IMS-oriented brew

In the development trend of network convergence, 3GPP, ETSI and ITU-T are both studying the IMS-based network convergence Scheme, which aims to make IMs a general platform based on SIP session, it also supports various fixed and mobile access methods to achieve convergence between fixed and mobile networks. For example, the integration of mobile network, PHS and fixed network resources to provide voice data services has changed the competition between these networks, and they have become a complementary relationship. IMS (ipmu-timediasubsystem) is a subsystem proposed by 3GPP in release5 to support IP multimedia services. Its core feature is sip and access independence. At present, IMS supports 2G and 3G mobile access methods, and does not support fixed access methods.

IMS is a PS-domain Multimedia Control/call control platform that supports session and non-session multimedia services and provides a universal service enabling platform for future multimedia applications, it is an important step to provide system evolution for all IP network services. IMS-based fixed/mobile network convergence businesses are recognized mainly because IMS has two basic points: Technology convergence point IP address and business Convergence Point Multimedia. IMS's biggest contribution to the telecom industry is the development of a solution that allows operators to immediately upgrade their networks without having to discard existing devices, so that investment in circuit switching and IP technology can be reused.

In addition to low-cost advantages for normal business environments, the ability to develop new businesses is one of the most attractive highlights of IMS. IMS uses the initial session protocol to create a unified business environment for signaling, application server integration, call session control, owner user server, and multimedia resource functions; real-time multimedia services can be provided by integrating different media (voice, image, video, text, etc.) and different implementation solutions (group management, status presentation, etc. As shown in 7-4, the IP of the communication network reflects the status of IMS in the network.

 

Figure 7-4: IMS position in the Communication Network

 

IMS is designed for real-time, end-to-end mobile businesses and implements these end-to-end communication services through some key technologies, including: session negotiation and management, QoS Management, and mobility management. Currently, multimedia services that can be implemented on IMS Based on the SIP Protocol include:

(1) interactive services, such as interactive end-to-end games.

(2) multimedia communication services, such as video sharing, terminal content and file sharing, and IMS-based one-click (POC.

(3) Information services, such as voice information, instant messaging (IM), and image chat.

(4) network convergence services, including communications between mobile phones and PCs and fixed telephones.

 

The inherent features of the standardized solution make IMs a reusable business platform that provides basic components and functional components required by most new businesses, this service meets registration, session creation, security, billing, network management, and other basic functional requirements. It is worth noting that IMS has "Access independence". It not only supports 3G Mobile Network/GPRS access, but also supports WiMax and WLAN Access. When the POC service is implemented based on the IMS network, the IMS network uses various call session control functions (cscf, call session control function) and the vested user server (HSS, home subscriber server) the implementation of SIP-based registration (scscf implementation), SIP-based authentication (S-CSCF implementation and HSS cooperation), and SIP routing functions (each cscf, and HSS cooperation ).

 

To implement IMS, carriers need to implement a communication network architecture that supports IMS. A typical IMS communication network system 7-5 is shown.

 

Figure 7-5: A typical IMS communication network system

 

Once the operator has an IMS network and supports brew on the client, it can implement more value-added mobile services. For example, VoIP, instant messaging, video calls, PTT services, and Multimedia conferences. The implementation framework of IMS on mobile phones is 7-6.

The system structure of IMS on mobile phones can be fully implemented through brew. Figure 7-7 describes the brew-based IMS implementation. Through brew's extended applications and underlying services, various protocol stacks can be implemented. The IMS framework includes core IMS functions and enhanced service functions, as well as various application programming interfaces (APIS ), finally, brew is used to implement rich IMS-based applications.

 

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