Algorithme de maintien de cohérence dans les bases de données réparties sur grappes d'ordinateurs

Modèles et algorithmes de maintien de cohérence -- Nouvel algorithme de gestion des accès -- Critères de sélection d'un algorithme de gestion des transactions -- Description d'une grappe d'ordinateurs : exemple de TelORB -- Description de quelques algorithmes sélectionnés -- Analyse de performance -- Implémentation et mise en oeuvre -- Modélisation de la BDR -- Les classes d'objets utilisés dans le programme -- Les classes modélisant les composantes du SGBDR -- L'outil de simulation CSIM18 -- Programme de simulation -- Mise en oeuvre du programme de simulation -- Analyse des résultats -- Plan d'expériences -- Comportement d'un SGBDR en mémoire vive -- Comportement d'un SGBDR sur disque -- Comportement d'un SGBDR avec réplication de données -- Comportement d'un SGBDR de temps réel -- Synthèse des résultats de simulation -- Résultats expérimentaux sur DBN -- Améliorations proposées pour DBN

NFV Orchestrator Placement for Geo-Distributed Systems

The European Telecommunications Standards Institute (ETSI) developed Network Functions Virtualization (NFV) Management and Orchestration (MANO) framework. Within that framework, NFV orchestrator (NFVO) and Virtualized Network Function (VNF) Manager (VNFM) functional blocks are responsible for managing the lifecycle of network services and their associated VNFs. However, they face significant scalability and performance challenges in large-scale and geo-distributed NFV systems. Their number and location have major implications for the number of VNFs that can be accommodated and also for the overall system performance. NFVO and VNFM placement is therefore a key challenge due to its potential impact on the system scalability and performance. In this paper, we address the placement of NFVO and VNFM in large-scale and geo-distributed NFV infrastructure. We provide an integer linear programming formulation of the problem and propose a two-step placement algorithm to solve it. We also conduct a set of experiments to evaluate the proposed algorithm.Comment: This paper has been accepted for presentation in 16th IEEE International Symposium on Network Computing and Applications (IEEE NCA 2017

A Virtual Network PaaS for 3GPP 4G and Beyond Core Network Services

Cloud computing and Network Function Virtualization (NFV) are emerging as key technologies to overcome the challenges facing 4G and beyond mobile systems. Over the last few years, Platform-as-a-Service (PaaS) has gained momentum and has become more widely adopted throughout IT enterprises. It simplifies the applications provisioning and accelerates time-to-market while lowering costs. Telco can leverage the same model to provision the 4G and beyond core network services using NFV technology. However, many challenges have to be addressed, mainly due to the specificities of network services. This paper proposes an architecture for a Virtual Network Platform-as-a-Service (VNPaaS) to provision 3GPP 4G and beyond core network services in a distributed environment. As an illustrative use case, the proposed architecture is employed to provision the 3GPP Home Subscriber Server (HSS) as-a-Service (HSSaaS). The HSSaaS is built from Virtualized Network Functions (VNFs) resulting from a novel decomposition of HSS. A prototype is implemented and early measurements are made.Comment: 7 pages, 6 figures, 2 tables, 5th IEEE International Conference on Cloud Networking (IEEE CloudNet 2016