VOiCOM VoIP Standards

Proxy CSCF - this is the first point of contact in a visited network and will find the user's home network and provide some translation, security and authorization functions
Serving CSCF - controls sessions, acts as registrar and triggers and executes services. The serving CSCF will access the user's profile. It can be located in the home or visited network
Interrogating CSCF - the first point of contact in the home network. It assigns the serving CSCF, contacts the HSS and forwards SIP requests.

Note:

The links and documents found on this page refer to standards, proposals and draft standards. Whilst we endeavor to post the most recent versions, please refer to the IETF RFC's ITU SG16 and W3C for latest status

Related IETF and SIP RFC's (Click)

IETF 3GPP2 - Standardization Collaboration - 3131
Private Header Extensions for 3GPP - 3455
SIP, IPv6 and 3GPP - 3314

The 3rd Generation Partnership Project (3GPP) is a collaboration agreement that was established in December 1998. The collaboration agreement brings together a number of telecommunications standards bodies which are known as “Organizational Partners”. The scope of the 3GPP is to globalize and standardize the availability of mobile / radio networks and technologies - Universal Terrestrial Radio Access (UTRA). 3GPP 'leans' on SIP to provide call and service signalling from terminals and between network nodes. The 3GPP 'Internet Multimedia Sub System" and applications services are SIP based, with URL's or E.164 addressing users.

3GPP has identified the Call State Control Function (CSCF) in the network. This is the equivalent of a SIP server. There are three different types of CSCF: