The Research On Ip Multimedia System QOS Scheme Of Next Generation Network

The IP Multimedia Subsystem or IP Multimedia Core Network Subsystem (IMS) is an architectural framework for delivering Internet Protocol (IP) multimedia services. It was originally designed by the wireless standards body 3rd Generation Partnership Project (3GPP), as a part of the vision for evolving mobile networks beyond GSM. Its original formulation (3GPP Rel-5) represented an approach to delivering "Internet services" over GPRS. This vision was later updated by 3GPP, 3GPP2 and ETSI TISPAN by requiring support of networks other than GPRS, such as Wireless LAN, CDMA2000 and fixed line.To ease the integration with the Internet, IMS uses IETF protocols wherever possible, e.g. Session Initiation Protocol (SIP). According to the 3GPP, IMS is not intended to standardize applications but rather to aid the access of multimedia and voice applications from wireless and wireline terminals, i.e. create a form of fixed-mobile convergence (FMC). This is done by having a horizontal control layer that isolates the access network from the service layer. From a logical architecture perspective, services need not have their own control functions, as the control layer is a common horizontal layer. However in implementation this does not necessarily map into greater reduced cost and complexity.Alternative and overlapping technologies for access and provisioning of services across wired and wireless networks include combinations of Generic Access Network, soft switches and "naked" SIP.Along with the rapid growing use of the multimedia services ,the aded requirements of the quality can not be fulfilled by the traditional "best efort" IP service which is subject to unpredictable delays and loss.The tremendous changes in network technology has brought challenges to build a new network management system and also to IMS-based next generation network service quality (QoS) management, So how to guarantee the QoS (quality of service) in IMS becomes a curial problem.This thesis is to address QoS problem of IMS in next generation network.The thesis introduces the IMS system, combined with the general principles and QoS technologies. The thesis also analysis of the building next-generation IMS-based network QoS management system in the background. Then, according to IMS features and services, the basic requirements of quality management, in-depth study of the IMS management layer, network layer and transport layer QoS control mechanism for implementation, and detailed analysis of policy-based QoS management, Diffserv model and SIP signaling QoS, on this basis, proposed a policy-based E2E QoS mechanism.