IP Multimedia Subsystem Research Articles

Security Analysis and Delay Evaluation for SIP - Based Mobile Mass Examination System

IP Multimedia Subsystem (IMS) is considered to be one of the important features in Mobile Next Generation Networks (MNGN). It adds value to the mobile services and applications by integrating mobile network resources, such as location, billing and authentication. This is achieved by enabling a third party access to network resources. In previous work [1] we have presented a testbed to be used as platform for testing mobile application prior to actual deployment. We have chosen a novel IMS based MObile Mass EXamination (MOMEX) system to showcase the benefit of designing an IMS based mobile application. We identify two aspects essential to of the application namely security threats and delay analysis. In this paper we identify MOMEX security threats and suggest strategies to mitigate system vulnerabilities. We then evaluate the performance of MOMEX system in terms of delay and security threats and vulnerabilities. The results presented show system performance limitation and tradeoffs.

A Set-top Box with Virtual Platform Support for QoS Management in IMS Based Multiple Provider Networks

Set-top Box (STB) has evolved from being a device just sitting on top of a TV shelf to a device providing a gateway to the Internet for a home network, receiving services from multiple content providers, and enabling and ensuring Quality of Service (QoS) for the streaming media. IP Multimedia Subsystem (IMS), with its promise to provide a converged access network for multimedia service delivery (such as Triple play & Quadruple play services), has to guarantee QoS support. To enable QoS in IMS-based networks, we have designed a set-top box which provides feedback to the service provider to ensure end-to-end QoS. Our set-top box is designed to provide virtual platforms such that it can support multiple service providers. Each service provider is able to manage its own multimedia streams and ensures the desired network performance for each flow. The set-top box also works as a Home Gateway and provides end-to-end QoS support to the client nodes.

Utilizing the IP Multimedia Subsystem to create an extensible service-oriented architecture

Smart Spaces provide very promising means of creating context-aware environments. Unfortunately, a lack of information about users within Smart Spaces limits their usefulness. We propose a novel solution that involves integrating Smart Spaces with social networks through the IP Multimedia Subsystem. to create truly context-aware and adaptive spaces. By utilizing the wealth of user information present within social networks, smarter and more adaptive spaces can be created. We therefore propose the design and implementation of “SocioSpace” a Smart Spaces framework that utilizes the social context. We design and implement all components of SocioSpace, including the central server, the location management system, social network interfacing components, service delivery server and user agents. We then run various scenarios to test the reliability of the system. The results show the effectiveness of our framework in successfully creating Smart Spaces that can truly utilize social networks to deliver adaptive services that enhance the users’ experiences and make the environment more beneficial to them.

A Fast IMS Service Recovery Mechanism for the Handover Over MIH-Capable Heterogeneous Networks

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.

An IMS Architecture and Algorithm Proposal with QoS Parameters for Flexible Convergent Services with Dynamic Requirements

Quality of Service (QoS) provisioning is one of the main requirements in the 3GPP IP Multimedia Subsystem (IMS) and it has been addressed in different works since the beginning of the IMS standardization process. As a result of the fixed and mobile networks evolution, the parameters standardized in IMS have changed constantly until the specification of the Policy and Charging Control (PCC) architecture that integrates IMS QoS and charging functionalities. However, current IMS QoS specifications still have some limitations to handle service flexibility that is required to provide Internet services over IMS. In this work, we propose an enhanced IMS QoS architecture to support efficient QoS providing for flexible services with dynamic requirements. This proposal is compared against different approaches to evaluate their behavior under network saturation conditions. Simulations results show that the architecture we propose achieves efficiency and flexibility, maintaining the number of blocked and active sessions, and increasing the number of high priority sessions activated in a saturated network.

IMS-Based Centralized Service Continuity

The IP Multimedia Subsystem (IMS) has been selected as a telecommunication industrial standard for the signal processing in the heterogeneous access networks. It is also brought up to handle the mobility management. However, the mobility of the user equipment (UE) may disrupt or even intermittently disconnect an ongoing real-time session, which heavily affects the satisfaction of the users. Therefore, how to reduce the service disruption time gets more and more important. This paper first proposes a centralized service continuity scheme, abbreviated as CSC, in IMS-based networks. The CSC treats handover as a service in the IMS network. Its architecture and operation are based on service invocation. The service continuity procedure is performed by an application server called CSC AS. The CSC AS can carry out the third-party call control for fast session re-establishment by initiating two INVITE requests concurrently. In addition, a variant of the CSC, denoted by CSC*, is derived by adopting the E-IMS AKA with one-pass authentication for achieving the acceleration of IMS registration during the handover. Analytical results show that both schemes could shorten the handover latency significantly, as compared with the standard IMS-based service continuity.

The Session Initiation Protocol (SIP): An Evolutionary Study

The Session Initiation Protocol (SIP) was devel- oped to control multi-media sessions on the Internet. Shortly after its debut as a standard in 1999, SIP was adopted by the 3rd Generation Partnership Project (3GPP) as the preferred signaling protocol for the Internet Multimedia Subsystem (IMS). This adoption provided a boost to the nascent protocol as traditional telecommunication services were interpreted in the context of the new protocol and as SIP introduced richer services in the form of instant messaging and rich presence to traditional telephony. In this paper, we study the evolution of the protocol from its roots to its use in operational networks today and the issues it faces in such networks. We also provide a glimpse to the continued progression of SIP in Peer-to-Peer (P2P) networks and take a critical look at where SIP has succeeded, and more importantly, where it has failed to meet expectations.

Novel Component-Based Development Model for Sip-Based Mobile Application

Universities and Institutions these days' deals with issues related to with assessment of large number of students. Various evaluation methods have been adopted by examiners in different institutions to examining the ability of an individual, starting from manual means of using paper and pencil to electronic, from oral to written, practical to theoretical and many others. There is a need to expedite the process of examination in order to meet the increasing enrolment of students at the universities and institutes. Sip Based Mass Mobile Examination System (SiBMMES) expedites the examination process by automating various activities in an examination such as exam paper setting, Scheduling and allocating examination time and evaluation (auto-grading for objective questions) etc. SiBMMES uses the IP Multimedia Subsystem (IMS) that is an IP communications framework providing an environment for the rapid development of innovative and reusable services Session Initial Protocol (SIP) is a signalling (request-response) protocol for this architecture and it is used for establishing sessions in an IP network, making it an ideal candidate for supporting terminal mobility in the IMS to deliver the services, with the extended services available in IMS like open APIs, common network services, Quality of Services (QoS) like multiple sessions per call, Push to Talk etc often requiring multiple types of media (including voice, video, pictures, and text). SiBMMES is an effective solution for mass education evaluation using mobile and web technology. In this paper, a novel hybrid component based development (CBD) model is proposed for SiBMMES. A Component based Hybrid Model is selected to the fact that IMS takes the concept of layered architecture one step further by defining a horizontal architecture where service enablers and common functions can be reused for multiple applications.

Design and Implementation of IEEE 1900.4 Architecture Using IMS Functionality

We propose a new cognitive radio network architecture using the IP multimedia subsystem (IMS) functionality. We implement the cognitive radio network entities standardized in IEEE 1900.4 on the IMS that exchanges RAN and terminal context information between the networks and the terminals to make optimum and immediate reconfiguration decisions. In our proposed architecture, RAN context information is obtained from cellular networks which are directly connected to the IMS. The presence management functions of the IMS are applied to exchange those information in a “push” manner, which enables immediate notification of changes in wireless environment. We evaluate the performance of the proposed context information exchange method, by comparing with the cases that adequate and immediate RAN context information is not available. The evaluation results show that the proposed framework gives 10-30% superior performance than the conventional cognitive radio networks.

A Secure Architecture for Nomadic User in IMS Network

The IP multimedia subsystem (IMS) is a basis for a significant new architecture which offers network operators the opportunity to expand their services, by integrating voice and multimedia communications and delivering them into new environments with new purposes. Basically, the IMS is an overlay network on top of IP layer that uses Session Initiation Protocol (SIP) as the primary signaling mechanism. SIP works at the application layer in IP networks. It is thus faced to not only the IP-networks security issues, but also to new issues which are related to the SIP protocol directly. Consequently, using IMS bears several new security challenges. This paper presents the most relevant SIP-related security vulnerabilities and threats, and the implementation and simulation test bed to experiment two versions of the SIP Asterisk software to emphasize these threats. The different security mechanisms that can be deployed to overcome the SIP security issues while putting emphasis the most important ones are discussed. Afterwards, the authors propose adaptable solutions to the SIP threats already identified for a specific service (access information from anywhere) in IMS context. Finally, conclusions are drawn and some perspectives are introduced to improve the security of multimedia applications.

Delivery of Unified Communications over Thin-IMS

This paper describes the architecture, design patterns, and implementation of a Unified Communications Solution (UCS) over a home grown thin implementation of IP Multimedia Subsystem (IMS). This thin-IMS implementation makes use of IMS core components, and can serve as a first step towards migration to full IMS. The unified communications solution offers a rich set of services including duplex VoIP, video conferencing, instant messaging, media sharing, child position tracking, active contacts, and email reading. Subscriber profile is leveraged by a targeted video advertisement preview service as a payment method for calls terminating at landline or mobile networks. Subscribers can also use prepaid service for calls terminating outside of the IP networks. In addition to system and software design patterns, the paper addresses critical deployment issues, such as scalability, NAT traversal, network interconnect, ease of service provisioning and administration, and last but not least, user experience. Finally, the paper contrasts the thin-IMS platform to 3GPP standard IMS release 7 specifications.

The multimedia service session handoff method in heterogeneous wireless networks

The IP Multimedia Subsystem (IMS) can provide multimedia services between heterogeneous wireless networks. But the efficiency of the service session handoff will bring a significant impact to user experience. For the integration of heterogeneous wireless networks, we propose a Session Initiation Protocol (SIP) based multimedia service session handoff method named MS²HM. To reduce the handoff delay between heterogeneous wireless networks, the MS²HM uses the methods of advance registration and old-new address temporary matching. We modelled the node processing delay and network transmission delay, and analyse the total delay and the packet loss rate of the MS²HM. Specially, this paper contrastively analyses the handoff delay under different frame error control in the 3G-WLAN integrated network, and the result shows that MS²HM has lower handoff delay than the method proposed by Wedlund and Schulzrinne. The MS²HM can meet the low delay and low packet loss rate requirements of IMS service session handoff between heterogeneous wireless networks, and ensure the QoS of the IMS services.

Conferencing Service Interworking in Peer-to-Peer and IMS Networks

The growth of Internet technologies and the widespread use of mobile devices have been paving the way for the increasing use of conferencing services. Two types of systems have been designed to provide conferencing services: 1) a conferencing system using session control over a peer-to-peer (P2P) network and 2) an IP Multimedia Subsystem (IMS) conferencing system. The IMS conferencing system was developed to adapt to a server-based centralized system, whereas the benefits of the P2P operational model in providing such conference services are widely acknowledged. However, each system provides conferencing services only to its own users. Therefore, in this paper, we propose an interworking model to support multimedia conferencing service between the P2P environment and IMS networks. We also introduce protocol architecture and some service scenarios. To verify this system model and the design architecture, we perform an actual implementation and show experienced test results.

WiMAX-UMTS Converging Architecture with IMS Signalling Analysis to Achieve QoS

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 IEEE 802.16 worldwide interoperability for microwave access (WiMAX) promises to provide high data rate broadband wireless access services. The IP Multimedia Subsystem (IMS) seems to be the technology that will prevail in Next Generation Networks (NGN s), since the interworking environment and the service flexibility that this technology offers to the currently deployed wireless broadband technologies makes it appealing to users, service developers and network operators. In this paper we propose a heterogeneous network model based on the IMS that integrates the Worldwide Interoperability for Microwave Access (WiMAX), Universal Mobile Telecommunications System (UMTS) and provides guaranteed QoS. In this paper, hybrid interworking architecture to integrate 3G (UMTS) and WiMAX networks with QoS is proposed. Moreover, IMS based signaling along with QoS algorithm was analyzed for UMTS and WiMAX interworking Architectures. QoS parameters such as Ethernet load and delay, IP Packet end to end delay, TCP delay, Active TCP connection count and TCP retransmission count, Email download response and upload response, Voice jitter, Voice packet delay variations and voice traffic received were analyzed.

Extending emergency services coverage in cooperative IMS networks

There are various emergency services based on the wireless sensor network technologies being proposed recently. However, the ability of these services/networks is inherently limited by geographical restrictions and need to be deployed in advance. This paper proposes an application level approach to enhance the service coverage and availability of emergency services. Specifically, we augment these services with All-IP network infrastructure based on IP Multimedia Subsystem (IMS). Furthermore, we integrate the IMS Emergency Services architecture with Cooperative Network technology to provide ubiquitous emergency services. We also investigate the prime problems of cooperation between heterogeneous networks and IMS. Finally, we present and discuss the experimental results of performance in our Cooperative Emergency IMS testbed.

Advanced Path-Migration Mechanism for Enhancing Signaling Efficiency in IP Multimedia Subsystem

Since Internet Protocol (IP) is the most important protocol in Next Generation Networks (NGNs), 3rd Generation Partnership Project (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, in IMS, the media traffic and signaling are delivered through IP transport. The media traffic may affect the signaling efficiency in core network, due to traffic collisions and best effort packets delivery. This paper proposes a novel path-migration mechanism for enhancing the traffic efficiency in integrated NGN-IMS. The simulation results show that the interference and traffic collision can be reduce by applying proposed path-migration mechanism and the signaling efficiency in core network can be improved with higher system capability and voice quality.

Decentralised secure handover in IMS-based networks

This paper proposes a decentralised secure handover scheme for service continuity in IP Multimedia Subsystem (IMS)-based networks: Decentralised Service Continuity (DSC). The novelty of the DSC is that the Proxy Call and Session Control Function (P-CSCF) in IMS is enhanced as a distributed Application Server (AS) with third-party call control (3PCC) for handling the handover. Moreover, the DSC integrates a secure context transfer mechanism to the P-CSCF to get the context information of a newly attached User Equipment (UE) and guarantee the confidentiality and the integrity. The DSC could shorten the IMS transmission latency significantly and reduce UE power consumption, as compared with the standard IMS-based service continuity and the Mid-Session Macro-Mobility (MSM).

IMS-based Fast Session Handover with Available Network Resources Discovery of Access Networks

The rapid spread of smart phones causes the explosion of media traffic. This encourages mobile network operators (MNOs) to coordinate multiple access networks. For such an MNO, the IP Multimedia Subsystem (IMS) is a promising service control infrastructure to ensure a QoS guaranteed communication path for the media in the multi-access network. IMS-based service continuity enables user equipments (UEs) to continuously use IMS-based services (e.g., VoIP) even when the UEs make handovers between different access networks where the UE is assigned the different IP address, respectively. In the case where the UE cannot simultaneously use multiple wireless devices, there is the possibility of a long media disruption time during handovers. This is caused by several consecutive handovers as a result of attempting to discover the access network where the UE can have the QoS-guaranteed communications. In this paper, we propose a method for reducing the media disruption time when the UE makes handovers between different access networks. In the proposal, the UE proactively performs the service continuity procedure, and selects an access network that can provide the required network resources to the UE. We implement and evaluate the proposed method, and show how the media disruption time can be reduced.

Advances on Adaptive Systems in NGN

This paper provides the state of art and hints on how to lay the foundations of an adaptive QoS approach in Next Generation Networks (NGN). The key idea is to provide a model, which would offer one application version or another, depending on the Quality of Service (QoS) negotiated at the session establishment in a NGN. The stake of this research is a better-balanced usage of the network, for maximizing the service offered to the user given his or her network capacities. It encompasses the model for such an implementation in a NGN as IP Multimedia Subsystem (IMS).

Taking initiative in market creation – a business ecosystem actor perspective

The purpose of this paper is to examine the role of taking initiative in developing next generation communication services. Focusing on different actors in our analysis, we adopt a business ecosystem perspective, where the role of network effects and interoperability are seen as prerequisites for market creation. In order to create new markets, however, certain actors need to take the initiative and subsequent risks. We provide an exploratory case study on IP multimedia subsystem (IMS) technology, which shows that taking initiative by different actors differ significantly in various phases of the development of new communication offerings. Thus, it is important to recognise that there is not only a need for a hub firm to lead the development as a whole, but more likely there is a need for several actors taking the initiative in the right time and at the right place.