End-to-end resource management for federated delivery of multimedia services

Recently, the Internet has become a popular platform for the delivery of multimedia content. Currently, multimedia services are either offered by Over-the-top (OTT) providers or by access ISPs over a managed IP network. As OTT providers offer their content across the best-effort Internet, they cannot offer any Quality of Service (QoS) guarantees to their users. On the other hand, users of managed multimedia services are limited to the relatively small selection of content offered by their own ISP. This article presents a framework that combines the advantages of both existing approaches, by dynamically setting up federations between the stakeholders involved in the content delivery process. Specifically, the framework provides an automated mechanism to set up end-to-end federations for QoS-aware delivery of multimedia content across the Internet. QoS contracts are automatically negotiated between the content provider, its customers, and the intermediary network domains. Additionally, a federated resource reservation algorithm is presented, which allows the framework to identify the optimal set of stakeholders and resources to include within a federation. Its goal is to minimize delivery costs for the content provider, while satisfying customer QoS requirements. Moreover, the presented framework allows intermediary storage sites to be included in these federations, supporting on-the-fly deployment of content caches along the delivery paths. The algorithm was thoroughly evaluated in order to validate our approach and assess the merits of including intermediary storage sites. The results clearly show the benefits of our method, with delivery cost reductions of up to 80 % in the evaluated scenario

Unified clustering and communication protocol for wireless sensor networks

In this paper we present an energy-efficient cross layer protocol for providing application specific reservations in wireless senor networks called the “Unified Clustering and Communication Protocol ” (UCCP). Our modular cross layered framework satisfies three wireless sensor network requirements, namely, the QoS requirement of heterogeneous applications, energy aware clustering and data forwarding by relay sensor nodes. Our unified design approach is motivated by providing an integrated and viable solution for self organization and end-to-end communication is wireless sensor networks. Dynamic QoS based reservation guarantees are provided using a reservation-based TDMA approach. Our novel energy-efficient clustering approach employs a multi-objective optimization technique based on OR (operations research) practices. We adopt a simple hierarchy in which relay nodes forward data messages from cluster head to the sink, thus eliminating the overheads needed to maintain a routing protocol. Simulation results demonstrate that UCCP provides an energy-efficient and scalable solution to meet the application specific QoS demands in resource constrained sensor nodes. Index Terms — wireless sensor networks, unified communication, optimization, clustering and quality of service

Qualité de service dans des environnements réseaux mobiles, contraints et hétérogènes

Les télécommunications sans fil ont connu ces dernières années un immense succès à tel point que le spectre des fréquences est désormais surchargé et nécessite la disponibilité de nouvelles ressources. Pour répondre à ce besoin, des techniques de réutilisation dynamique du spectre ont alors vu le jour sous la dénomination de radio cognitive. Elles consistent à partager de manière opportuniste et efficace certaines fréquences ayant été initialement allouées à d'autres systèmes. Cette thèse se place dans le contexte de réseaux sans fil tactiques hétérogènes comportant des segments de radios cognitives. La difficulté provient alors de la garantie de qualité de service de bout en bout : respect du débit négocié, du délai et de la gigue. Nous nous sommes tout d'abord intéressés au contrôle d'admission dans ce type de réseaux en proposant une méthode de calcul de bande passante résiduelle de bout en bout s'appuyant sur un algorithme de complexité polynomiale et pouvant être implanté de manière distribuée. Nous nous sommes ensuite concentrés sur le routage en proposant une nouvelle métrique tenant compte des particularités de ce type de réseaux. Enfin, nous nous focalisons sur la thématique du routage à contraintes multiples en étudiant et implantant en environnement réel des algorithmes d'approximation proposés dans la littérature. ABSTRACT : The unprecedented success of wireless telecommunication systems has resulted in the wireless spectrum becoming a scarce resource. Cognitive Radio systems have been proposed as the enabling technology allowing unlicensed equipments to opportunistically access the licensed spectrum when not in use by the licensed users. The focus of this thesis is on heterogeneous tactical networks deploying cognitive radios in parts or in their entirety. Such networks can be organized in multiple sub-networks, each characterized by a specific topology, medium access scheme and spectrum access policy. As a result, providing end-to-end Quality of Service guarantees in terms of bandwidth, delay and jitter, emerges as a key challenge. We first address the admission control in multi-hop cognitive radio networks and propose a polynomial time algorithm that can be implemented in a distributed fashion for estimating the end-to-end bandwidth. Then, we focus on routing and propose a new metric that takes into account the specifics of such networks. Finally, as quality of service requirements can be expressed using multiple metrics, we turn our attention to multi-constrained routing and implement on a real testbed low complexity approximation algorithms

Path Computation for Resilient Networking

Τα τρέχοντα συστήματα τηλεπικοινωνιών απαιτούνε αρχιτεκτονική υψηλής ποιότητας υπηρεσιών (QoS – Quality of Service) και υψηλή ανοχή σε τυχόν προβλήματα και καταστροφές στο δίκτυο. Αυτό συμβαίνει καθώς η πολιτεία, οι κυβερνητικοί και στρατιωτικοί οργανισμοί, οι εταιρείες και ολόκληρη η κοινωνία στηρίζεται όλο και περισσότερο στα δίκτυα και τις τηλεπικοινωνίες για τις καθημερινές δραστηριότητες τους. Επομένως, η διαθεσιμότητα τους είναι εξαιρετικά σημαντική και οποιαδήποτε βλάβη σε αυτά μπορεί να δημιουργήσει τεράστια προβλήματα. Για αυτό το λόγο, η δημιουργία εύρωστων και στιβαρών δικτύων χρήζει τεράστιας σημασίας και μια καλή προσέγγιση για την πραγματοποίηση τους είναι η προστασία των μονοπατιών και η γρήγορη αποκατάσταση του δικτύου. Οι κυβερνητικοί και στρατιωτικοί οργανισμοί, σκοπεύοντας να αυξήσουν την διαθεσιμότητα και την ελαστικότητα των πληροφοριακών συστημάτων τους, στηρίζονται σε διαφορετικά δίκτυα για την διασύνδεση των σταθμότοπων τους, όπως για παράδειγμα σε υποδομές ιδιωτικών δικτύων, δημόσιους παρόχους Ιnternet, δορυφορικά δίκτυα και τακτικές ζεύξεις δεδομένων. Αυτή η προσέγγιση ονομάζεται πολυεστίαση (multihoming) και χρησιμοποιείται για να προστατέψει τις αναπτυσσόμενες υπηρεσίες από πιθανή κακή λειτουργία που προκαλείται από βλάβες του δικτύου. Πράγματι, όταν μια βλάβη πραγματοποιηθεί σε ένα από τα δίκτυα, η δρομολόγηση κίνησης γίνεται μέσω άλλου δικτύου αυτόματα λειτουργώντας σαν εφεδρική λύση. Παρόλα αυτά, αν και ο συγκεκριμένος τρόπος προστασίας των διαδρομών φαίνεται να είναι μια καλή λύση για την αύξηση της ελαστικότητας των δικτύων, η αποτελεσματικότητα και η απόδοση του εξαρτάται από την εγκαθίδρυση μια πλήρους διαπλεγμένης διασυνδεσιμότητας (full mesh interconnectivity) μεταξύ όλων των σταθμότοπων. Αυτή η προσέγγιση έχει τεράστιο κόστος και δεν είναι πάντα χρήσιμη εφόσον όλες οι υπηρεσίες δεν έχουν το ίδιο επίπεδο κρισιμότητας. Η παρούσα εργασία παρουσιάζει ένα σύνολο αλγορίθμων υπολογισμού μονοπατιών (path computation algorithms) που μελετήθηκαν και επεκτάθηκαν έτσι ώστε να λαμβάνουν υπόψη τις απαιτήσεις των τελικών χρηστών (κρισιμότητα, ασφάλεια, προστασία) στην εύρεση πρωτεύοντος αλλά και δευτερεύοντος μονοπατιού. Η ευρωστία σε βλάβες και το κόστος της τεχνικής αποκατάστασης του δικτύου αξιολογούνται σε ένα στρατιωτικό σενάριο, όπου οι σταθμότοποι είναι διασυνδεδεμένοι διαμέσου τριών δικτύων πρόσβασης.Current information systems require a very good quality of service (QoS) architecture and high tolerance to failures and disasters. Indeed, states, governmental and military organisations, companies and also the whole society rely more and more on the network for their daily activities. Therefore, the availability of those networks is crucial and any impairment can be dramatic. Building robust and resilient networks is mandatory and path protection and fast restoration appear to be a very good approach. In order to increase the availability and resilience of their information systems, governmental and military organizations may rely on different networks to interconnect their sites such as private infrastructure networks, public ISP networks, SATCOM, tactical data links. This approach, called multi-homing is used to protect deployed services from impairments caused by potential network failures. Indeed, when a failure occurs on one of the networks, the traffic is automatically redirected on the other networks that serve as backup. However, although this protection scheme appears to be a good solution to increase the resilience of networks, its effectiveness and performance depends on the setup of full mesh interconnectivity between all the sites on each transit network. This approach is extremely costly and not always useful since all the services do not have the same operational criticality. The existing work presents a set of path computation algorithms that were studied and extended to include the end user requirements (criticality, security, protection) in the establishment of both primary and backup paths. The robustness to faults and the cost by the setup of the protection scheme are evaluated in a military scenario where the sites are interconnected through three access networks

Fast Converging Evolutionary Strategy for Multi-Constraint QoS Routing in Computer Networks Using New Decoding Mechanism

In recent years, real-time multimedia applications' demands such as Voice-on-IP (VoIP) and video conference are extremely increased which require QoS routing. This type of routing has been considered as an NP-Complete problem since it requires satisfying multiple constraints. Many solutions have been proposed to solve it, but most of them are complex and time consuming. In this paper, a novel multi-constraints QoS routing algorithm is proposed based on Evolutionary Strategies (ES). The algorithm preserves simplicity and offers a feasible solution in a few numbers of generations. This is due to a novel gene decoding mechanism that is used in the algorithm; and consequently more simple evolutionary operators can be applied. The simulation results show that our method outperforms previous algorithms in terms of speed and performance, so that it is 2.6 and 11.3 times faster, and its success ratio is also better

Service-Driven Networking

This thesis presents our research on service-driven networking, which is a general design framework for service quality assurance and integrated network and service management in large scale multi-domain networks. The philosophy is to facilitate bi-party open participation among the users and the providers of network services in order to bring about better service customization and quality assurance, without sacrificing the autonomy and objectives of the individual entities. Three primary research topics are documented: service composition and adaptation, self-stabilization in uncoordinated environment, and service quality modeling. The work involves theoretical analysis, algorithm design, and simulations as evaluation methodology

An improved particle swarm algorithm for multi-objectives based optimization in MPLS/GMPLS networks

Particle swarm optimization (PSO) is a swarm-based optimization technique capable of solving different categories of optimization problems. Nevertheless, PSO has a serious exploration issue that makes it a difficult choice for multi-objectives constrained optimization problems (MCOP). At the same time, Multi-Protocol Label Switched (MPLS) and its extended version Generalized MPLS, has become an emerging network technology for modern and diverse applications. Therefore, as per MPLS and Generalized MPLS MCOP needs, it is important to find the Pareto based optimal solutions that guarantee the optimal resource utilization without compromising the quality of services (QoS) within the networks. The paper proposes a novel version of PSO, which includes a modified version of the Elitist Learning Strategy (ELS) in PSO that not only solves the existing exploration problem in PSO, but also produces optimal solutions with efficient convergence rates for different MPLS/ GMPLS network scales. The proposed approach has also been applied with two objective functions; the resource provisioning and the traffic load balancing costs. Our simulations and comparative study showed improved results of the proposed algorithm over the well-known optimization algorithms such as the “standard” PSO, Adaptive PSO, BAT, and Dolphin algorithm