Cloudifying the 3GPP IP Multimedia Subsystem: Why and How?

The 3GPP IP Multimedia Subsystem (IMS) has been specified as the service delivery platform of 3G networks. It subsequently became the de facto service delivery platform of 4G networks. Cloud computing is an emerging paradigm with inherent benefits such as scalability, elasticity and easy deployment of new applications and services. Scalability and elasticity are currently among the major roadblocks to the wide scale deployment of IMS. Cloudifying IMS can help in removing these roadblocks. It will also certainly bring many other advantages. However, this cloudification is no easy task and is still in its infancy. This paper motivates the cloudification of IMS, critically review the architectures proposed so far, sketch a vision and discusses the related research challenges

Network convergence and QoS for future multimedia services in the VISION project

The emerging use of real-time 3D-based multimedia applications imposes strict quality of service (QoS) requirements on both access and core networks. These requirements and their impact to provide end-to-end 3D videoconferencing services have been studied within the Spanish-funded VISION project, where different scenarios were implemented showing an agile stereoscopic video call that might be offered to the general public in the near future. In view of the requirements, we designed an integrated access and core converged network architecture which provides the requested QoS to end-to-end IP sessions. Novel functional blocks are proposed to control core optical networks, the functionality of the standard ones is redefined, and the signaling improved to better meet the requirements of future multimedia services. An experimental test-bed to assess the feasibility of the solution was also deployed. In such test-bed, set-up and release of end-to-end sessions meeting specific QoS requirements are shown and the impact of QoS degradation in terms of the user perceived quality degradation is quantified. In addition, scalability results show that the proposed signaling architecture is able to cope with large number of requests introducing almost negligible delay

Ensuring interoperability between network elements in next generation networks

Next Generation Networks (NGNs), based on the Internet Protocol (IP), implement several services such as IP-based telephony and are beginning to replace the classic telephony systems. Due to the development and implementation of new powerful services these systems are becoming increasingly complex. Implementing these new services (typically software-based network elements) is often accompanied by unexpected and erratic behaviours which can manifest as interoperability problems. The reason for this caused by insufficient testing at the developing companies. The testing of such products is by nature a costly and time-consuming exercise and therefore cut down to what is considered the maximum acceptable level. Ensuring the interoperability between network elements is a known challenge. However, there exists no concept of which testing methods should be utilised to achieve an acceptable level of quality. The objective of this thesis was to improve the interoperability between network elements in NGNs by creating a testing scheme comprising of three diverse testing methods: conformance testing, interoperability testing and posthoc analysis. In the first project a novel conformance testing methodology for developing sets of conformance test cases for service specifications in NGNs was proposed. This methodology significantly improves the chance of interoperability and provides a considerable enhancement to the currently used interoperability tests. It was evaluated by successfully applying it to the Presence Service. The second report proposed a post-hoc methodology which enables the identification of the ultimate causes for interoperability problems in a NGN in daily operation. The new methods were implemented in the tool IMPACT (IP-Based Multi Protocol Posthoc Analyzer and Conformance Tester), which stores all exchanged messages between network elements in a database. Using SQL queries, the causes for errors can be found efficiently. Overall the presented testing scheme improves significantly the chance that network elements interoperate successfully by providing new methods. Beyond that, the quality of the software product is raised by mapping these methods to phases in a process model and providing well defined steps on which test method is the best suited at a certain stage

Optimum hybrid error correction scheme under strict delay constraints

In packet-based wireless networks, media-based services often require a multicast-enabled transport that guarantees quasi error free transmission under strict delay constraints. Furthermore, both multicast and delay constraints deeply influence the architecture of erasure error recovery (EER). Therefore, we propose a general architecture of EER and study its optimization in this thesis. The architecture integrates overall existing important EER techniques: Automatic Repeat Request, Forward Error Correction and Hybrid ARQ techniques. Each of these EER techniques can be viewed as a special case of Hybrid Error Correction (HEC) schemes. Since the Gilbert-Elliott (GE) erasure error model has been proven to be valid for a wide range of packet based wireless networks, in this thesis, we present the general architecture and its optimization based on the GE channel model. The optimization target is to satisfy a certain target packet loss level under strict delay constraints efficiently. Through the optimization for a given real-time multicast scenario, the total needed redundancy information can be minimized by choosing the best HEC scheme automatically among the entire schemes included in the architecture. As a result, the performance of the optimum HEC scheme can approach the Shannon limit as closely as possible dynamically according to current channel state information.In Paket-basierten drahtlosen Netzwerken benötigen Medien-basierte Dienste oft Multicast-fähigen Transport, der quasi-fehlerfreie Übertragung unter strikten Zeitgrenzen garantiert. Außerdem beeinflussen sowohl Multicast als auch Zeitbegrenzungen stark die Architektur von Auslöschungs-Fehlerschutz (Erasure Error Recovery, EER). Daher stellen wir eine allgemeine Architektur der EER vor und untersuchen ihre Optimierung in dieser Arbeit. Die Architektur integriert alle wichtigen EER-Techniken: Automatic Repeat Request, Forward Error Correction und Hybrid ARQ. Jede dieser EER-Techniken kann als Spezialfall der Hybrid Error Correction (HEC) angesehen werden. Da das Gilbert-Elliot (GE) Auslöschungs-Fehler-Modell für einen weiten Bereich von Paket-basierten drahtlosen Netzwerken als gültig erwiesen wurde, präsentieren wir in dieser Arbeit die allgemeine Architektur und deren Optimierung basierend auf dem GE Kanalmodell. Zweck der Optimierung ist es, eine gewisse Ziel-Paketfehlerrate unter strikten Zeitgrenzen effizient zu erreichen. Durch die Optimierung für ein gegebenes Echtzeit-Mutlicast-Szenario kann die insgesamt benötigte Redundanz-Information minimiert werden. Dies erfolgt durch automatische Auswahl des optimalen HEC Schemas unter all den Schemata, die in die Architektur integriert sind. Das optimale HEC-Schema kann die Shannon Grenze so nahe wie möglich, dynamisch, entsprechend dem derzeitigen Kanalzustand, erreichen

Les opérateurs sauront-ils survivre dans un monde en constante évolution? Considérations techniques conduisant à des scénarios de rupture

Le secteur des télécommunications passe par une phase délicate en raison de profondes mutations technologiques, principalement motivées par le développement de l'Internet. Elles ont un impact majeur sur l'industrie des télécommunications dans son ensemble et, par conséquent, sur les futurs déploiements des nouveaux réseaux, plateformes et services. L'évolution de l'Internet a un impact particulièrement fort sur les opérateurs des télécommunications (Telcos). En fait, l'industrie des télécommunications est à la veille de changements majeurs en raison de nombreux facteurs, comme par exemple la banalisation progressive de la connectivité, la domination dans le domaine des services de sociétés du web (Webcos), l'importance croissante de solutions à base de logiciels et la flexibilité qu'elles introduisent (par rapport au système statique des opérateurs télécoms). Cette thèse élabore, propose et compare les scénarios possibles basés sur des solutions et des approches qui sont technologiquement viables. Les scénarios identifiés couvrent un large éventail de possibilités: 1) Telco traditionnel; 2) Telco transporteur de Bits; 3) Telco facilitateur de Plateforme; 4) Telco fournisseur de services; 5) Disparition des Telco. Pour chaque scénario, une plateforme viable (selon le point de vue des opérateurs télécoms) est décrite avec ses avantages potentiels et le portefeuille de services qui pourraient être fournisThe telecommunications industry is going through a difficult phase because of profound technological changes, mainly originated by the development of the Internet. They have a major impact on the telecommunications industry as a whole and, consequently, the future deployment of new networks, platforms and services. The evolution of the Internet has a particularly strong impact on telecommunications operators (Telcos). In fact, the telecommunications industry is on the verge of major changes due to many factors, such as the gradual commoditization of connectivity, the dominance of web services companies (Webcos), the growing importance of software based solutions that introduce flexibility (compared to static system of telecom operators). This thesis develops, proposes and compares plausible future scenarios based on future solutions and approaches that will be technologically feasible and viable. Identified scenarios cover a wide range of possibilities: 1) Traditional Telco; 2) Telco as Bit Carrier; 3) Telco as Platform Provider; 4) Telco as Service Provider; 5) Telco Disappearance. For each scenario, a viable platform (from the point of view of telecom operators) is described highlighting the enabled service portfolio and its potential benefitsEVRY-INT (912282302) / SudocSudocFranceF