Big data has received a great deal attention from many sectors, including academia, industry and government. The Hadoop framework has emerged for supporting its storage and analysis using the MapReduce programming module. However, this framework is a complex system that has more than 150 parameters and some of them can exert a considerable effect on the performance of a Hadoop job. The optimum tuning of the Hadoop parameters is a difficult task as well as being time consuming. In this thesis, an optimisation approach is presented to improve the performance of a Hadoop framework by setting the values of the Hadoop parameters automatically. Specifically, genetic programming is used to construct a fitness function that represents the interrelations among the Hadoop parameters. Then, a genetic algorithm is employed to search for the optimum or near the optimum values of the Hadoop parameters. A Hadoop cluster is configured on two severe at Brunel University London to evaluate the performance of the proposed optimisation approach. The experimental results show that the performance of a Hadoop MapReduce job for 20 GB on Word Count Application is improved by 69.63% and 30.31% when compared to the default settings and state of the art, respectively. Whilst on Tera sort application, it is improved by 73.39% and 55.93%. For better optimisation, SDN is also employed to improve the performance of a Hadoop job. The experimental results show that the performance of a Hadoop job in SDN network for 50 GB is improved by 32.8% when compared to traditional network. Whilst on Tera sort application, the improvement for 50 GB is on average 38.7%. An effective computing platform is also presented in this thesis to support solar irradiation data analytics. It is built based on RHIPE to provide fast analysis and calculation for solar irradiation datasets. The performance of RHIPE is compared with the R language in terms of accuracy, scalability and speedup. The speed up of RHIPE is evaluated by Gustafson's Law, which is revised to enhance the performance of the parallel computation on intensive irradiation data sets in a cluster computing environment like Hadoop. The performance of the proposed work is evaluated using a Hadoop cluster based on the Microsoft azure cloud and the experimental results show that RHIPE provides considerable improvements over the R language. Finally, an effective routing algorithm based on SDN to improve the performance of a Hadoop job in a large scale cluster in a data centre network is presented. The proposed algorithm is used to improve the performance of a Hadoop job during the shuffle phase by allocating efficient paths for each shuffling flow, according to the network resources demand of each flow as well as their size and number. Furthermore, it is also employed to allocate alternative paths for each shuffling flow in the case of any link crashing or failure. This algorithm is evaluated by two network topologies, namely, fat tree and leaf-spine, built by EstiNet emulator software. The experimental results show that the proposed approach improves the performance of a Hadoop job in a data centre network.

Throughout the evolution of communication networks, users have consistently been demanding additional data and coverage. Future 6G networks seek to enable a seamless cyber-physical world through interconnected and integrated connectivity. Hereafter, to address these challenges and ensure the adaptability of future wireless networks, new technologies emerge. Relaying presents an attractive alternative, as it can be a cost-efficient deployment of highly dense networks, and it can enhance the performance of mobile networks in terms of both coverage and capacity. In addition, to meet the demanding Key Performance Indicators (KPI) of user experience, the relaying can be achieved via a User Equipment (UE) through UE-to-Network relaying as an alternative to conventional small-cell deployment of relay stations. The purpose of this project is to assess the impact of UE-based relaying policies. A comparative analysis is conducted, examining these schemes and a macro-only deployment. The study begins by conducting an analysis of the Third Generation Partnership Project (3GPP) urban macro scenario and then extends to include the real-world deployment scenario in London. Results have validated that UE relaying techniques help improve cell edge capacity and coverage compared to macro-only deployments. User throughput is enhanced up to three times in Downlink (DL) and twelve times in Uplink (UL) in the 3GPP urban macro deployment. While user throughput is improved up to ten times in DL and thirteen times in UL on the London map deployment. / Under utvecklingen av kommunikationsnätverk har användarna konsekvent efterfrågat ytterligare data och täckning. Framtida 6G-nätverk strävar efter att möjliggöra en sömlös cyber-fysisk värld genom sammanlänkad och integrerad anslutning. För att möta dessa utmaningar och säkerställa anpassningsbarheten hos framtida trådlösa nätverk framträder nya teknologier. Reläering utgör ett attraktivt alternativ eftersom det kan vara en kostnadseffektiv implementering av högt täta nätverk och signifikant förbättra prestandan hos mobila nätverk både vad gäller täckning och kapacitet. Dessutom kan reläeringen användas för att möta de utmanande behoven av användarupplevelse genom att användarutrustning (UE) används för reläeringen, vilket utgör ett alternativ till konventionell implementering av småceller för relästationer. Det primära fokuset för detta projekt är att bedöma påverkan av reläeringspolicyn baserad på UE. En jämförande analys genomförs där dessa metoder och enbart makroimplementering undersöks. Inledningsvis utförs studien i en urbant makroscen från Third Generation Partnership Project (3GPP), vilket utgör en grund för att utöka metodologin till en verklig implementeringsscen i London. Resultaten har visat att UE-reläeringstekniker bidrar till att förbättra kapaciteten och täckningen i cellens utkanter jämfört med enbart makroimplementering. Användarnas genomströmning ökar upp till tre gånger i nerlänken (DL) och tolv gånger i upplänken (UL) i 3GPP: s urbana makroimplementering. Samtidigt förbättras användarnas genomströmning upp till tio gånger (DL) och tretton gånger (UL) i Londonkartaimplementationen.

Delay is known to be a critical performance metric for various real-world routing applications including multimedia communication and freight delivery. Provisioning delay-minimal (or at least delay-bounded) routing services for all traffic of an application is highly important. As a basic paradigm of networking, multi-path routing has been proven to be able to obtain lower delay performance than the single-path routing, since traffic congestions can be avoided. However, to our best knowledge, (i) many of existing delay-aware multi-path routing studies only consider the aggregate traffic delay. Considering that even the solution achieving the optimal aggregate traffic delay has a possibly unbounded delay performance for certain individual traffic unit, those studies may be insufficient in practice; besides, (ii) most existing studies which optimize or bound delays of all traffic are best-effort, where the achieved solutions have no theoretical performance guarantee. In this dissertation, we study four delay-aware multi-path routing problems, with the delay performances of all traffic taken into account. Three of them are in communication and one of them is in transportation. Note that our study differ from all related ones as we are the first to study the four fundamental problems to our best knowledge. Although we prove that our studied problems are all NP-hard, we design approximation algorithms with theoretical performance guarantee for solving each of them. To be specific, we claim the following contributions. Minimize maximum delay and average delay. First, we consider a single-unicast setting where in a multi-hop network a sender requires to use multiple paths to stream a flow at a fixed rate to a receiver. Two important delay metrics are the average sender-to-receiver delay and the maximum sender-to-receiver delay. Existing results say that the two delay metrics of a flow cannot be both within bounded-ratio gaps to the optimal. In comparison, we design three different flow solutions, each of which can minimize the two delay metrics simultaneously within a $(1/epsilon)$-ratio gap to the optimal, at a cost of only delivering $(1-epsilon)$-fraction of the flow, for any user-defined $epsilonin(0,1)$. The gap $(1/epsilon)$ is proven to be at least near-tight, and we further show that our solutions can be extended to the multiple-unicast setting. Minimize Age-of-Information (AoI). Second, we consider a single-unicast setting where in a multi-hop network a sender requires to use multiple paths to periodically send a batch of data to a receiver. We study a newly proposed delay-sensitive networking performance metric, AoI, defined as the elapsed time since the generation of the last received data. We consider the problem of minimizing AoI subject to throughput requirements, which we prove is NP-hard. We note that our AoI problem differs from existing ones in that we are the first to consider the batch generation of data and multi-path communication. We develop both an optimal algorithm with a pseudo-polynomial time complexity and an approximation framework with a polynomial time complexity. Our framework can build upon any polynomial-time $alpha$-approximation algorithm of the maximum delay minimization problem, to construct an $(alpha+c)$-approximate solution for minimizing AoI. Here $c$ is a constant dependent on throughput requirements. Maximize network utility. Third, we consider a multiple-unicast setting where in a multi-hop network there exist many network users. Each user requires a sender to use multiple paths to stream a flow to a receiver, incurring an utility that is a function of the experienced maximum delay or the achieved throughput. Our objective is to maximize the aggregate utility of all users under throughput requirements and maximum delay constraints. We observe that it is NP-complete either to construct an optimal solution under relaxed maximum delay constraints or relaxed throughput requirements, or to figure out a feasible solution with all constraints satisfied. Hence it is non-trivial even to obtain approximate solutions satisfying relaxed constraints in a polynomial time. We develop a polynomial-time approximation algorithm. Our algorithm obtains solutions with constant approximation ratios under realistic conditions, at the cost of violating constraints by up to constant-ratios. Minimize fuel consumption for a heavy truck to timely fulfill multiple transportation tasks. Finally, we consider a common truck operation scenario where a truck is driving in a national highway network to fulfill multiple transportation tasks in order. We study an NP-hard timely eco-routing problem of minimizing total fuel consumption under task pickup and delivery time window constraints. We note that optimizing task execution times is a new challenging design space for saving fuel in our multi-task setting, and it differentiates our study from existing ones under the single-task setting. We design a fast and efficient heuristic. We characterize conditions under which the solution of our heuristic must be optimal, and further prove its optimality gap in case the conditions are not met. We simulate a heavy-duty truck driving across the US national highway system, and empirically observe that the fuel consumption achieved by our heuristic can be $22%$ less than that achieved by the fastest-/shortest- path baselines. Furthermore, the fuel saving of our heuristic as compared to the baselines is robust to the number of tasks. / Doctor of Philosophy / We consider a network modeled as a directed graph, where it takes time for data to traverse each link in the network. It models many critical applications both in the communication area and in the transportation field. For example, both the European education network and the US national highway network can be modeled as directed graphs. We consider a scenario where a source node is required to send multiple (a set of) data packets to a destination node through the network as fast as possible, possibly using multiple source-to-destination paths. In this dissertation we study four problems all of which try to figure out routing solutions to send the set of data packets, with an objective of minimizing experienced travel time or subject to travel time constraints. Although all of our four problems are NP-hard, we design approximation algorithms to solve them and obtain solutions with theoretically bounded gaps as compared to the optimal. The first three problems are in the communication area, and the last problem is in the transportation field. We claim the following specific contributions. Minimize maximum delay and average delay. First, we consider the setting of simultaneously minimizing the average travel time and the worst (largest) travel time of sending the set of data packets from source to destination. Existing results say that the two metrics of travel time cannot be minimized to be both within bounded-ratio gaps to the optimal. As a comparison, we design three different routing solutions, each of which can minimize the two metrics of travel time simultaneously within a constant bounded ratio-gap to the optimal, but at a cost of only delivering a portion of the data. Minimize Age-of-Information (AoI). Second, we consider the problem of minimizing a newly proposed travel-time-sensitive performance metric, i.e., AoI, which is the elapsed time since the generation of the last received data. Our AoI study differs from existing ones in that we are the first to consider a set of data and multi-path routing. We develop both an optimal algorithm with a pseudo-polynomial time complexity and an approximation framework with a polynomial time complexity. Maximize network utility. Third, we consider a more general setting with multiple source destination pairs. Each source incurs a utility that is a function of the experienced travel time or the achieved throughput to send data to its destination. Our objective is to maximize the aggregate utility under throughput requirements and travel time constraints. We develop a polynomial-time approximation algorithm, at the cost of violating constraints by up to constant-ratios. It is non-trivial to design such algorithms, as we prove that it is NPcomplete either to construct an optimal solution under relaxed delay constraints or relaxed throughput requirements, or to figure out a feasible solution with all constraints satisfied. Minimize fuel consumption for a heavy truck to timely fulfill multiple transportation tasks. Finally, we consider a truck and multiple transportation tasks in order, where each task requires the truck to pick up cargoes at a source timely, and deliver them to a destination timely. The need of coordinating task execution times is a new challenging design space for saving fuel in our multi-task setting, and it differentiates our study from existing ones under the single-task setting. We design an efficient heuristic. We characterize conditions under which the solution of our heuristic must be optimal, and further prove its performance gap as compared to the optimal in case the conditions are not met.

Wireless communication has seen a tremendous growth in the last decades. Continuing on this trend, wireless multi-hop networks  are nowadays used or planned for use in a multitude of contexts, spanning from Internet access at home to emergency situations. The Transmission Control Protocol (TCP) provides reliable and ordered delivery of a data and is used by major Internet applications such as web browsers, email clients and file transfer programs. TCP traffic is also the dominating traffic type on the Internet. However, TCP performs less than optimal in wireless multi-hop networks due to packet reordering, low link capacity, packet loss and variable delay. In this thesis, we develop novel proposals for enhancing the network and transport layer to improve TCP performance in wireless multi-hop networks. As initial studies, we experimentally evaluate the performance of different TCP variants, with and without mobile nodes. We further evaluate the impact of multi-path routing on TCP performance and propose packet aggregation combined with aggregation aware multi-path forwarding as a means to better utilize the available bandwidth. The last contribution is a novel extension to multi-path TCP to  enable single-homed hosts to fully utilize the network capacity. / <p>Opponent changed. Prof. C. Lindeman from the University of Leipzig was substituted by Prof. Zhang.</p>

Orientador: Nelson Luis Saldanha da Fonseca / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Computação / Made available in DSpace on 2018-08-27T12:19:41Z (GMT). No. of bitstreams: 1 Santi_Julianade_D.pdf: 2864937 bytes, checksum: 7526ed7e2e57bec4e7361a8c0f9f8b47 (MD5) Previous issue date: 2015 / Resumo: As redes ópticas com multiplexação por comprimento de onda (WDM) permitem a transmissão de grande volume de dados através de múltiplos canais com capacidade de transmissão de vários Gbps. Entretanto, as demandas por banda passante dos fluxos IPs são significativamente inferior à capacidade disponível em cada canal WDM. Para lidar com esta disparidade e utilizar de forma eficiente a banda disponível, é necessária a transmissão simultânea de vários fluxos em um caminho óptico, chamado de agregação de tráfego. Especificações de qualidade de serviço dos fluxos devem, também, ser consideradas nas decisões de agregação de tráfego. Ademais, aplicações emergentes podem demandar largura de banda superior à capacidade de um comprimento de onda, sendo necessário utilizar vários caminhos ópticos (roteamento multicaminho) para provisionar tais fluxos. Além disso, a expansão da infraestrutura e utilização das redes WDM têm elevado o consumo de energia, causando impactos econômicos e ambientais. Estas questões têm desafiado e motivado pesquisadores a encontrar alternativas para aprimorar as transmissões nas redes ópticas WDM, o que inclui a agregação de tráfego e o roteamento multicaminho. Nesta tese, abordam-se diversos problemas em agregação de tráfego e roteamento multicaminho em redes ópticas WDM. Foram desenvolvidos e validados algoritmos pelo menos tão eficientes quanto algoritmos existentes na literatura. Propõe-se um algoritmo de agregação de tráfego que considera a duração das conexões e a banda disponível. Para atender demandas superiores à capacidade de um comprimento de onda, desenvolveu-se um algoritmo que considera a duração do fluxo, divide-o em subfluxos e os transmite em múltiplos canais. Para este algoritmo, foi proposta uma versão aproximada visando reduzir o tempo de resolução do problema. Introduziu-se, também, um algoritmo que indica a postergação do momento de início da transmissão das conexões a fim de agregar lotes de conexões. Para reduzir o consumo de energia, foram desenvolvidas duas estratégias, de roteamento multicaminho e reroteamento, que levam em consideração o consumo de energia das operações envolvidas na transmissão da conexão / Abstract: The wavelength division multiplexing (WDM) optical networks allow the transmission of large volume of data through multiple channels with severals Gbps of transmission capacity. However, the demand for bandwidth of IP flows are significantly lower than the available capacity in each WDM channel. To address this disparity and make efficient use of the available bandwidth, it is necessary to transmit simultaneously multiple streams in lightpath, called traffic grooming. The quality of service specifications inherent to connections should also be considered in the traffic aggregation decisions. Moreover, emerging applications can request bandwidth greater than the capacity of a wavelength, which require several lightpaths (multipath routing) to establish such connections. In addition, infrastructure expansion and use of WDM networks have increased the energy consumption, leading to economic and environmental concerns. These issues have challenged and motivated researchers to find alternatives to enhance transmissions in WDM optical networks, which includes the traffic grooming and multipath routing. This thesis addresses several problems in traffic grooming and multipath routing in WDM optical networks. For each problem algorithms were developed and validated that are at least as efficient as existing algorithms in the literature. It was proposed a traffic grooming algorithm that considers the duration of connections and the available bandwidth along the path. In order to establish connections demanding bandwidth greater than the capacity of a wavelength, it was proposed an algorithm that considers the duration of a connection and divides this connection in to substreams and transmits them on multiple wavelengths. For this algorithm, it was proposed an approximate version to reduce the run time. Moreover, it was introduced an algorithm which postpones the time to establish the connections and aggregates batch connections. In order to reduce the energy consumption, two strategies, multipath routing and rerouting, were developed that take into account the energy consumption of each operation involved in the connection transmission / Doutorado / Ciência da Computação / Doutora em Ciência da Computação

This thesis deals with transmission of data over power-line. There is theoretically described PLC technology and its classification, properties and used modulation techniques. A substantial part is focused on the mathematical description of distribution network using two methods, with multipath propagation and ABCD matrix. These methods are mutually compared. Furthermore, they are examined depending on the transfer functions of the topology and capabilities for unknown topology. Calculations of transfer functions are implemented using Matlab. The results were then processed graphically and evaluated.

No description available.

當發生大規模地震或強烈颱風等大型天然災害，其災後72小時為人命搜救之黃金期。由歷來的大型災變中，可知行動通訊系統其實極為脆弱且不可靠，而通訊系統癱瘓將影響救災工作之成效。本論文中探討的應急通訊系統利用倖存之連通基地台和斷訊卻沒有損毀的基地台，以無線電互相連接成一個轉送拓樸以建構臨時性通訊系統，稱為應急蜂巢式行動通訊網路(Contingency Cellular Network，CCN)。 在災難發生後，災區通常有許多須要較高通話需求的關鍵區域，其通話需求遠高於輕度災區，建置CCN時必須優先保障其通訊需求，我們先前之研究所提出的樹狀轉送拓樸其結構較脆弱，若任何一個link斷訊失去轉送功能，則其節點以下的使用者通訊將受到影響，導致任何一個節點對外通訊能力非常脆弱，影響CCN之可用度。為了提升CCN之可用度，我們提出了多路徑的CCN網路拓樸解決方案，在本方案中，每個關鍵區域都有數條對外通訊的連線。 本論文以各基地台通訊範圍內的通訊需求人數與災區毀損程度，作為效益參數，在有限緊急修復資源下，將問題塑模為一個類似K-Maximum Spanning Tree問題的Length Bounded Disjoint K-Path Max-Profit Mesh問題，我們證明它屬於NP-Hard問題，並且提出快速且效能不差之啟發式演算法，可在緊急時建立應急蜂巢式行動網路的多路徑網路拓樸。本文以電腦模擬方式，進行實驗以驗證我們的模型之適切性，並評估多路徑拓樸可提升之CCN可用度，實驗結果可提供使用者依不同的CCN可用度及總救災效益需求，選擇所需之多路徑數量。 / When stricken by a catastrophic natural disaster, the golden 72 hours is very critical to life saving. However, communication systems including cellular networks often crashed due to various causes making big impact to the efficiency of disaster response. Our research proposes the Contingency Cellular Network (CCN) by connecting disconnected base stations together using wireless links to form an overlay Ad Hoc network over a disconnected cellular network. 　　In our previous study, we proposed a tree topology to construct CCN, which is vulnerable since a single link failure may have a big impact to the availability of CCN. This thesis proposes a multi-path topology to enhance the availability of CCN such that the selected critical areas will have redundant communication paths connecting to the core network and thus, have higher resiliency against link failure. We model the CCN Multi-path Network Topology Design problem into a combinatorial problem, called Length Bounded Disjoint K-Path Max-Profit Mesh Problem. We take the degree of emergency and the population of each stricken area as the priority measure as well as the amount of emergency recovery resources as the capacity constraint in the topology computation model. The problem is proven to be NP Hard. Therefore, we designed an efficient heuristic algorithm (HLBDK) to solve the problem when it is needed in urgent. Finally, we evaluated the proposed algorithm by simulation. The simulation results show that the average performance deviation of the proposed heuristic algorithm away from the optimal solutions is smaller than 7% in all cases. A significant improvement in the availability can be obtained by using multi-path topology at a reasonable performance degradation. Our research results provide users a fundamental base to determine their availability requirement at a countable performance degradation.

Un réseau sans fil multi-saut est un ensemble d’entités mobiles et/ou fixes formant un réseau dynamique temporaire avec ou sans l’aide de toute administration centralisée. Cette particularité rend le routage problématique en cas d’instabilité des éléments qui composent les communications non directes. Afin de palier ces problèmes, de nouvelles formes de routage sont utilisées comme le routage multi-chemin (MC). Le routage MC permet d’envoyer les données sur des chemins multiples et semble être une solution efficace pour ces réseaux. Le but de cette thèse est d’étudier les techniques de routage MC dans un contexte sans fil multi-saut en vue d’obtenir de meilleures performances. Nous avons choisi pour notre étude une extension MC du protocole OLSR, appelée MP-OLSR. Nous évaluons ses performances sous divers scénarios sous NS-2. Ces tests d’évaluation nous ont amenés à mettre en ´evidence deux problèmes dans MP-OLSR : la réactivité du protocole de routage MC suite à des ruptures de route et la stratégie de répartition des données sur les chemins multiples. Nous avons étudié la réactivité de tels mécanismes dans MP-OLSR. Nous avons proposé trois nouvelles techniques de réparation de pannes qui diminuent les temps de rétablissement d’une route et réduisent le taux de perte des flux transmis. Nous proposons aussi un mécanisme qui détecte la dégradation de la qualité des liens durant le transfert d’un trafic de données. Les informations déduites de ce mécanisme servent à adapter la proportion de trafic à affecter à chaque chemin selon les conditions réseaux. Cette nouvelle variante du protocole MP-OLSR est évaluée par simulation. / Wireless multi-hop networks consist of a collection of mobile and/or fixed nodes which dynamically exchange data with (or without) reliance on a (any) centralized administration. They are by definition self-organized. The frequent topological changes make multi-hop routing a crucial issue for these networks. To overcome these problems, new forms of routing schemes are used as the multipath routing (MP). MP routing uses multiple paths to send data and can be regarded as an effective solution for these networks. The purpose of this PhD thesis is to study the MP routing techniques in a wirelessmulti-hop context for better performance. We choose for our study a MP extension of OLSR, called MP-OLSR. We evaluate its performance under various scenarios in NS-2. These tests have led us to highlight two problems in MP-OLSR : the long recovery delays when facing network failure situations and the allocation strategy of data on multiple paths. We define and seek to evaluate the latency introduced by both protocols OLSR and MP-OLSR to find a new path after a link failure. We propose three new different recovery schemes and accordingly extend these original protocols in order to decrease theexpected latency and reduce the packet loss rate of transmitted flow. We also propose a mechanism which is able to detect the deterioration of the link quality during the transfer of data traffic. The information derived from this mechanism is used to adjust the proportion of traffic to be assigned to each path according to network conditions. This new version of MP-OLSR protocol is evaluated by simulation.

Innovations in optical communication are expected to transform the landscape of global communications, internet and datacenter networks. This dissertation investigates several important issues in optical communication such as fairness, throughput, blocking probability and differentiated quality of service (QoS). Novel algorithms and new approaches have been presented to improve the performance of optical circuit switching (OCS) and optical burst switching (OBS) for long haul, and datacenter networks. Extensive simulations tests have been conducted to evaluate the effectiveness of the proposed algorithms. These simulation tests were performed over a number of network topologies such as ring, mesh and U.S. Long-Haul, some high processing computing (HPC) topologies such as 2D and 6D mesh torus topologies and modern datacenter topologies such as FatTree and BCube. Two new schemes are proposed for long haul networks to improve throughput and hop count fairness in OBS networks. The idea is motivated by the observation that providing a slightly more priority to longer bursts over short bursts can significantly improve the throughput of the OBS networks without adversely affecting hop-count fairness. The results of extensive performance tests have shown that proposed schemes improve the throughput of optical OBS networks and enhance the hop-count fairness. Another contribution of this dissertation is the research work on developing routing and wavelength assignment schemes in multimode fiber networks. Two additional schemes for long haul networks are presented and evaluated over multimode fiber networks. First for alleviating the fairness problem in OBS networks using wavelength-division multiplexing as well as mode-division multiplexing while the second scheme for achieving higher throughput without sacrificing hop count fairness. We have also shown the significant benefits of using both mode division multiplexing and wavelength division multiplexing in real-life short-distance optical networks such as the optical circuit switching networks used in the hybrid electronic-optical switching architectures for datacenters. We evaluated four mode and wavelength assignment heuristics and compared their throughput performance. We also included preliminary results of impact of the cascaded mode conversion constraint on network throughput. Datacenter and high performance computing networks share a number of common performance goals. Another highly efficient adaptive mode wavelength- routing algorithm is presented over OBS networks to improve throughput of these networks. The effectiveness of the proposed model has been validated by extensive simulation results. In order to optimize bandwidth and maximize throughput of datacenters, an extension of TCP called multipath-TCP (MPTCP) has been evaluated over an OBS network using dense interconnect datacenter topologies. We have proposed a service differentiation scheme using MPTCP over OBS for datacenter traffic. The scheme is evaluated over mixed workload traffic model of datacenters and is shown to provide tangible service differentiation between flows of different priority levels. An adaptive QoS differentiation architecture is proposed for software defined optical datacenter networks using MPTCP over OBS. This scheme prioritizes flows based on current network state.