tailieunhanh - IP for 3G - (P4)

Multimedia Service Support and Session Management Two of the key new features of 3G networks are their ability to support multimedia applications and the Virtual Home Environment. The former implies a network with the ability to support more than just voice communications (and more than just non-real-time, data applications like the World Wide Web and e-mail). | IP for 3G Networking Technologies for Mobile Communications Authored by Dave Wisely Phil Eardley Louise Burness Copyright 2002 John Wiley Sons Ltd ISBNs 0-471-48697-3 Hardback 0-470-84779-4 Electronic 4 Multimedia Service Support and Session Management Introduction Two of the key new features of 3G networks are their ability to support multimedia applications and the Virtual Home Environment. The former implies a network with the ability to support more than just voice communications and more than just non-real-time cS iSs appi cations iike the World Wide Web and e-mail . The latter is where users of 3G networks store their preferences and data. In its original sense as described in Chapter 2 the VHE is responsible for tailoring the communications to the physical connection and terminal currently being used. This chapter considers how this type of functionality could be provided in an IP network. It begins with a discussion of the key concept of session management. A multimedia communication such as a videoteelephony calir r eVr n c d to as a eession. There are a number of different functions that are required to provide and support sessions. This chapter focuses particularly on the session management control plane functions. Other aspects of session management the data plane are introduced in the first section but are discussed further within Chapter 6. Following this we briefly coniider how curtenrly testions and VHE functionality are handled in both 2G R99 UMTS systems and the Internet. Within the Internet ccntool plnne s o n mnnagemont for eeal-time multimedia services is an area that is still under development. The two main protocols for this role are reviewed. is currently in use today wheeeas the Session Initiation Protocol SIP is a newer IETF standard. SIP is included in the next generation of UMTS standards. Its operation is then examined in some detail. The chapter then goes on to look at some examples of the power of SIP how it codd be put to .