New Joint Dual Mobile Service Discovery-Exposure Model using Bipartite Graph

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.

In the signaling plane of an IMS (IP Multimedia Subsystem) network, the interrogating Call/Session Control Function (I-CSCF) is required to choose the serving CSCF (S-CSCF) for user requests arriving at the proxy CSCFs (P-CSCF). This requires S-CSCF selection in such a way that the response time is minimized. However, in an overloaded situation, the P-CSCF entry points for arriving requests must balance between rejecting new requests and having an acceptable response time from S-CSCF for those that are allowed to enter. In this setting, we consider a number of controls for congestion avoidance that work in conjunction with S-CSCF selection in an IMS Network. For balancing between rejection of requests and the response time, we also propose a composite metric. Through our studies on grid topologies, we observe that one of the avoidance algorithms, the bang-bang control, generally shows to be the most promising toward striking a good balance between rejection of requests and the response time.

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.

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.

The IP Multimedia Subsystem (IMS) has been considered to be exclusive to big players of the telecommunication world. Session Initiation Protocol (SIP) has been standardized by IETF and solutions based on it have been in the market at least for a decade. It is also an essential part of the IMS, as it is the control protocol of IMS. Recent development of the Linux platform and the Open source IMS system has lead to a situation where the IMS is also an affordable solution for smaller telecommunication companies. The obvious question has been whether the level of performance with Open source IMS is really suitable for business usage. ETSI-TISPAN has unified IMS performance measurements by defining a common framework which to follow in measurements. The paper presents comparisons between IMS and SIP based networks in call and messaging performance. the Open IMS solution by the Fraunhover Focus Institute is compared with the OpenSIPS, an open source SIP server. The number of users in our measurements was chosen to be 100 000, a large enough number to be considered as a suitable number of users for small or moderate business usage needs. Our study shows that both of the systems are able to handle this many users and, in the case of OpenSIPS, with a clear margin. It was also discovered that both systems are reliable and are suitable for small and moderate business usage.

BT has commenced the switch-over to its 21st Century Network — an all-IP based network which will reduce costs and provide a more ‘innovation-friendly’ platform where exciting new services can be rolled out much more quickly and cost effectively. Increasing computing power and openness on the client device coupled with the move to an IP environment fundamentally alters the competitive landscape for service provision, making it much harder to control the customer’s service experience. Further complexity is introduced by convergence — the requirement for services to run across a multitude of networks and devices. The challenge is to create an infrastructure capable of delivering the exciting new own-build and third-party converged services users want while preserving ease of use and security. The IP multimedia subsystem (IMS) element of the 21CN architecture is a key enabler in reaching these goals. Alcatel-Lucent is a vendor with a strong track-record both in supplying IMS products and in ongoing research activities, considering improvements and extensions to the current IMS standards. This paper summarises activities to date in a research collaboration between BT and Alcatel-Lucent which is looking at the area of improved intelligence in the provision of converged services over an IMS architecture. The collaboration utilises capabilities produced by Alcatel-Lucent’s research department called the Reachability Server to implement a number of novel converged service scenarios. The paper introduces the Reachability Server, describes the collaboration, summarises the scenario implementation work completed to date and presents a number of conclusions and observations.

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.

Distributed intrusion detection scheme for next generation networks

To support user mobility across different devices, communication session continuity should be enabled at session initiation and during a session. The session continuity can be managed by either a user or dedicated network nodes such as back-to-back user agent (B2BUA) in IP Multimedia Subsystem (IMS) architecture. When network manages the session continuity, user experience is enriched because users do not need to know how to perform session transfer. However, in IMS architecture, three different network nodes (SIP forking proxy, SIP registrar and B2BUA) need to cooperate for session continuity. When single user (callee) logs in from different devices, it is very hard to achieve cooperation. In addition, these network nodes should be scalable when many users request this service simultaneously. This paper proposes a general architecture that supports the user mobility and how the general architecture can be realized into a Web-based communication system. Our initial analytical result shows that the usage of computing resources (e.g. CPU) is reduced while supporting scalability, thanks to the simple Web client service infrastructure and Web Socket connections on top of HTTP.

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.

IP Multimedia Subsystem (IMS) is the main solution for new generation networks providing multiple services proposed by third generation partnership project (3GPP). IMS architecture is based on several protocols guaranteeing connection and data transmission. Among these protocols, Session Initiation protocol (SIP), which is regarded as the main IMS signalisation protocol, hence considered a target for several attacks. To secure this protocol, 3GPP proposed an authentication and key agreement protocol called IMS-AKA. However, this protocol suffers from weaknesses in terms of complexity and user identity protection. In this work, we are particularly interested in IMS- AKA+ protocol, an improved version of IMS-AKA. This work aims to analyse performances of IMS-AKA+ against IMS-AKA using simulation and AVISPA specification. Results showed that IMS-AKA+ outperforms IMS-AKA resisting to many security attacks such as Spoofing attacks, SPIT and Dos-Synchronization. In addition to this, we propose an initial approach toward securing media plane by introducing a shared key at the end of IMS-AKA+ process using Secure Real Time protocol (SRTP).

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.

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.

In mobile networks, hand over refers to the process of transferring a communication from one cell to another considering the power levels of the signal and latency values. In LTE (Long Term Evolution), base stations are able to perform handover by using the X2 interconnected interface. To provide voice call over LTE (VoLTE) using a packet-switch network, an IMS (IP Multimedia Subsystem) network is also deployed. The main contribution of this work is the analysis of power consumption of a Device under Test (DuT) during intra-cell handover procedures for a VoLTE call. Empirical results show the energy consumption along the different stages of the communication between the DuT and the base station. In addition, jitter and throughput values are assessed during the intra-cell handover process. The highest power consumption was obtained during the hand over procedures and as expected, jitter values increase too. Empirical results provide key points for energy efficiency improvements.

The IP Multimedia Subsystem (IMS) is a converged framework for delivering voice, video and data communication services to mobile and fixed users. The present operator-centric IMS model, which assume a single operator for the access network, IMS core and application servers, restricts if and how users can access services beyond the IMS core network. The present IMS model, by limiting the subscribers' choice might be rejected by many end users. User-centric service provisioning should establish the users' control and thus commence the customer interest for IMS. In this paper, we study the problems that a user-centric IMS architecture should address, and broaden the scope of our previously designed, third-party service enabled IMS model [21] by showing its use in user-centric service provisioning. Third-party offered service subscription and session setup procedures are explained with two use cases. The Users' profile management and privacy endurance, possible terminal implications are also discussed in the context of a user-centric IMS model.