IMS(IP Multimedia Subsystem)

concept
IMS(IP Multimedia Subsystem),Is put forward by Lucent's next generation of network (NGN) to implement the fusion scheme of network architecture, the bell LABS in IMS key fields of innovation - industry things strengthen layers of various patent technology, determines the Lucent IMS fusion solution of sophistication. IMS solutions relative to the soft exchange solutions has very many advantages in NGN market is occupied an increasingly important role. By 2003, international authoritative standard organization generally IMS as NGN network integration, and business and technological innovation of core standards. For large-scale commercial deployment is concerned, IMS from technology itself has mature enough. Not only realize the initial IMS VoIP business, more important is IMS will more effectively of network resources, user resources and the application resources management, improve the network of intelligent, users can across various network and use a wide variety of end, feel the fusion of communication experience. IMS as a communication architecture, creating a new telecom business model, and expanded the entire information sector development space. In North America five telecoms operator, now we have four deployed lucent IMS technology, for wireless and cable of fusion is extremely important symbolic significance, marks the IMS in global deployment into a new stage. Of course the technology system growth still focus on basic telecom services, achieve a global network unity there is a lot more to change places.

IP in Subsystem

Basic information

IMS, namely IP Subsystem, essentially say in a network structure. The technology is rooted in mobile field, was initially 3GPP for mobile network defined, and in the framework of NGN, IMS should also support fixed access and mobile access. At present the enhancement 3GPPR6 covering IMS has basically been frozen, this symbolized IMS technology have maturity.

In the framework of NGN, terminal and access network is various, and its core network only one IMS, its core characteristics is to adopt the SIP protocol and access irrelevance.

Conform to the trend of IP network, IMS SIP protocol system USES for end-to-end call control. IP technology on the Internet application has been very mature, is the leading technology, Internet and it convenient to provide various information service flexibly, and can according to customer's need to quickly create new services. But one of the most prominent IP technology feature is "do our best", in the security of data transmission and billing control, but ragged and only consider fixed the access method. The traditional based on circuit-switched mobile network, albeit with access flexibility, can be done anywhere and anytime speech exchange but unable to support IP technology, so can form a vertical business spread way, different business application interoperability lower, and need more business gateway access mobile communication network. Different business separately business access, networking and operation control and business applications, including business billing and other major network unit also must establish independent operation system. So, until now telecommunication business mainstream is still voice business. New business deployment, in the present condition is very easy to incur greater risks and costs. In this case, whether YiDongWang or fixed nets are based on IP network to evolution, has become an inevitable trend.

However will IP technology is introduced into the telecommunication level field, we must consider the actual network operators to operators of demand, need IMS network from the nets yuan function, interface protocols, QoS and safety, billing aspects of support fixed the access method. From the current research look, SIP is with simplicity, compatibility, modular design and the third party control based on Internet communications market to become the mainstream of the agreement. So the IMS framework based on SIP through maximum reuse Internet technologies and protocols, inheritance of cellular mobile communication system characteristic of network technology and fully absorb the soft exchange network technology, which can provide the QoS guarantee, telecommunication level of business and effective flexible billing, and have the fusion of network integrated business powerful ability. So, using IMS system, telecom operators can low cost to enter the yearning already a long time of mobile field, but mobile operators can be in ensuring its original voice and text message service quality is not affected, under the precondition of relaxed introducing new rich multimedia services, the so-called whole business operations.

As for the access of irrelevance, it is to point to an IMS reference soft exchange network technology, based on the gateway to communication solutions, including signaling gateway (SGW), media gateways (MGW), media gateway controllers (MGCF) nets yuan and in MGCF and MGW also USES IETF and itu-t T together to develop of h. 248 / MEGACO agreement. This design makes the IMS system of terminal may be mobile terminal, also can be fixed telephone terminal, multimedia terminal, PC machine etc, access is not limited to cellular rf interface can be is wireless of WLAN, or of a wired lans, DSL techniques. In addition, because IMS in business floor adopts the soft exchange network open business provides frame, can fully support based on application server third-party service provision, which means operators may not changing the existing network structure, not devote any equipment cost conditions, easily develop new business, and applied the upgrade.