Το αντικείμενο αυτής της διπλωματικής εργασίας είναι η μελέτη της δομής υπηρεσιών πάνω στα 0ίκτυα Επόμενης Γενιάς (Next Generation Networks, NGN). Συγκεκριμένα, περιγράφεται η αρχιτεκτονική IMS (IP Multimedia Subsystem) πάνω στην οποία βασίζεται η δομή των 0ικτύων Επόμενης Γενιάς. Στα πλαίσια της παρούσας διπλωματικής εργασίας γίνεται αρχικά μια σύντομη αναφορά στο ιστορικό δημιουργίας του IMS, ενώ στην συνέχεια γίνεται μια εκτεταμένη περιγραφή του μοντέλου και του τρόπου λειτουργίας του IMS. Συγκεκριμένα, αναλύονται οι οντότητες και τα σημεία αναφοράς από τα οποία αποτελείται το IMS καθώς και τα πρωτόκολλα που χρησιμοποιεί. Στη συνέχεια γίνεται μία αναφορά στην ασφάλεια του IMS, όπου αναφέρονται πιθανοί κίνδυνοι και απειλές για το IMS καθώς και τρόποι αντιμετώπισής τους. Έπειτα, παρουσιάζονται και περιγράφονται αναλυτικά οι υπηρεσίες που μπορεί να προσφέρει το IMS στα πλαίσια των 0ικτύων Επόμενης Γενιάς. Τέλος, γίνεται παρουσίαση ενός παραδείγματος εφαρμογής της υπηρεσίας VoIP πάνω από την IMS αρχιτεκτονική. Για την υλοποίηση αυτού του παραδείγματος χρησιμοποιήθηκε το πρόγραμμα προσομοίωσης OPNET 10.0, ενώ συλλέχθηκαν αποτελέσματα σχετικά με τη συμπεριφορά του πρωτοκόλλου SIP και της υπηρεσίας VoIP σε IMS περιβάλλον. / The objective of this diploma thesis is the study of the service structure of Next Generation Networks (NGN). Especially, the IMS architecture (IP Multimedia Subsystem) is being described, which the NGN structure is based on. Initially, there is a quick reference to the history of the development of IMS, and continually an extensive description is being made about the model and the functional mode of IMS. Next, security aspects of IMS are being described, and continually there is a presentation about the services that IMS offers. Finally, an example is being presented regarding the application of VoIP service using the IMS architecture. For the configuration of this example, the simulation program OPNET 10.0 was used, while results were collected regarding the behavior of SIP protocol and VoIP service in the IMS environment.

The IP Multimedia Subsystem (IMS) is an open IP based service infrastructure that enables an easy deployment of new rich multimedia services mixing voice and data. The IMS is an overlay network on top of IP that uses SIP as the primary signaling mechanism. As an emerging technology, the SIP standard will certainly be the target of Denial of Service (DoS) attacks and consequently IMS will also inherit this problem. The objective of proposed architecture for IMS is to cram the potential attacks and security threats to IP Multimedia Subsystem (IMS) and explore the security solutions developed by 3GPP. This research work incorporates the ideas of immune system and multiagent architecture that is capable of detecting, identifying and recovering from an attack. The proposed architecture protects IMS core components i.e. P-CSCF (Proxy- Call Session Control Function), I-CSCF (Interrogating-Call Session Control Function), S-CSCF (Serving Call Session Control Function) and HSS (Home Subscriber Server) from external and internal threats like eavesdropping, SQL injection and denial-ofservice (DoS) attacks. In the first level i.e. CPU under normal load all incoming and out going messages were investigated to detect and prevent SQL injection. Second level considers Denial of Service (DOS) attacks when CPU load exceeds threshold limit. Proposed architecture is designed and evaluated by using an approach called Architecture Tradeoff Analysis Method (ATAM). The results obtained confirm consistency of the architecture. / kalyani-0046737527800

The diploma thesis deals with open source implementations of IMS technology. The theoretical part describes the functioning of IMS and its architecture, including the protocols used, the process of registration and connection establishment, as well as potential security threats to IMS systems. Two open source IMS projects were selected, Open IMS Core and Project Clearwater, on which the work is focused. In its next part, the diploma thesis deals with the description of selected open source IMS projects, this part also includes a description of the implemented security of both projects and a detailed procedure of system installation with any necessary configuration. In its practical part, the diploma thesis focused on performance testing of selected projects using the Abacus 5000 hardware tester. First, initialization tests were performed, which verified the possibility of communication between the tester and the tested projects. Subsequently, it was possible to perform performance testing of selected projects. In performance testing, emphasis is placed on system stability, performance in the area of call set-up speed and response time of SIP messages and speed of user registration in the network, at different load levels. The systems have been tested for both call set-up and user registration. Part of the testing is also the implementation of the flood DoS inviteflood attack and the system's response to the increasing intensity of the attack. The last chapter is devoted to the comparison of selected IMS projects, where the test results are clearly presented. This chapter is partly based on publicly available information, such as the technical documentation of individual projects and possibly publicly available mailing lists. Part of the diploma thesis is also a laboratory task in which the student tries to work with Open IMS Core. The laboratory task focuses on the process of creating a user and his registration in the IMS network, establishing a call between individual users and internal routing in IMS networks. The task focuses mainly on signaling processes within the implemented tasks.

Ubiquitous Sensor Network (USN) est un réseau conceptuel construit sur des réseaux physiques existantes. Il se sert des données détectées et fournit des services de connaissances à quiconque, n'importe où et à tout moment, et où l'information est générée en utilisant la sensibilité au contexte. Dispositifs et USN portables intelligents émergent rapidement en offrant de nombreux services fiables facilitant la vie des gens. Ces petits terminaux et terminaux très utiles besoin d'un substrat de communication globale pour fournir un service complet de l'utilisateur final global. En 2010, ITU -T a fourni les exigences pour supporter des applications et services USN dans le Next Generation Network (NGN) de l'environnement d'exploiter les avantages du réseau de base. L'un des principaux marchés prometteurs pour l'application et les services USN est la e- santé. Il fournit le suivi des patients en continu et permet une grande amélioration dans les services médicaux. D'autre part, des Véhicules Ad-hoc NETwork (VANET) est une technologie émergente qui permet une communication intelligente entre les véhicules mobiles. Intégrer VANET avec USN a un grand potentiel pour améliorer la sécurité routière et la fluidité du trafic. La plupart des applications VANET sont appliqués en temps réel et ils sont sensibles à retarder, en particulier ceux liés à la sécurité et à la santé. Dans ce travail, nous proposons d'utiliser l'IP Multimédia Subsystem (IMS) comme une sous- couche de contrôle de service dans l'environnement USN fournir un substrat mondiale pour un service complet de bout en bout. De plus, nous vous proposons d'intégrer VANETs avec USN pour des applications et des installations riches plus, ce qui facilitera la vie des humains. Nous avons commencé à étudier les défis sur la route pour atteindre cet objectif / Ubiquités Sensor Network (USN) is a conceptual network built over existing physical networks. It makes use of sensed data and provides knowledge services to anyone, anywhere and at anytime, and where the information is generated by using context awareness. Smart wearable devices and USNs are emerging rapidly providing many reliable services facilitating people life. Those very useful small end terminals and devices require a global communication substrate to provide a comprehensive global end user service. In 2010, the ITU-T provided the requirements to support USN applications and services in the Next Génération Network (NGN) environment to exploit the advantages of the core network. One of the main promising markets for the USN application and services is the e-Health. It provides continuous patients’ monitoring and enables a great improvement in medical services. On the other hand, Vehicular Ad-Hoc NETwork (VANET) is an emerging technology, which provides intelligent communication between mobile vehicles. Integrating VANET with USN has a great potential to improve road safety and traffic efficiency. Most VANET applications are applied in real time and they are sensitive to delay, especially those related to safety and health. In this work, we propose to use IP Multimedia Subsystem (IMS) as a service controller sub-layer in the USN environment providing a global substrate for a comprehensive end-to-end service. Moreover, we propose to integrate VANETs with USN for more rich applications and facilities, which will ease the life of humans. We started studying the challenges on the road to achieve this goal