User-centric service provisioning for IMS

Within the 3rd Generation Partnership Project (3GPP), the thrust of the session initiation protocol (SIP)-based Internet protocol (IP) multimedia subsystem (IMS) is envisaged to allow a swift progression towards the provision of multimedia applications for increasingly demanding end users. The paradigm of service programmability using open network application programming interfaces (APIs), with open service access (OSA) as its main exponent, is helping to drive this development together with the use of SIP. The focal point of this paper will be the multimedia services architecture in the IMS by providing details of the interaction of the IMS and the application servers in the form of the OSA gateway and the SIP application server. The paper aims to assess the value of the IMS service control (ISC) interface on application server interaction in the IMS. The paper will provide an OSA application use case, and will also present the presence server as an example of a SIP application server that fits in with the IMS. © 2003 Lucent Technologies Inc.

The main stages of the historical development of telecommunication networks are shown. It is noted that today the most common concepts are NGN (Next Generation Network), supporting the functionality of Triple-Play Services (triple services – voice, video and data transmission), as well as IMS (IP Multimedia Subsystem), which combines cellular technology and landline communications. They are able to provide a wide range of services: basic, additional, intelligent. In addition, IMS is able to provide mobile services. The IMS architecture layers are presented – transport layer, control layer; layer of service and application servers. Particular attention is paid to the layer of service and application servers. Based on the analysis of ITU recommendations, the main telecommunication services quality indexes are determined, namely, the time of service provision, the length of the queue that the service request falls into to wait for service on the server, and the probability of refusing to provide services. Based on the proposed mathematical models of the NGN intelligent superstructure, analytical expressions are presented for calculating the quality indexes of intelligent services in NGN for one type of service and for K types of services, taking into account the self-similarity of traffic, and without taking into account. To evaluate the quality of services in IMS, it is proposed to use the approaches of queuing theory and tensor analysis. Tensor analysis offers a mathematical apparatus for transforming coordinate systems, considering IMS as a set of geometric objects whose projections are different in different coordinate systems, but the physical properties of the objects themselves do not change. Expressions are proposed that make it possible to calculate the following QoS indexes in IMS: average queue length, average residence time of an application in the system for all types of services in IMS. It is considered that the incoming traffic is the simplest. Further development of the work is to take into account the self-similar nature of traffic, which is created by the flow of requests for services that come to IMS, as well as the limitations of the server buffer, which will allow a more accurate assessment of the quality of services in IMS.

As the next generation network NGN core network solution, IMS (IP multimedia subsystem) can support a variety of terminal access method and provide a foundation for the fixed network and mobile network integration. IMS is using the session initiation protocol (SIP) as its core control protocol to establish, manage and terminate multimedia services. IMS provides multimedia communication services based on data, voice and video, it gives users an unprecedented experience. Satellite mobile communication system has become an integral part of the global communication network. It can be seamlessly connected to the global communication network, which provides a strong complement to the ground network coverage. In recent years, the research and implementation of multimedia services through satellite access to the IMS core network has also been concerned. However, the problem of propagation delay of satellite channel has a great influence on the QoS (quality of service) of IMS access. Therefore, the application of IMS streaming media transmission and SIP signaling interaction must also consider the propagation delay of the satellite channel. In this paper, the process of satellite access to IMS and the transmission delay of satellite communication was simulated; the complete IMS voice and video service access and communication process was designed and implemented. In order to solve the problem of the propagation delay of the satellite in the communication process, the session signaling process was optimized.

This chapter describes the support for IP based multimedia services on Third Generation (3G) wireless cellular networks. While earlier cellular networks offered only basic IP connectivity on a best-effort basis, 3G networks provide explicit support for real time multimedia services with guaranteed Quality of Service (QoS). As a result, they can offer traditional voice telephony, rich telephony services and multimedia streaming over IP, both inside a 3G network and in conjunction with external networks such as the Internet, the Public Switched Telephone Network (PSTN) and the Integrated Services Digital Network (ISDN). In fact, 3G networks will deploy for the first time in a large scale technologies such as IP version 6 (IPv6) and policy based IP QoS, spearheading the introduction of such technologies into the Internet. The two most important aspects of 3G networks with respect to IP based multimedia services are the IP Multimedia Subsystem (IMS) and the Multimedia Broadcast / Multicast Service (MBMS). The IMS enables complex IP based multimedia sessions to be created with guaranteed QoS for each media component. Example applications include voice telephony and video conferencing. The IMS interoperates with both traditional telephony services and external IP based multimedia services. The MBMS provides native IP broadcast and multicast support in 3G networks, allowing high bandwidth services to be economically offered to multiple users. Example applications include video streaming via multicast and location based services via broadcast. The MBMS interoperates directly with IP multicasting. While both the IMS and the MBMS are IP based, their standardization is proceeding independently. It is however clear that their combination would allow numerous new services to be provided. The outline of this chapter is as follows. In Section II we give an overview of cellular networks and their evolution, while in Section III we describe in detail a specific 3G network, the Universal Mobile Telecommunications System (UMTS). Section IV presents an introductory description of the features and services provided by the IMS and the MBMS. In Section V we provide the details of the IMS, including service architecture, session setup and control and interworking issues. Section VI describes the MBMS in the same manner as for the IMS. Finally, Section VII discusses the QoS issues for IP based multimedia services, describing the overall QoS concept, the policy based QoS control scheme and its application to IMS sessions. At the end of the chapter, Tables II and III list the acronyms used. An extensive UMTS vocabulary is provided in [1].

The 3 GPP IP multimedia subsystem (IMS) is currently expected to provide the basic architecture framework for the next generation network which will bridge the traditional divide between circuit-switched and packet-switched networks and consolidate both sides into one single network for all services. Therefore, the imminent commercial roll-out of IMS will have immense impact on the whole way future mobile business applications are designed, developed and deployed. This paper presents a survey about the application-oriented research project CAMPARI (configuration, architecture, migration, performance analysis and requirements of 3G IMS) which aims at inves-tigating a "minimal-optimal" IMS configuration with respect to architecture and quality-of-service aspects. After a brief survey of the IMS core components, we introduce our OpenSER-based IMS prototype implementation and present the "IMS in a bottle " approach. Based on our practical experiences with this testbed system, we finally discuss important current and future challenges including migration, interworking, charging, identity management, security, and regulatory aspects.

IP multimedia subsystem (IMS) is the core multimedia network in the next generation all-IP environment. It provides access independence for multimedia applications across fixed and mobile access networks. When a roaming IMS subscriber connects to IMS through mobile access networks, handover becomes a critical issue; this needs to be addressed. Since IMS concerns application layer handover for session mobility, the application layer handover takes a long time for recovering the suspended sessions according to the standard IMS session reestablishment procedure. This introduces noticeable service interruption to end users and cannot be tolerated for real-time applications. In this paper we propose a fast IMS service recovery mechanism to shorten the service recovery latency by combining the IEEE 802.21 Media Independent Handover service and the IRTF Media-Independent Pre-Authentication frameworks. The proposed mechanism performs the necessary IMS registration and QoS re-negotiation procedures in advance of lower-layer handover. Thus it reduces the service recovery latency for suspended services. With parallel design in time, the proposed mechanism is able to shorten overall handover relevant latency as well. Technical examination shows that it is easy to deploy the proposed mechanism in current multimedia service environments.

4G wireless communication expects to integrate different radio access technologies together to meet wide expectation from users and to support mobility. Call Admission Control (CAC) plays important role in such heterogeneous environment to effectively utilize network resources and to meet user QoS. This paper proposes IP Multimedia Subsystem (IMS) based integrated architecture for UMTS-WiMAX-WLAN overlay networks and Traffic Aware Dynamic Speed Sensitive CAC (TADSS-CAC) for these integrated heterogeneous networks. IMS architecture was designed by 3rd Generation partnership project (3GPP) and its main goal is to provide seamless multimedia connectivity between 3GPP standard and non 3GPP standard networks. In this paper IMS entity is used for interworking 3GPP based UMTS and non 3GPP based WiMAX and WLAN. Existing Speed Sensitive CAC (SS-CAC) preferably admits high velocity users to high coverage area network and low velocity users to low coverage area network that avoids unnecessary handoff and signaling overhead caused by high velocity user admitted to low coverage network. SS-CAC not considers specific network feature and traffic type for admitting calls. The Proposed TADSS-CAC preferably admits high velocity users either to WiMAX or UMTS (high Coverage networks) based on service type and low velocity or static users to WLAN except voice service. TADSS-CAC preferably admits low bandwidth loss tolerant delay sensitive services (eg., voice) to UMTS and huge bandwidth QoS restricted services (eg., video streaming, video conferencing) to WiMAX. TADSS-CAC also provides dynamic bandwidth reservation for handoff calls based on traffic condition that decreases packet loss, delay and increases network throughput. The proposed TADSS-CAC is applied for loose, tight, hybrid coupled UMTS-WiMAX-WLAN networks and performances are compared with existing SS-CAC.

Although the IP Multimedia Subsystem (IMS) and Web Serviceshave been developed on the basis of different Service Delivery Platforms (SDP), opportunities for new services have emerged from converged access to IMS and Web Services. Researchers are focusing on finding means to develop converged access architectures for IMS and Web Services while preserving the benefits they provide and not overburdening the end users' terminals. In this paper, we classify the existing converged access methods for IMSand Web Services into four categories, compare them and identify their drawbacks. To address these drawbacks, we have designed a hybrid thin client-based novel architecture for converged access to multimedia services provided by a combination of IMS and Web Services. The proposed solution limits the impact of platform heterogeneity and resources by relinquishing the complexity of signalling and session management to an intermediate virtualization server, which in turn acts as a client for network-based services.

IP Multimedia Subsystem (IMS) is a novel architecture, which is the basis for the new network architecture for future mobile applications incorporating voice, video and many other multimedia services. It is also the ultimate goal for the development of ALL-IP network, which is supported and developed by China Mobile many other famous operators all over the world. IMS is an overlay network on top of IP that utilizes SIP (Session Initiation Protocol) as the primary signaling mechanism. Because of its IP based architecture, IMS faces many new security challenges both in core network layer and application layer. Therefore, this paper provides an overview of the IMS architecture and presents some researches and discussions on the relevant security challenges.

The evolving standards of mobile communications, the wide variety of services they offer and the rapid growth of the Internet have made a merger of the two network technologies inevitable. One of the most prominent platforms that has been developed to facilitate this is the IP Multimedia Subsystem (IMS) concept. Many mobile communications standards integrate IMS as the main core network architecture and Quality of Service (QoS) is the main concern for customer satisfaction. A major approach to optimisation of QoS is the Differentiated Services scheme, and a simulation study of implementations of this is presented. The study covered an IMS core network architecture modelled with discrete-event network simulator software, with a Differentiated Services QoS scheme run over it with differing bearer traffic scenarios. Implications for core network architectures are discussed.

As a result of the evolution of computer and networking technologies, the third generation partnership project (3GPP) has proposed the IP multimedia subsystem (IMS) as a key element in the UMTS architecture supporting multimedia services in the packet switched domain. Extending the IMS with support for location based services (LBS) enables enhanced services and offer new revenues to the system. Connecting the IMS core network with a real positioning system providing support for LBS is an open issue. This paper addresses this issue and presents the design and implementation of an IMS location server (ILS) connecting the IMS with a positioning system. From the IMS perspective, ILS serves as a service enabler for LBS in the mentioned subsystem. In order to demonstrate proof-of-concept in enhancing IMS-based services, a location-aware push-to-talk (LaPoC) prototype service has been developed. The service has been integrated with the Ericsson mobile positioning system (MPS). This paper also gives the results of performance measurements including traffic load analysis and session establishment time.

A linear chained approach for service invocation in IP Multimedia Subsystem

Todaypsilas user wants exciting new services at reduced costs. Legacy ldquovoicerdquo services are considered to be bare minimum. To satisfy their customers and be competitive, Telecom service providers are pressured to provide converged and differentiated services at reduced cost. IP multimedia subsystem (IMS) is touted to be next generation telecom architecture that enables service providers to achieve this requirement. IMS architecture allows service providers to offer a variety of multimedia services in the service layer. Service providers today are building an eco-system with partner vendors to offer new services in this layer. With the success of person-to-person and person-to-content services in the Internet world, it becomes more compelling for mobile device manufactures and service providers to reach out to developer community to create more innovative applications with IMS infrastructure. This paper describes how ldquoservice creationrdquo focus is being shifted from operators and mobile device vendors to third party developers. It explores the benefits of having a service creation platform to aid in developing such services. It outlines the elements of software development kit (SDK) which will help in maximizing productivity and enables developers to focus on creativity. This paper analyzes the need for a complete simulated setup for developers to create and test their services before deploying into real network. There are different service creation environments that are available like service delivery platforms (SDP), JAIN SLEE, and OSA/Parlay etc. In this paper the primary discussion is on the usage of standards based API in IMS/SIP SDK. It dwells more into JSR API for client development and application server development. It also touches upon how SIP SDK can be interfaced with Web 2.0 components.

The 3 rd Generation Partnership Project (3GPP)'s UMTS networks promise to deliver an abundance of advanced, innovative, and feature-rich applications to end-users in a 3 rd Generation (3G) wireless environment. An IP Multimedia core network Subsystem is being introduced as part of this 3G wireless environment which aims to enable the convergence of, and access to, voice, video, messaging, data and web-based technologies for the wireless user. The goal is to combine the growth of the Internet with the growth in mobile communications. The service control architecture for the IMS can be summarised as consisting of an Application Server, providing the execution environment for the applications, and communicating with the Call State Control Function that handles the session control and mobility management functionality. Three general sets of standardised platforms for service control are being introduced in the UMTS' IMS, each one addressing particular needs, from legacy service support to light weight SIP based support. This paper aims to provide an overview of the IMS service control architecture focusing on the rational of the decisions taken in 3GPP.

A key advantage of the IP Multimedia Subsystem (IMS) is that it promotes the development of innovative multimedia services designed to bring an enhanced experience to the end user. The presenceand availability service is viewed as an indispensable feature for these next-generation services to help service providers generate new revenue and reduce churn. Numerous new services are currently being designed to take advantage of this feature. In this paper, we examine presence and availability in the context of IMS and describe its architecture as defined by the 3rd Generation Partnership Project/3rd Generation Partnership Project 2 (3GPP/3GPP2) and the Internet Engineering Task Force (IETF). In addition, we provide an analysis of presence updates and propose a user model and a traffic model to quantify the signaling traffic that such a feature can generate on a network. Through this model, network designers can examine the processing requirements for presence servers and other IMS components (i.e., call session control function [CSCF]) as well as the cost of transporting such traffic in the network.