Mobile Networking within the IETF

Charlie Perkins, IBM

Within the Internet Engineering Task Force (IETF) there are a number of development activities for protocols which are relevant to mobile networking. Included among them are mobile-IP, DHCP, PPP, mobile-IPv6, and the Service Location Protocol. A description of these efforts will be given, including protocol details, current status information, and clarifying their relationships. The tutorial will explain the details of the mobile-IP model, as well as the registration protocols and tunneling mechanisms. When mobile computers attach themselves to new networks within the Internet, they can use mobile-IP as a means to achieve seamless roaming -- transparently to application software. Using mobile-IP, a mobile client supplies information to a router, called its home agent, about its current whereabouts using a simple registration protocol. Once the basic operation has been shown, additional mechanisms will be described to avoid the need for routing packets through the (possibly distant) home agent, providing a faster route between mobile clients and their correspondents. The Dynamic Host Configuration Protocol (DHCP) will then be introduced and its usefulness for mobile users explained. After describing the basic DHCP client/server model, I'll apply it in some likely scenarios for mobile computing, and show the advantages and the disadvantages of using DHCP. Perhaps even more than static computers, mobile computers will be used by people uninterested in performing administrative duties, and I will describe the use of a new option for DHCP which allows the acquisition of IP addresses appropriately configured for use with the mobile-IP protocols. Having covered the basics of mobility for IP version 4, I will describe IP version 6 and its provisions for mobile computing. I'll give enough details about IPv6 to make the discussion self contained, and then describe in detail the mobility messages. Architectural differences between IPv4 and IPv6 mobility will be presented, and the requirements for IPv6 hosts, routers, and mobile nodes will be enumerated. Interactions between mobility for IPv6 and other parts of the IPv6 protocol suite (such as Neighbor Discovery) will also be described. A final description will be of the Service Location Protocol (SLP), designed to eliminate additional configuration requirements that otherwise might require manual configuration by the users. For instance, a user would often need to find out which local printers can handle Postscript output, and where local mount points can be found for local libraries and other support data.

Biographical Sketch

Charles Perkins (perk@watson.ibm.com) is a research staff member at IBM T.J. Watson Research, investigating mobile and ad-hoc networking, resource discovery, and automatic configuration for mobile computers. He is serving as the document editor for the mobile-IP working group of the Internet Engineering Task Force (IETF), and serves on the editorial boards for ACM/IEEE Transactions on Networking, ACM Wireless Networks, and IEEE Personal Communications. Charles holds a B.A. in mathematics and a M.E.E. degree from Rice University, and a M.A. in mathematics from Columbia University.