TABLE OF CONTENTS This is the first of three chapters covering the big three network-level challenges in wireless IP networks, namely mobility, QoS, and security. This chapter introduces the problems associated with mobility, as well as various mobility concepts, such as handoffs and location management, types of mobility (personal, terminal, session, and service), and L2 versus L3 mobility. The text explains our focus on the subproblems having to do with finding a wireless device (e.g., for routing, session initiation) even though it may move from time to time, whether before or even during sessions. The Mobile IP protocol is introduced as a well-established solution, and assessed. Enhancements such as route optimization, micromobility, and fast handoffs are introduced as ways to correct shortcomings of Mobile IP. Micromobility schemes discussed include hierarchical Mobile IP, host-based schemes like Cellular IP, and intrawireless LAN mobility. We discussed SIP-based mobility as an application-layer alternative to Mobile IP, and TCP migration and MSOCKS as transport-layer alternatives.
