ABSTRACT
Session Initiation Protocol (SIP) was originally designed as an Internet Protocol for establishing and maintaining multimedia sessions. It, however, gained prominence recently as a Voice-over-Internet Protocol (VoIP) signaling protocol. In addition to its signaling capabilities, SIP can also act as an application layer mobility protocol supporting various flavors of mobility. In this chapter, we first argue in favor of the virtues of SIP in handling mobility in heterogeneous networks and then present a comprehensive performance study of a SIP-based vertical handoff scenario in third generation (3G) networks, where we show that performance-wise SIP may not meet the expectations of the 3rd Generation Partnership Project (3GPP)-specified standards. We conclude the chapter with covering some of the auxiliary schemes that help SIP meet the standard specified requirements.
