (July 1998) from Washington University in St. Louis, and a Master of Technology (M.Tech.) in communication engineering (December 1988) from the Indian Institute of Technology (I.I.T), Bombay. His current research interests are in the areas of systems and protocols for integrated public wireless networks, authentication and dynamic key exchange protocols, Voice-over-IP (VOIP) networks, and sensor and ad-hoc networks. He has authored over 26 research papers and 9 patent submissions in the areas of design of multimedia systems and protocols, layer-4 packet classification, MPLS path routing, authentication and dynamic key exchange, and 802.11/3G integration. Milind currently serves as the Associate Editor of the IEEE/ACM Transactions on Networking. He also served as a co-guest-editor of IEEE Network magazine’s March 2001 Special issue on Fast IP Packet forwarding and Classification for Next Generation Internet Services. He has served in the capacity of a tutorial chair for IEEE LCN 94, 95, as a publicity chair for NOSSDAV97, and as a program committee member for MMCN 2001, 2003, IEEE ICNP2002, 2003 and IEEE LCN 93-2000 conferences. Adiseshu Hari received a Doctorate in Computer Science from Washington University in St. Louis in 1999, and has since been at Bell Labs, Lucent Technologies, where he’s worked on projects related to network design and optimization. He’s currently looking at design issues in large scale SIP based VoIP networks. Kundan N. Singh received a B.E.(Hons) degree in Computer Science from Birla Institute of Technology and Science in India, M.S. in Computer Science from Columbia University, and is continuing his studies towards Ph.D. degree in the same field at Columbia University in New York City. As a research assistant in the Internet Real-Time Lab at Columbia University, he is doing research on Internet telephony, SIP-H.323 signaling gateway, unified messaging systems and multimedia conferencing. Scott Miller is the Director of the High Speed Mobile Data Research department at Bell Labs in Holmdel, New Jersey. He has B.S. and M.S. degrees in electrical engineering from Cooper Union in New York City. His current research involves the integration of 802.11 and 3G wireless data service and the related mobile networking issues concerning seamless mobility, authentication, security, roaming, and accounting. Prior to his work on 802.11/3G integration, Scott has led several systems research efforts in wireless applications, implementing novel systems for wireless messaging, speech-driven directory services, wireless instant messaging, carrier-based content billing, and multi-media content adaptation.This revised version was published online in August 2005 with a corrected cover date.