The IMS service platform: a solution for next-generation network operators to be more than bit pipes

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].

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.

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.

IP Multimedia Subsystem (IMS) network peering is a key enabler that will help accelerate deployment of next-generation IMS-based networks. Today's early deployments of dispersed IMS networks require public switched telephone network (PSTN)/public land mobile network (PLMN) bridges for network interconnection between IMS islands. The PSTN/PLMN bridging arrangement is inefficient, however, in that it results in unnecessary settlements for the carriers. It further impedes the implementation of rich multimedia and Voice over IP (VoIP)-related services that require end-to-end Internet Protocol (IP) connectivity. Last, it perpetuates the reliance on the existing PSTN/PLMN network for voice calls among subscribers served by different IMS-based carriers. This paper analyzes in detail the IMS peering challenges from the perspective of Session Initiation Protocol (SIP) signaling peering. It discusses issues related to the routing of SIP messages, and addressing, address resolution, and discovery of peering points for IMS signaling peering. It further establishes that a new routing algorithm is needed that will allow signaling peering points to dynamically discover the “best” transit network among others for reaching a destination. In closing, it presents a high-level IMS signaling routing process that includes, among other benefits, support for number portability as a key function for inter-carrier IMS peering.

With the advent of 5G technology, the enhanced Mobile Broadband technology is translating 5G-based Internet of Things (IoT) such as smart home/building into reality. With such advances, security must mitigate greater risks associated with faster and more accessible technology. The 5G-based IoT security analysis is crucial to IoT Technology, which will eventually expand extensively into massive machine-type communications and Ultra-Reliable Low Latency Communications. This paper analyses the countermeasures and verification methods of eavesdropping vulnerabilities within IoT devices that use the current 5G Non-Standalone (NSA) network system. The network hierarchical structure of 5G-based IoT was evaluated for vulnerability analysis, performed separately for 5G Access Stratum (AS), Non-Access Stratum (NAS), and Internet Protocol (IP) Multimedia Subsystem (IMS). AS keystream reuse, NAS null-ciphering, and IMS IPsec off vulnerabilities were tested on mobile carrier networks to validate it on the 5G NSA network as well. A countermeasure against each vulnerability was presented, and our Intrusion Detection System based on these countermeasures successfully detected the presented controlled attacks.

IMS (IP multimedia subsystem) is a main trend of development NGN. The base of IMS is an Internet Protocol which initially did not provide support for quality of service. However, for the transmission of multimedia streams is necessary to ensure a given level of quality of service (QoS). Therefore, IMS QoS estimation is a necessary task but a high complexity of network topologies and a large number of information flows makes it difficult to solve this problem. In IMS network, QoS support is provided by the interaction of systems of IMS on control and application planes. This interaction based on the signalling message exchange that also has delay. This paper presents the results to create a nodal tensor model of IMS network for delay analysis. In this model, the main systems of the IMS network such as CSCF (Call Session Control Function), HSS (Home Subscriber Server) etc. are represented as a single-server queuing systems. Model is formed in accordance to the postulates of the tensor analysis of networks. Moreover, proposed model allow estimating the delay time as for the individual routes, and for the whole network. Research of the model allowed determining such distribution of traffic that resulted to the minimum value of the delay that in turn leads to increased QoS of information flows in an IMS network.

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.

Due to Internet Protocol (IP) is the most important protocol in Next Generation Networks. 3GPP utilizes Session Initial Protocol (SIP) based on IP as the base protocol for negotiating sessions in IP Multimedia Subsystem (IMS). Different from traditional circuit-switched network, the media traffic and signaling are delivered through IP transport layer in IMS. The media traffic may affect the signaling efficiency in core network because the traffic collisions and delivery packets in best effort. This paper proposes a novel path-migration mechanism for enhancing the traffic efficiency in IMS. The simulation results show that by adopting proposed path-migration mechanism, the interference and traffic collision can be reduced and the signaling efficiency in core network can be improved.

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.

Summary form only given. Telecommunication networks are evolving from closed systems with limited, standardized services, to open systems which will allow great creativity in building and deploying new services. These systems will heavily leverage Internet technology in an effort to create this open environment. This evolution is being aggressively pursued by wireless service providers (WSPs). Along with the benefits of these networks come increasingly high risks of a variety of attacks that may compromise security. Current, so called second generation (2G) wireless telecommunication networks are implemented using standardized control protocols for user and device authentication, mobility management, session control and services control. These networks are closed in the sense that control messages are exchanged on a private packet-switched network based on the signaling system No. 7 standards. Because of their closed nature, there are few successful attacks on these networks. The next, so called third generation (3G) wireless telecommunication networks are migrating towards IP technology, with the ultimate goal being an all-IP network. Standards for these systems, called the IP multimedia subsystem (IMS) are being defined by the third generation partnership projects (3GPP and 3GPP2). These networks will use IP for transport of information, and Internet protocols such as the session initiation protocol (SIP) and mobile IP, for session control and mobility management. These networks open the possibility for IP-based services and must interwork with 2G networks. Because new services will be introduced in the IP-domain of these networks, new attacks on 3G networks are possible. Because IP networks are more accessible than SS7 networks, the control portion of the 3G networks is now more vulnerable to attack. These attacks may be remote denial of service attacks, or attacks that target the integrity of specific services. The means of the attack may vary depending on the interworking model used and the service being offered. In this talk we discuss the different security risks in IP-based 3G networks, different attack types, and the trade-offs of high performance, open network architectures versus secure network infrastructure.

Chapter 16 - The IP Multimedia Subsystem: True Converged Communications

The Internet has experienced tremendous expansion in the past several years. Demands for IP multimedia services are emerging. The third-generation (3G) wireless networks aim to support mobile users with numerous Internet services. 3G standards organizations are developing IP multimedia subsystems (IMS) to achieve seamless integration between Internet and 3G networks. Moreover, the collaboration between IETF, 3GPP, and 3GPP2 is essential to the development of IMS for next-generation networks. This article first provides an overview of 3GPP and 3GPP2 IMS and illustrates the IMS requirements, architectures, and functional models. We then discuss potential scalability issues in IMS. This article provides guidance for constructing a robust and scalable IMS.

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) 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.