Abstract: This chapter focuses on the 3GPP IP multimedia subsystem (IMS), which in addition to the core session initiation protocol (SIP) specification incorporates many SIP extensions and SIP network functions. The 3rd generation partnership project (3GPP) is a collaboration agreement signed in 1999 by a number of telecommunications standards bodies. The main aim of 3GPP is the specification of a third-generation mobile system comprising W-CDMA and TD-CDMA radio access and an evolved GSM core network. The IMS is based on the SIP protocol and architecture, and the complete solution for the support of IP multimedia applications consists of IMS-enabled user equipment (UE), an access network and PS domain providing IP connectivity, and the IMS network. 3GPP decided to base the IMS on the capabilities of SIP so that the Internet flexibility for delivering services can be brought to the telecom environment, which in turn will create new services and business opportunities. The first IMS element is the user's home SIP server or, in IMS terminology, the serving call session control function (S-CSCF). The S-CSCF incorporates basic registrar and proxy functionality but adds some additional functions such as authentication, user profile, originating calls, service control, and prohibition of media types. In IMS, the end user is assigned two identities instead of just one, where the first one is called the private user identity (IMPI), which represents the identity that is authenticated by the network, and the second one is called the public user identity (PUI).
Publication Year: 2008
Publication Date: 2008-01-01
Language: en
Type: book-chapter
Indexed In: ['crossref']
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