IP Multimedia Subsystem Research Articles

IMS 네트워크 기반 이종 다중 AS 환경에서의 부하 분산 기법

In this paper we propose a load balancing scheme for heterogeneous multiple AS's (Application Server) in IMS (IP Multimedia Subsystem) based network. In IMS network, to perform load balancing among multiple ASs with different registration pattern, different weight value should be set for each AS. In previous systems, there exists an inconvenience that the weight value should be set manually by the operator after monitoring the result. In this paper we propose a method to calculate optimal weight in automatic manner and to perform load balancing simultaneously. We also propose a simplified algorithm to reduce calculation in specific situation and present a way to apply our proposed scheme in adaptive manner according to the situation. Through simulation result, we verify that our proposing scheme outperforms previous schemes in load balancing and adjusts well to the change of the system in automatic manner with fast convergence.

Scalable multimedia delivery with QoS management in pervasive computing environment

People are increasingly demanding rich-media and bundled services. However, the diverse terminals, heterogeneous networks as well as various user requirements constrain the multimedia access to low quality in the pervasive computing environment. In order to enable rich-media delivery across a wide range of devices and networks, multimedia adaptation with scalable QoS management is an important issue. Our research introduces a Scalable Multimedia Delivery (SMD) framework with QoS management. This framework utilizes the CAM4Home metadata model to aggregate multimodal rich media services into a bundle. MPEG-21 metadata is integrated into the CAM4Home model to enforce interoperable QoS management. The issues in supporting QoS are addressed on both fidelity and modality. We further develop the SMD system in IP Multimedia Subsystem (IMS) architecture, where multimedia adaptation is implemented through application-level QoS negotiation.

Transaction-Pattern-Based Anomaly Detection Algorithm for IP Multimedia Subsystem

The Internet Protocol (IP) multimedia subsystem (IMS) plays an important role when migrating to next-generation networks. Based on the all-IP network architecture, at least an IP address is assigned to user equipment for communication. It thus brings not only value-added services, but also security issues such as attacks and threats from traditional IP networks. This paper proposes a novel scheme to detect the anomaly attempts or attacks in an IMS core network. Our proposed scheme adopts the support vector machines (SVMs) technique as our data-mining module. We also utilize the high-order Markov kernel to enhance the detection and prediction rate in sequence calls. Furthermore, the detection algorithm and feature selection for SVM kernel are designed by utilizing IMS transaction patterns. It is proved that the proposed algorithm can efficiently filter out the anomaly attempts in an IMS core network.

Intelligent connection manager for seamless interworking of multi-technology mobile devices

As wireless service providers ramp up their Long Term Evolution (LTE) installations, and telecommunications and cable operators continue to expand Wi-Fi coverage, 100 percent wireless coverage with overlapping areas of 3G, 4G, and Wi-Fi access is becoming a reality. Ensuring that a multi-mode device can roam across different radio access technologies while maintaining seamless session and service continuity across virtual private network (VPN), Voice over Internet Protocol (VoIP), and streaming video applications is critical. Differences in 3GPP, 3GPP2, and WiMAX standards led to the absence of uniform interworking solutions. Specific interworking standards per access technology pair define the behavior and interfaces for common core network components including the IP anchor, AAA, and HSS, as well as the IP Multimedia Subsystem (IMS). This paper discusses the Intelligent Wireless Connection Manager (IWCM), a critical component of a mobile device platform that enables seamless and transparent inter technology mobility for user applications through IP session continuity, make-before-break handoff algorithms, and uniform quality of service (QoS) and policy management APIs.

Session Initiation Protocol firewall for the IP Multimedia Subsystem core

As the deployment of Session Initiation Protocol (SIP) accelerates, there is an accompanying need to secure the SIP infrastructure. One way to do so is through a SIP firewall, which is loosely defined as a device that blocks attacks mounted via SIP. Using this definition, a firewall is indistinguishable from a session border controller (SBC), also used by SIP service providers to secure their networks. SIP firewalls and SBCs are often deployed by SIP service providers at the periphery of the network to impose some manner of order on the SIP traffic before allowing it to enter the network. In this vein, a SIP firewall needs to effectively block many SIP attacks and distinguish a distributed denial of service (DDoS) attack from a classic overload traffic arrival rate. But what exactly is a firewall and what features should it provide in its role of inspecting SIP traffic bound for the service provider's network? What are the economic and technical tradeoffs necessary for ubiquitous deployment? In this paper, we define the role of a firewall in protecting the IP Multimedia Subsystem (IMS) or SIP-based core network, distinguish it from an SBC, and characterize the specific threats to SIP messages at the L2 (data link layer), L3 (network layer), L4 (transport layer), and L5 (session layer). We show how a SIP firewall can thwart these attacks and we propose an implementation based on a simplified, but fully hardware accelerated SIP proxy as a front end SIP firewall. Such a system naturally blocks most attacks and implements many defense mechanisms.

TRIM: An architecture for transparent IMS-based mobility

In recent years, the development and deployment of new wired and wireless access network technologies have made the ubiquitous Internet a reality. Users can access anywhere and anytime to the broad set of value-added Internet services, which are delivered by means of the IP protocol. In this context, 3GPP is currently developing the IP Multimedia Subsystem (IMS), as a key element that allows to evolve from the ubiquitous access to the Internet services towards a next generation network model, by providing a set of essential facilities such as session control, QoS, charging and service integration. Nevertheless, several open issues still need consideration before the future Internet becomes real, such as supporting user mobility in IP networks. Although mobility support in the Internet is receiving much attention, IMS networks present inherent particularities that require further analysis. The solutions proposed so far for IMS do not support mobility transparently to the end-user applications, or address the problem by introducing complex changes to the IMS infrastructure. This paper presents TRIM, an architecture for transparent IMS-based mobility. TRIM supports mobility in IMS networks transparently to the end-user applications, which are unaware of the handover management procedures executed between the mobile node and the network. We have performed several experiments with a TRIM prototype, using a real IMS testbed with 3G and WLAN access networks, validating the proposal for UDP and TCP based applications.

IMS Security Analysis using Multi-attribute Model

IP Multimedia Subsystem (IMS) plays as a core platform in next-generation-network architecture, which advocates for an open and inter-operable service infrastructure. However, over the years, not much attention has been paid to the security problem of IMS. The time has come to now address security issues. This paper proposes a multi-attribute stereo model based on X.805 standard, which addresses a comprehensive, top-down, end-to-end perspective for IMS security analysis, classification and assessment. Besides, a detailed threat analysis of IMS is demonstrated and the vulnerability utilized by the threat is also presented.

IMS emergency services: a preliminary study

Emergency call and walkie-talkie are two services utilized in emergency situations. During Typhoon Morakot in 2009, we experienced the deficiency of emergency call service that cannot continuously track callers in real time and walkie-talkie communications where a speaker may not be granted the permission to talk. These issues can be resolved by the emergency call and push-to-talk over cellular services in IP Multimedia Subsystem. This article conducts a preliminary study on how these two services can be effectively exercised in IMS.

A token-bucket based notification traffic control mechanism for IMS presence service

Presence is a service that allows a user to be informed about the specified state of another user. Presence service has become a key enabler for next-generation applications such as instant messaging, push-to-talk and web2.0. However, recent studies show that the notification traffic of presence service causes heavy signaling load on IP multimedia subsystem (IMS) network. This paper introduced a token-bucket based notification traffic control (TNTC) mechanism, which is an application layer solution deployed at the presence server. The TNTC aims at upgrading valid access probability while controlling the notification traffic. A mathematical model of a queuing system is proposed to describe TNTC. We analyzed its main probability features and investigated the effects of different parameters on the performance of TNTC. Extensive simulations verified that TNTC can effectively control notification traffic and perform better than the existing schemes in terms of valid access probability and update arrival rate.

Seamless Lawful Interception Handover for 3G IP Multimedia Subsystem (IMS)

After the 9.11 terror attack, lawful Interception (LI) has emerged as an important tool for anti-terrorist activity. Law enforcement agents and administrative government bodies effectively monitor suspicious target users of permanent IP-based network devices by LI in Packet Data Networks (PDNs). However, it is difficult to perform LI in monitoring migrating users from a location to another, who change their IPs due to the proliferation of portable Internet devices enabling 3G IP Multimedia Subsystems (IMS). The existing, manual handover technique in 3G IMS makes it even more difficult to continue the LI activities due to time-lag reissuance of LI authority warrants when the target users move to a new LI jurisdiction via a roaming service. Our proposed model is a seamless LI handover mechanism in 3G IMS to support mobility detection of the target users. The LI warrants are transferred to the new LI agent automatically with the target users when they move to a new LI jurisdiction. Thus, time-lag human intervention of reissuance of the LI warrants is removed and enables the LI authorities to continue monitoring. In the simulation of our proposed mechanism, the quality of lawful interception achieves a mean score of over 97.5% out of the possible 100% maximum score, whereas the quality of the existing mechanism has a mean score of 22.725%.

IMS management and monitoring with eTOM framework and composite web service

The IP multimedia subsystem (IMS) is an architectural framework for delivering multimedia in IP network. However, the IMS is less clear regarding the monitoring of performance and fault management; beside the new generation operations systems and software (NGOSS) system manipulate QoS based assurance scenarios with enhanced telecom operations map (eTOM), which describe all management operations for system level monitoring and management (SLM&M), but this specification is generic. In this article, we propose a design of SLM&M, which integrates new technologies in network management, such as WSOA for communication and data processing as business processes; and BPEL to orchestrate the monitoring operation. The first scenario of SLM&M is to monitor supply scenario of multimedia service in IMS network, which is necessary to collect management information. This information leads to the SLM&M to monitor the network behaviour after delivery. In this work, we examine the response time in information collection operation during supply.

The IMS-based mobile monitoring system for integrated networks

The IP multimedia subsystem (IMS) is able to deliver the multimedia messages through different types of networks, and alleviate the message losing in the single or fixed line network. With IMS supported, many applications can be integrated in the seamless networking environment, so that users can access the network applications anytime and at anywhere. In this paper, we will introduce an on-line monitoring system with IMS platform for integrated networks. The proposal is able to associate with many value-added services, and users can access the services in the easy and convenience way. By the comparisons to other systems, our proposal not only is easily to use and deploy, but also provides most functions.

Improved IP Multimedia Subsystem authentication mechanism for 3G-WLAN networks

The provision of IP Multimedia Subsystem (IMS) introduces important advantages for users of 3G-WLAN networks. However, a multi-pass authentication procedure needs to be performed before accessing the IMS, resulting in added overhead and possible Quality of Service (QoS) degradations. The problem is further compounded when the user moves from one Wireless Local Area Network (WLAN) domain into another, which requires the authentication procedure to be repeated. To mitigate this problem, we present a lightweight, robust, and architecture-compatible IMS authentication protocol that implements a one-pass IMS procedure by promoting efficient key re-use for a mobile user. The security of the proposed protocols is verified using the Automated Validation of Internet Security Protocols and Applications (AVISPA) security analyser. We also analyse the authentication delay of our proposed scheme. Numerical results reveal a reduction in user authentication delay of more than 50% compared to the existing authentication procedure.

A context-aware service architecture for the integration of body sensor networks and social networks through the IP multimedia subsystem

In this article a new context-aware architecture is proposed for the integration of body sensor networks and social networks through the IP Multimedia Subsystem. Its motivating application scenarios are described. The benefits and main research challenges for an efficient communication using the proposed architecture are outlined.

Future convergent telecommunications services: creation, context, P2P, QoS, and charging [Guest Editorial

his series is an attempt to provide a holistic view of telecommunications services (having covered previously both enterprise [1] and residential [2] segments). The current issue is the second part of the New Converged Telecommunications Applications for the End User feature topic. In the previous issue ([3]), two published articles described services that rely on IP Multimedia Subsystem (IMS) infrastructure (which is progressively being deployed by telcos), related to lookup services and vehicular technology. In this second part a total of eight articles complete the selection of material fulfilling the call for papers' intention of providing an update and new insights into the applications and services a converged world is bringing, concentrating on application-only topics in the field of services for mass market users.

Proposal of a Next Generation Network Architecture Based on Web Service Technologies

The IP Multimedia Subsystem (IMS) establishes a session between end terminals as a client/server application in the Next Generation Network (NGN). These days, many application services are being provided as Web services. In this letter, we propose a new NGN architecture conforming to the architectural styles of Representational State Transfer (REST), which is a Web service technology for solving interoperability and traffic concentration problems in the Session Initiation Protocol (SIP).

An ontology-based context inference service for mobile applications in next-generation networks

Context enabled mobile applications are considered to provide a richer experience and to enhance the user interaction by acquiring information that allows the identification of the user's current situation. Modern context inference infrastructures can source, process and deliver user information. However, a commercialization towards a context service has still been prohibited by the need for global service coverage and accurate context identification. With the advent of Next Generation Networks, telecom operators can leverage All-IP networks to design external service interfaces that integrate a diverse set of sources and context inference processes that are easily scalable, extendable, and robust at the same time. This article presents a telecom operator service that supplies mobile applications with context information to illustrate how context infrastructures can leverage NGN capabilities. The article introduces an innovative context inference approach involving third Party applications within the inference process itself. This is done by structuring the ontology context model in layers of complexity and inferring particular context information via modules, which are designed in collaboration with third party developers. Furthermore, the service is compliant with state-of-the-art IP Multimedia Subsystem infrastructures and provides an interface that uses HTTP/SOAP and HTTP/REST communication as well as the Session Initiation Protocol of the IMS. A first proof of concept indicates an increased service adoption, a higher accuracy of context, and an increased robustness towards errors.

Control-level call differentiation in IMS-based 3G core networks

The 3GPP-defined IP Multimedia Subsystem is becoming the de facto standard for IP-based multimedia communication services. It consists of an overlay control and service layer that is deployed on top of IP-based mobile and fixed networks, in order to enable the seamless provisioning of IP multimedia services to 3G users. Service differentiation, which implies the network's ability to distinguish between different classes of traffic (or service) and provide each class with the appropriate treatment, is an important aspect that is considered in 3G networks. In this article, we present a critical review of existing service differentiation solutions and propose a new control-level call differentiation solution for IMS-based 3G core networks. The solution consists of a novel call differentiation scheme, enabling the definition of various categories of calls with different QoS profiles. To enable the support of such profiles, an extended IMS architecture, relying on two adaptive resource management mechanisms, is proposed. Furthermore, simulations are used to evaluate the system performance. Compared to existing service differentiation solutions, our solution offers several benefits, such as: flexible QoS negotiation mechanisms, control over many communication aspects as means for differentiation, and a dynamic and adaptive resource management strategy.

Load balancing mechanism of service control server cluster in IMS-based IPTV

IMS-based IPTV not only requires higher performance of Service Control Function ( SCF) server, but also brings many restrictions to the traditional load balancing technologies due to a Session Initiation Protocol ( SIP) with double integrity requirements of transaction and dialog. Combining service trigger mechanism in IP Multimedia Subsystem ( IMS) and the session statistical characteristic of the IPTV services, a multi-level load balancing mechanism with the features of service differentiation among clusters and server-load awareness within every cluster was discussed to solve the performance bottleneck in IPTV SCF, and a method differentiating SIP transaction priorities and a lightly random scheduling algorithm based on a dynamic weight were proposed. Finally, the technological feasibility was verified in IPTV prototype, and the detailed solution was depicted.

Huawei's leadership role in IMS standards development and in its own proprietary Softswitch

Purpose – The purpose of this paper is to provide a case study of Huawei's leadership role in the Internet Protocol Multi‐media Subsystem (IMS) international standards effort while it developed its own proprietary Softswitch solution. This strategy of leading the standards bodies, developing proprietary standards, and being the low‐cost provider is helping Huawei to become the number one telecom company in the world.Design/methodology/approach – For this case study over 20 industry experts, both outside of Huawei and within were interviewed, and web resources utilized. The big challenge was the nebulous name IMS which combined technical standards with a vision for the future of the telecommunications.Findings – It is a common assumption that China is a copier of technology and not one of the world's leaders in terms of technical innovation. China's Huawei Technologies Company Ltd (Huawei Jishu Youxian Gongsi) is rapidly becoming one of the world's largest telecom manufacturers and one of the key innovator...