ZTE's IMS-based Multi-network Convergence Solution Zhang Jian With the continuous tracking of network evolution and many years of accumulated technical advantages, ZTE rolled out ZIMSTM, a complete IMS-based innovative solution supporting the Fixed Mobile Convergence (FMC) and CT-IT convergence. ZIMSTM helps a traditional telecom operator to transform into an integrated communication and information service provider that can deploy a convergent Next Generation Network (NGN). ZIMSTM is an end-to-end solution including terminal, access, core, and service platform. Based on a number of standards like 3GPP, 3GPP2, TISPAN, ITU-T and OMA, ZIMSTM features open architecture, integrated services platform and unified user data management system. It has proven interoperability with various access technologies such as WCDMA, TD-SCDMA, CDMA2000, WLAN/LAN, WiMAX, cable broadband access and xDSL. Moreover, it simplifies service creative environment, enabling powerful service provisioning; it supports flexible network deployment, enabling centralized and distributed network planning; and it is built on the unified all-IP hardware platform to support smooth evolution to NGN, protecting the operators' investment. ZTE's IMS solution leads the industry in quality, interoperability and technology innovation. Flexible system design ZIMSTM is designed with open architecture to provide unified session control and home services to fixed, mobile and other networks with different IP accesses, bringing great convenience to full-service operators while reducing their OPEX. To create IMS-vendor operation environment, ZIMSTM provides standard and open interfaces that ensure smooth interworking with IMS equipment from other vendors. ZTE's IMS-based core network (CN) products have successfully passed IMS interoperability testing at the Global MSF Interoperability (GMI) 2006 event, demonstrating excellent compatibility, flexibility and stability. They support interconnection with different external networks while delivering topology-hiding function to prevent outsiders from knowing about the internal details. ZIMSTM can optimize network resources as required, providing enhanced IP-based QoS management and service-based local control. With advanced network resource reservation capabilities, it can deliver classified services to authorized subscribers. With a highly integrated and flexible design, ZIMSTM can be deployed to meet the actual requirements. For a small-scale application, its Proxy-Call Session Control Function (P-CSCF), Interrogating-CSCF (I-CSCF), Serving-CSCF (S-CSCF) and Breakout Gateway Call Function (BGCF) are integrated; for a middle-scale application, its I-CSCF, S-CSCF and BGCF are co-located while P-CSCF is independently deployed; for a large-scale application, P-CSCF, I-CSCF, S-CSCF and BGCF are all distributed independently. Unified service platform The key of FMC lies in the convergence of the service layer. ZIMSTM provides an integrated service platform (ZXUP10) to support fully converged IMS multimedia application environment. ZXUP10 supports three IMS-based service provision modes: Session Initiation Protocol Application Server (SIP-AS), Open Service Access Application Server (OSA-AS) and CAMEL IP Multimedia Services Switching Function (CAMEL IM-SSF) to facilitate deployment of multimedia services. It has standard and open interfaces, allowing more service and content providers to be introduced in the IMS industry chain; it provides horizontal service structure that supports both ISC and CAMEL protocols, allowing simultaneous service delivery across different networks; it incorporates a flexible charging mechanism that supports time, flow, content and QoS based charging capabilities; it adopts a distributed structure that shares the workload among application servers, avoiding traffic congestion and enhancing system stability. Field-proven applications ZTE started the research and development of IMS strategic products in 2002. As one of the few vendors in the industry that can provide end-to-end solutions, ZTE has developed a complete IMS solution, ZIMSTM, using 3GPP Releases 6,7 and TISPAN NGN Release 1. By focusing on FMC, ZIMSTM provides a graceful solution without any misalignment between fixed and mobile roadmaps. In March 2006, ZTE partnered with China Unicom to trial the IMS FMC network, which is the world's first convergence of WCDMA, CDMA2000 and fixed networks. The strategic cooperation for NGN between ZTE and China Unicom paved the way for active exploration and practice on FMC. At the end of 2006, ZTE was the sole vendor to win an IMS commercial deal from China Mobile. ZTE provided China Mobile with IMS communications services on the unified service platform, bearer network and terminals. The convergence of multiple means of communication such as fixed phone, mobile and PC helps users increase their work efficiency while saving costs. ZTE has also scored victories one after another in the global IMS market. Early in 2006, the company partnered with France Telecom (FT) to develop IMS clients and handsets and was shortlisted in April 2007 for the FT's IMS project. In November 2007, it demonstrated the integration of its innovative IMS products with Telemanagement Forum's (TMF) New Generation Operations Systems and Software (NGOSS) framework as part of the TMF's Catalyst Project. In December 2007, it worked with Orange Poland to successfully launch the first IMS trial based on the EV-DO Rev.A technology. In January 2008, it inked a framework agreement with Libya Telecom & Technology (LTT) to build an end-to-end IMS network based on WiMAX access.