IP multimedia subsystems in 3GPP and 3GPP2: overview and scalability issues

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.

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 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.

Internet protocol multimedia subsystem (IMS) is an overlaid infrastructure above the packet-switched domain of the universal mobile telecommunication system core network. IMS enables and enhances real-time multimedia mobile services. IMS signaling and media are separated in IMS. For media session negotiation, two basic procedures in IMS are (i) IMS registration procedure and (ii) IMS incoming call setup procedure. IMS signaling needs to traverse a set of call session control functions (CSCFs), which are proxy-CSCF, interrogating-CSCF (I-CSCF) and serving-CSCF (S-CSCF). However, we observe that I-CSCFs need to query the home subscriber server (HSS) to obtain the name of S-CSCF for each subscriber's request in both the basic procedures. It results in a certain load occuring in the HSS and a certain procedure delay also occurs. Therefore, we employ the distributed hash table (DHT) into IMS to form a DHT-based I-CSCF network. Each I-CSCF in the DHT-based I-CSCF network can share and relieve HSS's load. As a result, the incoming call setup procedure can be speeded up. We also propose two maintaining procedures to maintain the DHT-based I-CSCF network for I-CSCFs join and leave scenarios. We propose one maintaining mechanism to guarantee the proposed system to be able to work well in the failure scenario of I-CSCF. According to the performance evaluation results, the load of HSS is reduced and shared among I-CSCFs in the home network and the signaling delay cost of the incoming call setup procedure is less than that of existent systems even if failure occurs and then is removed.

IP Multimedia Subsystem (IMS) as the core of Next Generation Network (NGN), its security is vital important. However, IMS is a network with openarchitecture based on IP, which brings a lot of security issues. There has already some research results about IMS security, but systematic and model-based research results are lacked. Based on TVRA method, this paper establishes a comprehensive vulnerability analysis model of IMS network, and makes a systematic analysis about the security objectives, assets, weaknesses, threats and other attributes of IMS network by using this model. The research results of this paper can provide the basis for the security assessment of IMS network.

Today, Ukraine is actively working to implement 4G and 4.5G technologies on networks of mobile operators. However, due to inaccuracies in forecasting the development trends of this type of networks, a situation has arisen whereby 2G and 3G networks will be used to service all voice traffic for a long time. As the research results show, one of the necessary conditions for the normal functioning of networks of mobile operators is the introduction of IP Multimedia Subsystem (IMS) as the main element of the management level. One of the main requirements for the IMS system is the requirement for the reliability of its operation. Since the requirements for reliability are very high, their fulfillment is impossible without the use of reservation methods. Therefore, the paper discusses possible reservation methods for the IMS system. The main elements of the IMS system were determined, models for assessing the reliability of operation with various reservation methods were developed, and a comparative assessment was made.

An IP multimedia subsystem (IMS) has been specified to provide multimedia services in 3GPP release5. In IP multimedia subsystem, both packet-switch domain and IMS authentications are necessary for the IMS subscriber. The IMS authentication is carried out by IMS authentication and key agreement (AKA). It is inefficient that there are so many steps in IMS AKA. Hence, this paper proposes an improved IMS AKA procedure, which can not only guarantee system security but also improve system performance.

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.

As third-generation (mobile) networks (3G networks) become a commercial reality, strong movements are emerging in the direction of a common infrastructure based on the Internet protocol (IP). The users' mobile devices are like another IP host connected to the Internet. In such a scenario, the network operator infrastructure is degraded to bit pipes. To avoid this, the 3G partnership project (3GPP) and ETSI TISPAN have designed IP multimedia subsystem (IMS), a service platform that aims to place the network operator again in the central role of service provisioning. In this article we examine IMS from a mobile operator's perspective and analyse its possible adaptation to the next-generation networks

The third-generation partnership project (3GPP) and 3GPP2 have standardized the IP multimedia subsystem (IMS) to provide ubiquitous and access network-independent IP-based services for next-generation networks via merging cellular networks and the Internet. The application layer Session Initiation Protocol (SIP), standardized by 3GPP and 3GPP2 for IMS, is responsible for IMS session establishment, management, and transformation. The IEEE 802.16 worldwide interoperability for microwave access (WiMax) promises to provide high data rate broadband wireless access services. In this paper, we propose two novel interworking architectures to integrate WiMax and third-generation (3G) networks. Moreover, we analyze the SIP-based IMS registration and session setup signaling delay for 3G and WiMax networks with specific reference to their interworking architectures. Finally, we explore the effects of different WiMax-3G interworking architectures on the IMS registration and session setup signaling delay.

4G systems have been continuously evolving to cope with the emerging challenges of human-centric and machine-to- machine (M2M) applications. Research has also now started on 5G systems. Scenarios have been proposed and initial requirements derived. 4G and beyond systems are expected to easily deliver a wide range of human-centric and M2M applications and services in a scalable, elastic, and cost efficient manner. The 3GPP IP multimedia subsystem (IMS) was standardized as the service delivery platform for 3G networks. Unfortunately, it does not meet several requirements for provisioning applications and services in 4G and beyond systems. However, cloudifying it will certainly pave the way for its use as a service delivery platform for 4G and beyond. This article presents a critical overview of the architectures proposed so far for cloudifying the IMS. There are two classes of approaches; the first focuses on the whole IMS system, and the second deals with specific IMS entities. Research directions are also discussed. IMS granularity and a PaaS for the development and management of IMS functional entities are the two key directions we currently foresee.

The IP Multimedia Subsystem (IMS) is an access-independent, IP based service control architecture. Although, the security and data privacy aspects are very important in the IMS global objectives, they attract little attention so far. Secure access to multimedia services is based on SIP and HTTP digest on top of IMS architecture. Authentication is only based on SIP and is directly coupled to the SIP registration procedure. The third Generation Partnership Project (3GPP) provided Generic Bootstrapping Architecture (GBA) to authenticate the subscriber before accessing multimedia services over HTTP however through a heavy process. In this paper, we propose a new IMS Service Authentication scheme using Identity Based cryptography (IBC). Our solution enhances the security of the IMS authentication process and is promising in enabling new social services since it is based on the user's identity (which could be mapped to his presence). We analyzed the security of our new protocol and we began the evaluation of its performance. We obtained a better security as well as a performance gain compared to the classical service authentication approach in IMS.

Users and enterprise needs will drive multimedia service evolution for both mobile and fixed operators. IMS (IP Multimedia Subsystem) is a recognized standard of 3GPP group. IMS is well integrated with existing voice and data networks, while adopting many of their key characteristics. The SIP servers are the key part of the IMS structure. They are the main components responsible for processing and routing messages. With communication networks getting more and more present in our daily activities, network outages or significant degradations of the quality of service (QoS) become less and less tolerable. Our research works on improvement of the QoS in IMS networks. It is base in the one hand modeling traffic and on the other hand dimensioning traffic. These performance optimizations are essentially dedicated to the traffic of input and output flows at SIP servers. We build OpenSource IMS platform under UBUNTU Linux distribution.

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.