Research On IMS Technology And The Exploration In Jilin Telecom Realization

With the rapid development of telecommunication technology, people's needs on the communication are more diversified. The contact between people by the letter first, and then development to playing fixed telephone. As mobile phones appear, mobile communication gradually began to become the main way of modern communications. Making phone calls and sending text message also become the most basic needs as the communication technology constantly update. People begin to pursue the more convenient and high-end communication services. Surfing online, chatting with QQ, getting e-mail, watching video online something like these things which originally need sitting in office or home to finish can complete already with the hands of 3G phones while traveling. The arrival of the era of 3G can greatly satisfy people's growing demands of cell phone office and entertainment function. But, telecommunication industry did not stop technology update steps because of satisfying the people's current demands.The introduction of IMS made the telecommunication technology developing to a higher level. It fused the fixed network and mobile network successfully, and fused the communication network with the internet successfully. It really becomes a collect variety of functions and business extremely inclusive network. The inclusive of IMS doomed its powerful functions, and also bound to become a new technology of each operator pursuit. Jilin telecom as one of three operators of Jilin province will provide users with the most high-quality service. This paper will introduce the IMS and compares with the soft exchange, and make the practice exploration of IMS network transformation of Jilin province.The first chapter mainly introduces the definition of IMS and the development of international organization standards. The international standards organization mainly includes 3GPP, 3GPP2, TISPAN, ITU-T, which study IMS systematic from the different points. In general, the IMS network at abroad has perfect but we are study it in-depth at home. Anyhow, IMS as a more mature of the next generation of fusion network technology has been widely applied to each big operator has become an inevitable trend in the development of telecommunication industry.The second chapter basically introduces the soft exchange and IMS network comparison. This chapter introduced the soft exchange first. Fixed network fail in trap due to the limitations of traditional PSTN network. Since 2002, the major domestic operators at home start thinking the problems of transition in future. Mainly ponder questions including: how transform from narrowband communication to broadband communication, how transform from voice service provider to a provider which provide comprehensive information including content services, how transform from single business operator to full service operator. The transformation of telecom operators include service transformation, business transformation, network transformation, technical transformation, management transformation and cultural transformation etc. It's an arduous and complicated system engineering. The transform basic of telecom operators is network transformation. PSTN has failed to meet business innovation and provide comprehensive information service requirement. It must transform to the next generation network which based on IP, and also introduces the soft exchange technology. The soft exchange function mainly in the following aspects: call control and processing functions; business provides and exchange function; interchange function; resource management functions; billing function; address analytical, routing and authentication function right discrimination. In the field of mobile telecom, it also experiencing the similar history from circuit switching to packet switching. With the GSM and CDMA (IS-95) mass popularization, communication environment has changed greatly. Mobile communication also transforms from simple speech to broadband business direction such as data, multimedia, mobile internet and so on. But the telecom operators need to establish a traditional solution of network to each business, which caused many business network coexistence situations. The traditional telephone exchange technology and business realization ways cannot meet the need of application. So the fusion of mobile telecommunication and internet is needed. IMS arises at the historic moment. As the key component of 3G system, it makes users can use the cellular mobile system access to get all business provided by internet. IMS features: IMS based on SIP session control; IMS has access irrelevance; IMS fully absorb the soft exchange technology; Support packet domain business roaming; User data centralized management; Unified authentication; Provide dynamic and abundant combination business. The architecture of IMS network are mainly divided into: business application layer, session control layer and the access layer. The function entity consisted by Session control layer including attribution user server, signing location function SLF, call session control function CSCF, multimedia recourse function MRF. Based on the introduction of soft exchange and IMS network, the compare between IMS network and soft exchange has made.This paper focuses on the third chapter, the exploration of IMS network in Jilin telecom implementation. Currently Jilin telecom mobile core network is based on soft exchange, fixed network are upgraded to the soft exchange network. Based on the status quo, Jilin telecom network core nets transform to IMS needs three stages. The first stage is the soft exchange network and IMS coexist period. During this period, the soft exchange network continue carrying most users, part of users who want to experience new IMS business are placed in HSS which is part of IMS. The communication between IMS network and soft exchange realized by MGCF. The second phase simplified communication period between two nets. The fixed-line and C nets comprehensive terminal innings MGCF function. And the hardware and software can smooth MSCe innings upgrade to support MGCF function. MGW software and hardware can be smooth upgrade to IM-MGW. This will simplify the IMS and soft switching between each other, lower resources occupation of voice delay and transmission. The third stage is the IMS and soft exchange fusion period. The soft exchange network degenerate into a access network, an IMS-CMN can degenerate into SIP-Proxy, facilitate room routing among each SIP server. The service control layer of network is IMS Core (S-CSCF), CS and IMS achieving a fully fusion. MGCF and IMMGW can be used to interchange specially between nets. After completing the merge of mobile soft exchange and IMS network, other networks can gradually intervention IMS network through transforming. Once Jilin telecom built an IMS network through upgrading exist network, it would have the following characteristics: facing the whole business operation; unified authentication; unified session control; unified business trigger; unified business platform; supporting multiple access; supporting multiple terminal type; supporting multiple types of fusion application; operational and manageable; realizing unified net management using the exist network management; realizing unified business accepting and pricing through now nets BOSS system. IMS is the core of the IMS network architecture nets. The communication between IMS and other network is mainly through MGCF and IM-MGW. The IMS core network's communication can realized through special IP. All access network access IMS network through SBC and AGCF, AGCG just responsible for old fixed-line terminal access, support SIP fixed-line terminal can directly through the SBC access. CSCF meta-nets achieve business unification trigger, and PSS/AS application servers provide uniform business platform. The docking between IMS network and exist operational support telecom network through the centralized network management equipment, toll-collection devices and the business accepting interface machine to realize unified net management, unified pricing and unified business management. New SIP AS for IMS users provide broadband to media business. Exist nets SCP upgrade support based on ISC interface of SIP to dock with IMS or through SSF meta-nets to realize the docking between exist nets and SCP INAP/CAP agreement by communication continue to provide users with narrowband service. Through the unified HSS for the users to provider a uniform intelligent business starts. Business layer mainly composed by application servers and resource servers, which provide various business (such as games, meetings, instant messaging) and business ability (Presence, group etc.). Operation support layer mainly provides network management, signing data storage, billing, Web Portal unified operation, addressing and so on. Session control layer mainly complete registration, rights appraisal, session path control, business trigger, topology hidden, routing, resource control, communication and other functions. Access & interchange layer provider QoS resources control, which also provides the fixed-line access location management and network access allocation function, complete NAT control functions, complete IMS network and PSTN/PLMN/NGN/h.323 network communication. IMS meta-nets gathering according to area first and then gathering on CE again. The signaling and media information of IMS network bearded by NGN VPN, and NGN MGNT VPN bearing IMS nets webmasters/billing/business issuing information. Each of IMS meta-nets veneer working in the main standby mode. Signaling plane and the reliability of support network plane by VRRP guarantee. Media plane directly connected telecom router. Using VRRP realize MRFP reliability. Using BFD+IPFRR realize IM-MGW reliability. BAC working in all the proxy pattern and enable port polymerization beside the way by hanging. Through a pair of switch by gathering across the board after the link polymerization TRUNK connected to two routers respectively. There are more GE bound TRUNK are needed by access side and media.