This thesis proposes a new algorithm for multi-constrained Quality of Service Optimal Path Routing in the context of military applications. The objective of our routing algorithm is to manage network traffic according to quality of service requirements of connection requests using military metrics. The algorithm is mainly based on communication priority. The QoS metrics such as bandwidth, delay and packet loss ratio are considered as basic metrics on path finding. If there is no suitable path for the request, some existing connections with lower priorities may be broken to make space for a higher priority level connection request. In this case, priority and bandwidth are used as decisive metrics in cost computation

Orientador: Edmundo Roberto Mauro Madeira / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Computação / Made available in DSpace on 2018-08-11T08:18:18Z (GMT). No. of bitstreams: 1 Paschoalino_RacheldeCarvalho_M.pdf: 2064052 bytes, checksum: e9b127c3cba93b04b66044600728e3a9 (MD5) Previous issue date: 2008 / Resumo: Devido à facilidade de implantação e gerência, as redes mesh sem fio constituem uma escolha natural para atender a crescente demanda por acesso sem fio com cobertura em larga escala. Formadas por roteadores mesh interligados através de enlaces sem fio, as WMNs (Wireless Mesh Networks) fornecem um backbone flexível para diversas aplicações e serviços. Entretanto, os protocolos de roteamento existentes aplicados às WMNs não provêem escalabilidade, reduzindo a vazão conforme o tamanho da rede aumenta. Esta dissertação apresenta um protocolo de roteamento escalável com QoS para WMNs multirádio. Incorporamos uma métrica local de qualidade do enlace e suporte a múltiplos rádios ao protocolo OLSR (Optimized Link State Routing). A métrica de qualidade é usada na seleção de nós especiais de relay, que irão compor as rotas. Variações na métrica de qualidade são tratadas na vizinhança de 1 salto, preservando estabilidade no roteamento. Por sua vez, o uso de múltiplos rádios por nó provê um melhor aproveitamento do espectro sem fio, minimizando a contenção. Essa abordagem simples e escalável permite distribuir o tráfego na rede por caminhos com enlaces de melhor qualidade. Através das simulações realizadas, demonstramos que o protocolo proposto, chamado LQ-OLSR (Link Quality OLSR), traz melhorias expressivas na vazão, atraso e perda de pacotes em relação ao OLSR original, com um aumento mínimo do overhead / Abstract: Due to their deployment and management simplicity, Wireless Mesh Networks (WMNs) have become a natural way to fulfill the increasing demand for large area wireless coverage. Formed by mesh routers connected by wireless links, WMNs provide a flexible backbone for various applications and services. Nevertheless, the available routing protocols applied to WMNs suffer from scalability, where throughput decreases as the number of nodes grows. In this thesis, a scalable QoS routing protocol for multi-radio WMNs is proposed. We incorporate a locallink quality metric and multi-radio support in the OLSR (Optimized Link State Routing) protocol. The quality metric is used in the selection of relay nodes which will form the routes. Significant changes to link quality metric are treated in l-hop neighborhood, preserving route stability. Using multiple radios in each node allows a better utilization of the wireless spectrum, minimizing contention. This simple and scalable approach permits traffic distribution among better quality links. Simulations were conducted and the results showed expressive performance improvements .concerning throughput, delay and packet loss of the proposed protocol LQ-OLSR (Link Quality OLSR) over the original OLSR, with a minimum overhead increase / Mestrado / Redes de Computadores / Mestre em Ciência da Computação

Quality of Service (QoS) routing considered as one of the major components of the QoS framework in communication networks. The concept of QoS routing has emerged from the fact that routers direct traffic from source to destination, depending on data types, network constraints and requirements to achieve network performance efficiency. It has been introduced to administer, monitor and improve the performance of computer networks. Many QoS routing algorithms are used to maximize network performance by balancing traffic distributed over multiple paths. Its major components include bandwidth, delay, jitter, cost, and loss probability in order to measure the end users¿ requirements, optimize network resource usage and balance traffic load. The majority of existing QoS algorithms require the maintenance of the global network state information and use it to make routing decisions. The global QoS network state needs to be exchanged periodically among routers since the efficiency of a routing algorithm depends on the accuracy of link-state information. However, most of QoS routing algorithms suffer from scalability problems, because of the high communication overhead and the high computation effort associated with marinating and distributing the global state information to each node in the network.The goal of this thesis is to contribute to enhancing the scalability of QoS routing algorithms. Motivated by this, the thesis is focused on localized QoS routing that is proposed to achieve QoS guarantees and overcome the problems of using global network state information such as high communication overhead caused by frequent state information updates, inaccuracy of link-state information for large QoS state update intervals and the route oscillating due to the view of state information. Using such an approach, the source node makes its own routing decisions based on the information that is local to each node in the path. Localized QoS routing does not need the global network state to be exchanged among network nodes because it infers the network state and avoids all the problems associated with it, like high communication and processing overheads and oscillating behaviour. In localized QoS routing each source node is required to first determine a set of candidate paths to each possible destination. In this thesis we have developed localized QoS routing algorithms that select a path based on its quality to satisfy the connection requirements. In the first part of the thesis a localized routing algorithm has been developed that relies on the average residual bandwidth that each path can support to make routing decisions. In the second part of the thesis, we have developed a localized delay-based QoS routing (DBR) algorithm which relies on a delay constraint that each path satisfies to make routing decisions. We also modify credit-based routing (CBR) so that this uses delay instead of bandwidth. Finally, we have developed a localized QoS routing algorithm for routing in two levels of a hierarchal network and this relies on residual bandwidth to make routing decisions in a hierarchical network like the internet. We have compared the performance of the proposed localized routing algorithms with other localized and global QoS routing algorithms under different ranges of workloads, system parameters and network topologies. Simulation results have indicated that the proposed algorithms indeed outperform algorithms that use the basics of schemes that currently operate on the internet, even for a small update interval of link state. The proposed algorithms have also reduced the routing overhead significantly and utilize network resources efficiently.

School of Computing, Informatics and Media / Localised QoS routing is a relatively new, alternative and viable approach to solve the problems of traditional QoS routing algorithms which use global state information resulting in the imposition of a large communication overhead and route flapping. They make use of a localised view of the network QoS state in source nodes to select paths and route flows to destination nodes. Proportional Sticky Routing (PSR) and Credit Based Routing (CBR) have been proposed as localised QoS routing schemes and these can offer comparable performances. However, since network state information for a specific path is only updated when the path is used, PSR and CBR operate with decision criteria that are often stale for paths that are used infrequently. The aim of this thesis is to focus on localised QoS routing and contribute to enhancing the scalability of QoS routing algorithms. In this thesis we have developed three new localised QoS routing schemes which are called Score Based QoS Routing (SBR), Bandwidth Based QoS Routing (BBR) and Delay Based Routing (DBR). In some of these schemes, the path setup procedure is distributed and uses the current network state to make decisions thus avoiding problems of staleness. The methods also avoid any complicated calculations. Both SBR and BBR use bandwidth as the QoS metric and mean delay is used as the QoS metric in DBR. Extensive simulations are applied to compare the performance of our proposed algorithms with CBR and the global Dijkstra¿s algorithm for different update intervals of link state, different network topologies and using different flow arrival distributions under a wide range of traffic loads. It is demonstrated by simulation that the three proposed algorithms offer a superior performance under comparable conditions to the other localised and global algorithms.

No / Localized Quality of Service (QoS) routing has recently been proposed as a viable alternative approach to traditional QoS routing algorithms that use global state information. In this approach, problems associated with maintaining global state information and the staleness of such information are avoided by having the source nodes to infer the network QoS state based on flow blocking statistics collected locally, and perform flow routing using this localized view of the network QoS state . In this paper we introduce a credit based routing algorithm (cbr) which is a simple yet effective localized QoS routing algorithm. We compare its performance against the localized proportional sticky routing (psr) algorithm same time complexity. using different types of network topologies, QoS requirements and traffic patterns and under a wide range of traffic loads. Extensive simulations show that our algorithm outperforms the psr algorithm with the same time complexity.

The growing demand on the variety of internet applications requires management of large scale networks by efficient Quality of Service (QoS) routing, which considerably contributes to the QoS architecture. The biggest contemporary drawback in the maintenance and distribution of the global state is the increase in communication overheads. Unbalancing in the network, due to the frequent use of the links assigned to the shortest path retaining most of the network loads is regarded as a major problem for best effort service. Localised QoS routing, where the source nodes use statistics collected locally, is already described in contemporary sources as more advantageous. Scalability, however, is still one of the main concerns of existing localised QoS routing algorithms. The main aim of this thesis is to present and validate new localised algorithms in order to develop the scalability of QoS routing. Existing localised routing, Credit Based Routing (CBR) and Proportional Sticky Routing (PSR), use the blocking probability as a factor in selecting the routing paths and work with either credit or flow proportion respectively, which makes impossible having up-to-date information. Therefore our proposed Highest Minimum Bandwidth (HMB) and Highest Average Bottleneck Bandwidth History (HABBH) algorithms utilise bandwidth as the direct QoS criterion to select routing paths. We introduce an Integrated Delay Based Routing and Admission Control mechanism. Using this technique Minimum Total Delay (MTD), Low Fraction Failure (LFF) and Low Path Failure (LPF) were compared against the global QoS routing scheme, Dijkstra, and localised High Path Credit (HPC) scheme and showed superior performance. The simulation with the non-uniformly distributed traffic reduced blocking probability of the proposed algorithms. Therefore, we advocate the algorithms presented in the thesis, as a scalable approach to control large networks. We strongly suggest that bandwidth and mean delay are feasible QoS constraints to select optimal paths by locally collected information. We have demonstrated that a few good candidate paths can be selected to balance the load in the network and minimise communication overhead by applying the disjoint paths method, recalculation of candidate paths set and dynamic paths selection method. Thus, localised QoS routing can be used as a load balancing tool in order to improve the network resource utilization. A delay and bandwidth combination is one of the future prospects of our work, and the positive results presented in the thesis suggest that further development of a distributed approach in candidate paths selection may enhance the proposed localised algorithms.

The exponential growth of Internet applications has created new challenges for the control and administration of large-scale networks, which consist of heterogeneous elements under dynamically changing traffic conditions. These emerging applications need guaranteed service levels, beyond those supported by best-effort networks, to deliver the intended services to the end user. Several models have been proposed for a Quality of Service (QoS) framework that can provide the means to transport these services. It is desirable to find efficient routing strategies that can meet the strict routing requirements of these applications. QoS routing is considered as one of the major components of the QoS framework in communication networks. In QoS routing, paths are selected based upon the knowledge of resource availability at network nodes and the QoS requirements of traffic. Several QoS routing schemes have been proposed that differ in the way they gather information about the network state and the way they select paths based on this information. The biggest downside of current QoS routing schemes is the frequent maintenance and distribution of global state information across the network, which imposes huge communication and processing overheads. Consequently, scalability is a major issue in designing efficient QoS routing algorithms, due to the high costs of the associated overheads. Moreover, inaccuracy and staleness of global state information is another problem that is caused by relatively long update intervals, which can significantly deteriorate routing performance. Localized QoS routing, where source nodes take routing decisions based solely on statistics collected locally, was proposed relatively recently as a viable alternative to global QoS routing. It has shown promising results in achieving good routing performance, while at the same time eliminating many scalability related problems. In localized QoS routing each source-destination pair needs to determine a set of candidate paths from which a path will be selected to route incoming flows. The goal of this thesis is to enhance the scalability of QoS routing by investigating and developing new models and algorithms based on the localized QoS routing approach. For this thesis, we have extensively studied the localized QoS routing approach and demonstrated that it can achieve a higher routing performance with lower overheads than global QoS routing schemes. Existing localized routing algorithms, Proportional Sticky Routing (PSR) and Credit-Based Routing (CBR), use the blocking probability of candidate paths as the criterion for selecting routing paths based on either flow proportions or a crediting mechanism, respectively. Routing based on the blocking probability of candidate paths may not always reflect the most accurate state of the network. This has motivated the search for alternative localized routing algorithms and to this end we have made the following contributions. First, three localized bandwidth-constrained QoS routing algorithms have been proposed, two are based on a source routing strategy and the third is based on a distributed routing strategy. All algorithms utilize the quality of links rather than the quality of paths in order to make routing decisions. Second, a dynamic precautionary mechanism was used with the proposed algorithms to prevent candidate paths from reaching critical quality levels. Third, a localized delay-constrained QoS routing algorithm was proposed to provide routing with an end-to-end delay guarantee. We compared the performance of the proposed localized QoS routing algorithms with other localized and global QoS routing algorithms under different network topologies and different traffic conditions. Simulation results show that the proposed algorithms outperform the other algorithms in terms of routing performance, resource balancing and have superior computational complexity and scalability features.

The exponential growth of Internet applications has created new challenges for the control and administration of large-scale networks, which consist of heterogeneous elements under dynamically changing traffic conditions. These emerging applications need guaranteed service levels, beyond those supported by best-effort networks, to deliver the intended services to the end user. Several models have been proposed for a Quality of Service (QoS) framework that can provide the means to transport these services. It is desirable to find efficient routing strategies that can meet the strict routing requirements of these applications. QoS routing is considered as one of the major components of the QoS framework in communication networks. In QoS routing, paths are selected based upon the knowledge of resource availability at network nodes and the QoS requirements of traffic. Several QoS routing schemes have been proposed that differ in the way they gather information about the network state and the way they select paths based on this information. The biggest downside of current QoS routing schemes is the frequent maintenance and distribution of global state information across the network, which imposes huge communication and processing overheads. Consequently, scalability is a major issue in designing efficient QoS routing algorithms, due to the high costs of the associated overheads. Moreover, inaccuracy and staleness of global state information is another problem that is caused by relatively long update intervals, which can significantly deteriorate routing performance. Localized QoS routing, where source nodes take routing decisions based solely on statistics collected locally, was proposed relatively recently as a viable alternative to global QoS routing. It has shown promising results in achieving good routing performance, while at the same time eliminating many scalability related problems. In localized QoS routing each source¿destination pair needs to determine a set of candidate paths from which a path will be selected to route incoming flows. The goal of this thesis is to enhance the scalability of QoS routing by investigating and developing new models and algorithms based on the localized QoS routing approach. For this thesis, we have extensively studied the localized QoS routing approach and demonstrated that it can achieve a higher routing performance with lower overheads than global QoS routing schemes. Existing localized routing algorithms, Proportional Sticky Routing (PSR) and Credit-Based Routing (CBR), use the blocking probability of candidate paths as the criterion for selecting routing paths based on either flow proportions or a crediting mechanism, respectively. Routing based on the blocking probability of candidate paths may not always reflect the most accurate state of the network. This has motivated the search for alternative localized routing algorithms and to this end we have made the following contributions. First, three localized bandwidth-constrained QoS routing algorithms have been proposed, two are based on a source routing strategy and the third is based on a distributed routing strategy. All algorithms utilize the quality of links rather than the quality of paths in order to make routing decisions. Second, a dynamic precautionary mechanism was used with the proposed algorithms to prevent candidate paths from reaching critical quality levels. Third, a localized delay-constrained QoS routing algorithm was proposed to provide routing with an end-to-end delay guarantee. We compared the performance of the proposed localized QoS routing algorithms with other localized and global QoS routing algorithms under different network topologies and different traffic conditions. Simulation results show that the proposed algorithms outperform the other algorithms in terms of routing performance, resource balancing and have superior computational complexity and scalability features. / Umm AlQura University, Saudi Arabia

The growing demand on the variety of internet applications requires management of large scale networks by efficient Quality of Service (QoS) routing, which considerably contributes to the QoS architecture. The biggest contemporary drawback in the maintenance and distribution of the global state is the increase in communication overheads. Unbalancing in the network, due to the frequent use of the links assigned to the shortest path retaining most of the network loads is regarded as a major problem for best effort service. Localised QoS routing, where the source nodes use statistics collected locally, is already described in contemporary sources as more advantageous. Scalability, however, is still one of the main concerns of existing localised QoS routing algorithms. The main aim of this thesis is to present and validate new localised algorithms in order to develop the scalability of QoS routing. Existing localised routing, Credit Based Routing (CBR) and Proportional Sticky Routing (PSR), use the blocking probability as a factor in selecting the routing paths and work with either credit or flow proportion respectively, which makes impossible having up-to-date information. Therefore our proposed Highest Minimum Bandwidth (HMB) and Highest Average Bottleneck Bandwidth History (HABBH) algorithms utilise bandwidth as the direct QoS criterion to select routing paths. We introduce an Integrated Delay Based Routing and Admission Control mechanism. Using this technique Minimum Total Delay (MTD), Low Fraction Failure (LFF) and Low Path Failure (LPF) were compared against the global QoS routing scheme, Dijkstra, and localised High Path Credit (HPC) scheme and showed superior performance. The simulation with the non-uniformly distributed traffic reduced blocking probability of the proposed algorithms. Therefore, we advocate the algorithms presented in the thesis, as a scalable approach to control large networks. We strongly suggest that bandwidth and mean delay are feasible QoS constraints to select optimal paths by locally collected information. We have demonstrated that a few good candidate paths can be selected to balance the load in the network and minimise communication overhead by applying the disjoint paths method, recalculation of candidate paths set and dynamic paths selection method. Thus, localised QoS routing can be used as a load balancing tool in order to improve the network resource utilization. A delay and bandwidth combination is one of the future prospects of our work, and the positive results presented in the thesis suggest that further development of a distributed approach in candidate paths selection may enhance the proposed localised algorithms. / Umm AlQura University in Mecca

La thèse porte sur la conception de protocoles de routage pour les réseaux de capteurs. Les problèmes de recherche du routage de données dans un réseau multi-sauts sont d’une part l’optimisation de l’énergie et d’autre part le routage sous contraintes de la qualité de service (QoS) multicritères (e.g., énergie, fiabilité, délai, …). Cette thèse apporte deux contributions par rapport à l’état de l’art : une optimisation d'un protocole de routage probabiliste pour l'équilibre de l'usage d'énergie et un protocole de routage capable de prendre en compte simultanément des métriques de QoS multiples. En effet, pour équilibrer la consommation de l’énergie du routage lorsque des chemins multiples existent, les protocoles de routage probabiliste existants affectent une probabilité de choix à chaque chemin, soit de façon empirique, soit proportionnelle au niveau de l’énergie disponible du chemin. Nous ne savions pas quelles sont les probabilités optimales qui permettent d’avoir la durée de vie maximale du réseau. Cette thèse a permis d’établir ces probabilités optimales à l’aide de la modélisation sous forme d’un problème d’optimisation linéaire. Quant au problème du routage multicritères, bien que des métriques multiples soient définies par RPL (un standard d’IETF), les protocoles existants choisissent la route soit sur une métrique, soit sur une fonction de coût combinant plusieurs (qui introduit par conséquent un biais de pondération), mais jamais plusieurs simultanément. Dans cette thèse, nous avons d’abord évalué numériquement les performances de l’approche « operator calculus algebra » introduit par R. Schott et S. Staples qui définit un algorithme efficace permettant de trouver tous les chemins satisfaisant les contraintes multiples dans un graphe , puis dérivé une version distribuée sur laquelle nous avons conçu un protocole de routage multi-métriques. Ces deux contributions ont été implémentées dans l’environnement Contiki et émulées/simulées sous Cooja (un logiciel permettant de simuler des protocoles des réseaux de capteurs) / In this thesis, we focus on routing protocols for Wireless Sensor Networks (WSNs). The main research problems in the domain of routing data packets in a multi-hop network are the optimisation of the energy and the routing under multi-criteria QoS constraints (e.g., energy, reliability, delay, …). To address these problems, this dissertation proposes two contributions. Firstly, an optimal probabilistic routing protocol which balances the usage of energy and secondly, a routing protocol which is able to simultaneously take into account multiple QoS metrics. In fact, for balancing the energy consumption between the multiple existing links, the existing probabilistic routing protocols assign a probability to each link, either in an empirical way or depending on proportional energy level of the path. We did not know what are the optimal probabilities which lead to the optimal network lifetime. Our first contribution proposes optimal probabilities by modeling and solving a linear programming problem. As for the multi-constrainted QoS routing problem, multiple metrics are defined by RPL (a standard of IETF) but the existing protocols chose paths either according to only one metric or using a single aggregated function with multiple metrics, but never all the metrics simultaneously. In this dissertation, we first evaluate the performance of the operator calculus algebra introduced by R. Schott and S. Staples which defines an efficient algorithm allowing to find all the paths which satisfy the multiple constraints in a graph, and secondly we proposed a distributed version of this algorithm based on which a routing protocol has been designed. Both contributions are implemented in Contiki environment and simulated/emulated under Cooja (a software designed for simulating protocols of WSNs)