La virtualisation apparaît comme étant une solution clé pour révolutionner l'architecture ossifiée des réseaux comme Internet. En ajoutant une couche d'abstraction au-dessus du matériel, la virtualisation permet de gérer et de configurer des réseaux virtuels indépendamment les uns des autres. La flexibilité qui en résulte donne à l'opérateur d'un réseau virtuel la possibilité de configurer la topologie, et de modifier les piles protocolaires. Jusqu'à présent, la virtualisation du réseau a été implémentée dans des plateformes de test ou de recherche, pour permettre l'expérimentation avec les protocoles de routage. Dans le but d'introduire la virtualisation dans les réseaux de production comme ceux de l'Internet, plusieurs nouveaux défis apparaissent, dont en particulier la performance et le partage des ressources de commutation et de routage. Ces deux questions sont particulièrement pertinentes, lorsque le plan de données du réseau lui-même est virtualisé, pour offrir un maximum d'isolation et de configurabilité. Pour cela, nous évaluons et analysons d'abord l'impact de la virtualisation sur la performance des routeurs virtuels logiciels. Puis, dans le but de pouvoir virtualiser le plan de données dans des réseaux de production, nous proposons une architecture matérielle de commutateur virtualisé, permettant le partage différencié des ressources tels que les ports et les tampons mémoire. D'autre part, nous examinons les possibles applications des réseaux virtuels et proposons un service de réseaux virtuels à la demande, avec un routage configurable, et des bandes passantes contrôlées, Nous appliquons et évaluons ce service dans le contexte d'infrastructures virtuelles. / Virtualization appears as a key solution to revolutionize the architecture of ossified networks, such as the Internet. By adding a layer of abstraction on top of the actual hardware, virtual networks can be managed and configured flexibly and independently. The flexibility introduced into the network provides the operator with options for topology reconfiguration, besides allowing it to play with the software stacks and protocols. Today, network virtualization has been realized in research testbeds, allowing researchers to experiment with routing. Introducing virtualization in a production network such as those of the Internet raises several challenges, in particular the performance and the sharing of the routing and switching resources. These are in particular relevant, when the network data plane is virtualized, for maximum isolation and configurability in virtual networks. Therefore, we first evaluate and analyze the impact of virtualization on the performance of virtual software routers. Then, for being able to virtualize the data plane in production networks, we propose a hardware architecture of a virtualized switch, enabling the differentiated sharing of resources such as the ports and the memory buffers. Moreover, we examine the possible applications of virtual networks and propose a service for virtual networks on demand with configurable routing and controlled bandwidth. We apply and evaluate this service in the context of virtual infrastructures.

With IPv4 addresses running out there is a need for IPv6 compatible routers. This study aims to find open source routers that have support for IPv6 and compare it in terms of performance to IPv4 to see if there are any differences in performance. In addition to this the chosen routers have also been evaluated in terms of security and other desired features. An experiment and a theoretical study evaluating this was carried out to help companies and individuals wanting to use IPv6 make choices in what open source router to use. Different performance factors were taken in to consideration as well as security features. There were no significant differences between IPv6 and IPv4 with IPv4 slightly beating IPv6. Between the routers there were some differences with the VyOS router outperforming pfSense in terms of throughput but pfSense had lower latency values. Depending on the requirements for a specific network environment the results of this study could be used to pick an IPv6-enabled open source router distribution.

As the performance of PCs is increasing it is of great interest to use these cheap devices as routers,which traditionally consisted of more expensive and customized hardware for that purpose. Thesoftware was also traditionally proprietary and thereby costly, but as the open source communityhas grown there have been development of open source solutions that can perform the task ofacting as a router. However as there are so many solutions out there, it can be hard for the potentialusers to choose which particular solution to use, without having to put in too much work intogetting a fully functional router solution. This study achieved this purpose by benchmarking themost popular open source software routers, in terms of performance and scalability as well asproviding a brief analysis of their basic security features. The routers that were studied wasClearOS, Untangle NG Firewall and IPFire, and after the study was complete IPFire was consideredthe superior with ClearOS as the second and Untangle as third and last.

Wireless sensor networks are battery-powered ad-hoc networks in which sensor nodes that are scattered over a region connect to each other and form multi-hop networks. These nodes are equipped with sensors such as temperature sensors, pressure sensors, and light sensors and can be queried to get the corresponding values for analysis. However, since they are battery operated, care has to be taken so that these nodes use energy efficiently. One of the areas in sensor networks where an energy analysis can be done is routing. This work explores grid-based coordinated routing in wireless sensor networks and compares the energy available in the network over time for different grid sizes.

Trust plays an important role in our daily life, both implicitly and explicitly. Our decisions are based on our estimation of how trustworthy a person is or how reliable a service is. Consequently, there has been a rise in trust systems that model human trust in a virtual or computing environment. These trust systems or trust models help to bridge the gap of human feelings and intuition in an unfamiliar environment. Trust models collect information regarding the participants' activities and give a trust rating based on observed activities. In a network environment, a plethora of network devices are in constant communication as data packets are transported from source to destination. The autonomous nature of network environments and devices make it difficult to monitor the services and devices from a central point. Security mechanisms, such as IPSec, exist in routing protocols to safeguard network packets travelling in a network, however routing devices that act as service providers are not protected by malicious attacks. For example, an attack aimed at the routing architecture of a network involves a routing device advertising itself as another routing device in order to divert network traffic away from its intended destination. This dissertation investigates trust models in network environments as a possible approach to predict and ultimately eliminate at- tacks on routing devices. To accomplish this, the role of routing devices as service providers and requesters must be stated explicitly. Activities on a routing device must be collected and used to determine the trust level of the routing device. This dissertation presents the TSONE - Trust in Service-Oriented Net- work Environment - model. The model incorporates traditional service- oriented architecture (SOA) principles to define a service-oriented network environment. Services in this environment are then defined. Furthermore the characteristics of this environment are adapted from SOA principles. An approach is defined to collect and measure activities on routing devices. This is later used to determine the trust level of the routing device. Finally, a pro- to type illustrates that incorporation of trust models is a possible option in assessing availability and reliability of routing devices. / Dissertation (MSc)--University of Pretoria, 2011. / Computer Science / unrestricted

Home routers are common in every household that has some kind of Internet connectivity. These embedded devices are running services such as web, file and DHCP server. Even though they have the same security issues as regular computers, they do no run protection software such as anti-virus and they are not updated. Moreover, the importance of these devices is misjudged; all network traffic is passing through them and they control the DNS of the network while, in most cases, they are on-line around the clock. When more and more non-Internet features are implemented into home routers, such as Voice over IP and network storage, their role becomes more special and many security concerns are raising. In this thesis, we investigate the issues resulting from this special role; the importance for these devices to be secure, the attacking vector and how the devices can be compromised to be part of a large home router botnet. We conclude by proposing ways to make the current implementation more secure, suggesting ways to protect routers from botnets without user interaction, that is from the ISP, while respecting the privacy of the end user and we identify what future work needs to be done. / Router är vanliga i hem som har någon slags Internet anslutning. De här inbyggda enheter kör tjänster som t.ex. web, file och DHCP basenheter. Fastän de har samma säkerhetsfrågor som vanliga datorer, så kan de inte använda säkerhets mjukvara som t.ex anti-virus och de är inte uppdaterade. Dessutom har betydelsen av de här apparaterna blivit felbedömmat; hela nätverket passerar genom dem och de kontrolerar nätverkets DNS medan, i de flesta fall, de är on-line dygnet runt. Men, när mer och mer icke-Internet lockvaror fars in i routern, som t.ex Voice över IP och nätverkslagring, blir deras roll viktigare och oron för säkerheten växer. I den här avhandlingen utforskars problemen och frågorna som efterföljer deras speciella roll, hur viktigt det är att de här apparaterna är skyddade, (the attacking vector) och hur de här apparaterna kan bli jämkningad för att bli en del av ett stort router botnet. Vi avsluter med att lägga fram sätt att göra det nuvarande verktyget mer skyddat, föreslå sätt att skydda routern från botnet utan användarinteraktion, som kommer från ISP, medan man respekterar det andra användarens privtaliv och markera vad som behövs ändras i framtiden.

Wireless networks have become increasingly popular in recent years. There are two variations of mobile wireless networks: infrastructure mobile networks and infrastructureless mobile networks. The latter are also known as mobile ad hoc network (MANET). MANETs have no fixed routers. Instead, mobile nodes function as relay nodes or routers, which discover and maintain communication connections between source nodes and destination nodes for various data transmission sessions. In other words, an MANET is a self-organizing multi-hop wireless network in which all nodes within a given geographical area participate in the routing and data forwarding process. Such networks are scalable and self-healing. They support mobile applications where an infrastructure is either not available (e.g., rescue operations and underground networks) or not desirable (e.g., harsh industrial environments). In many ad hoc networks such as vehicular networks, links among nodes change constantly and rapidly due to high node speed. Maintaining communication links of an established communication path that extends between source and destination nodes is a significant challenge in mobile ad hoc networks due to movement of the mobile nodes. In particular, such communication links are often broken under a high mobility environment. Communication links can also be broken by obstacles such as buildings in a street environment that block radio signal. In a street environment, obstacles and fast moving nodes result in a very short window of communication between nodes on different streets. Although a new communication route can be established when a break in the communication path occurs, repeatedly reestablishing new routes incurs delay and substantial overhead. To address this iv limitation, we introduce the Virtual Router abstraction in this dissertation. A virtual router is a dynamically-created logical router that is associated with a particular geographical area. Its routing functionality is provided by the physical nodes (i.e., mobile devices) currently within the geographical region served by the virtual router. These physical nodes take turns in forwarding data packets for the virtual router. In this environment, data packets are transmitted from a source node to a destination node over a series of virtual routers. Since virtual routers do not move, this scheme is much less susceptible to node mobility. There can be two virtual router approaches: Static Virtual Router (SVR) and Dynamic Virtual Router (DVR). In SVR, the virtual routers are predetermined and shared by all communication sessions over time. This scheme requires each mobile node to have a map of the virtual routers, and use a global positioning system (GPS) to determine if the node is within the geographical region of a given router. DVR is different from SVR with the following distinctions: (1) virtual routers are dynamically created for each communication sessions as needed, and deprecated after their use; (2) mobile nodes do not need to have a GPS; and (3) mobile nodes do not need to know whereabouts of the virtual routers. In this dissertation, we apply Virtual Router approach to address mobility challenges in routing data. We first propose a data routing protocol that uses SVR to overcome the extreme fast topology change in a street environment. We then propose a routing protocol that does not require node locations by adapting a DVR approach. We also explore how the Virtual Router Approach can reduce the overhead associated with initial route or location requests used by many existing routing protocols to find a destination. An initial request for a destination is expensive v because all the nodes need to be reached to locate the destination. We propose two broadcast protocols; one in an open terrain environment and the other in a street environment. Both broadcast protocols apply SVR. We provide simulation results to demonstrate the effectiveness of the proposed protocols in handling high mobility. They show Virtual Router approach can achieve several times better performance than traditional routing and broadcast approach based on physical routers (i.e., relay nodes)

Seven to ten percent of the energy used globally goes towards powering information and communications technology (ICT): the global data- and telecommunications network, the private and commercial datacenters it supports, and the 19 billion electronic devices around the globe it interconnects, through which we communicate, and access and produce information. As bandwidth and data rates increase, so does the volume of traffic, as well as the absolute amount of new information digitized and uploaded onto the Net and into the cloud each second. Words like gigabit and terabyte were needless fifteen years ago in the public arena; now, they are common phrases. As people use their networked devices to do more, to access more, to send more, and to connect more, they use more energy--not only in their own devices, but also throughout the ICT. While there are many endeavors focused on individual low-power devices, few are examining broad strategies that cross the many boundaries of separate concerns within the ICT; also, few are assessing the impact of specific strategies on the global energy supply: at a global scale. This work examines the energy savings of several such strategies; it also assesses their efficacy in reducing energy consumption, both within specific networks and within the larger ICT. All of these strategies save energy by reducing the work done by the system as a whole on behalf of a single user, often by exploiting commonalities among what many users around the globe are also doing to amortize the costs. / Ph. D.

Internet of Things (IoT) is the idea that every device around us is connected and these devices continually collect and communicate data for analysis at a large scale in order to enable better end user experience, resource utilization and device performance. Therefore, data is central to the concept of IoT and the amount being collected is growing at an unprecedented rate. Current networking systems and hardware are not fully equipped to handle influx of data at this scale which is a serious problem because it can lead to erroneous interpretation of the data resulting in low resource utilization and bad end user experience defeating the purpose of IoT. This thesis aims at improving data transportation for IoT. In IoT systems, devices are connected to one or more cloud services over the internet via an access link. The cloud processes the data sent by the devices and sends back appropriate instructions. Hence, the performance of the two ends of the network ie the access networks and datacenter network, directly impacts the performance of IoT. The first portion of the our research targets improvement of the access networks by improving access link (router) design. Among the important design aspects of routers is the size of their output buffer queue. %Selecting an appropriate size of this buffer is crucial because it impacts two key metrics of an IoT system: 1) access link utilization and 2) latency. We have developed a probabilistic model to calculate the size of the output buffer that ensures high link utilization and low latency for packets. We have eliminated limiting assumptions of prior art that do not hold true for IoT. Our results show that for TCP only traffic, buffer size calculated by the state of the art schemes results in at least 60% higher queuing delay compared to our scheme while achieving almost similar access link utilization, loss-rate, and goodput. For UDP only traffic, our scheme achieves at least 91% link utilization with very low queuing delays and aggregate goodput that is approx. 90% of link capacity. Finally, for mixed traffic scenarios our scheme achieves higher link utilization than TCP only and UDP only scenarios as well as low delays, low loss-rates and aggregate goodput that is approx 94% of link capacity. The second portion of the thesis focuses on datacenter networks. Applications that control IoT devices reside here. Performance of these applications is affected by the choice of TCP used for data communication between Virtual Machines (VM). However, cloud users have little to no knowledge about the network between the VMs and hence, lack a systematic method to select a TCP variant. We have focused on characterizing TCP Cubic, Reno, Vegas and DCTCP from the perspective of cloud tenants while treating the network as a black box. We have conducted experiments on the transport layer and the application layer. The observations from our transport layer experiments show TCP Vegas outperforms the other variants in terms of throughput, RTT, and stability. Application layer experiments show that Vegas has the worst response time while all other variants perform similarly. The results also show that different inter-request delay distributions have no effect on the throughput, RTT, or response time. / Master of Science / Internet of Things (IoT) is the idea that every electronic device around us, like watches, thermostats and even refrigerators, is connected to one another and these devices continually collect and communicate data. This data is analyzed at a large scale in order to enable better user experience and improve the utilization and performance of the devices. Therefore, data is central to the concept of IoT and because of the unprecedented increase in the number of connected devices, the amount being collected is growing at an unprecedented rate. Current computer networks over which the data is transported, are not fully equipped to handle influx of data at this scale. This is a serious problem because it can lead to erroneous analysis of the data, resulting in low device utilization and bad user experience, hence, defeating the purpose of IoT. This thesis aims at improving data transportation for IoT by improving different components involved in computer networks. In IoT systems, devices are connected to cloud computing services over the internet through a router. The router acts a gateway to send data to and receive data from the cloud services. The cloud services act as the brain of IoT i.e. they process the data sent by the devices and send back appropriate instructions for the devices to perform. Hence, the performance of the two ends of the network i.e. routers in the access networks and cloud services in datacenter network, directly impacts the performance of IoT. The first portion of our research targets the design of routers. Among the important design aspects of routers is their size of their output buffer queue which holds the data packets to be sent out. We have developed a novel probabilistic model to calculate the size of the output buffer that ensures that the link utilization stays high and the latency of the IoT devices stays low, ensuring good performance. Results show that that our scheme outperforms state-of-the-art schemes for TCP only traffic and shows very favorable results for UDP only and mixed traffic scenarios. The second portion of the thesis focuses on improving application service performance in datacenter networks. Applications that control IoT devices reside in the cloud and their performance is directly affected by the protocol chosen to send data between different machines. However, cloud users have almost no knowledge about the configuration of the network between the machines allotted to them in the cloud. Hence, they lack a systematic method to select a protocol variant that is suitable for their application. We have focused on characterizing different protocols: TCP Cubic, Reno, Vegas and DCTCP from the perspective of cloud tenants while treating the network as a black-box (unknown). We have provided in depth analysis and insights into the throughput and latency behaviors which should help the cloud tenants make a more informed choice of TCP congestion control.

Thesis (MSc)--Stellenbosch University, 2008. / ENGLISH ABSTRACT: Traffic Engineering (TE) is intended to be used in next generation IP networks to optimize the usage of network resources by effecting QoS agreements between the traffic offered to the network and the available network resources. TE is currently performed by the IP community using three methods including (1) IGP TE using connectionless routing optimization (2) MPLS TE using connection-oriented routing optimization and (3) Hybrid TE combining IGP TE with MPLS TE. MPLS has won the battle of the core of the Internet and is making its way into metro, access and even some private networks. However, emerging provider practices are revealing the relevance of using IGP TE in hybrid TE models where IGP TE is combined with MPLS TE to optimize IP routing. This is done by either optimizing IGP routing while setting a few number of MPLS tunnels in the network or optimizing the management of MPLS tunnels to allow growth for the IGP traffic or optimizing both IGP and MPLS routing in a hybrid IGP+MPLS setting. The focus of this thesis is on IGP TE using heuristic algorithms borrowed from the computational intelligence research field. We present four classes of algorithms for Maximum Link Utilization (MLU) minimization. These include Genetic Algorithm (GA), Gene Expression Programming (GEP), Ant Colony Optimization (ACO), and Simulated Annealing (SA). We use these algorithms to compute a set of optimal link weights to achieve IGP TE in different settings where a set of test networks representing Europe, USA, Africa and China are used. Using NS simulation, we compare the performance of these algorithms on the test networks with various traffic profiles. / AFRIKAANSE OPSOMMING: Verkeersingenieurswese (VI) is aangedui vir gebruik in volgende generasie IP netwerke vir die gebruiksoptimering van netwerkbronne deur die daarstelling van kwaliteit van diens ooreenkomste tussen die verkeersaanbod vir die netwerk en die beskikbare netwerkbronne. VI word huidiglik algemeen bewerkstellig deur drie metodes, insluitend (1) IGP VI gebruikmakend van verbindingslose roete-optimering, (2) MPLS VI gebruikmakend van verbindingsvaste roete-optimering en (3) hibriede VI wat IGP VI en MPLS VI kombineer. MPLS is die mees algemene, en word ook aangewend in metro, toegang en selfs sommige privaatnetwerke. Nuwe verskaffer-praktyke toon egter die relevansie van die gebruik van IGP VI in hibriede VI modelle, waar IGP VI gekombineer word met MPLS VI om IP roetering te optimeer. Dit word gedoen deur `of optimering van IGP roetering terwyl ’n paar MPLS tonnels in die netwerk gestel word, `of optimering van die bestuur van MPLS tonnels om toe te laat vir groei in die IGP verkeer `of die optimering van beide IGP en MPLS roetering in ’n hibriede IGP en MPLS situasie. Die fokus van hierdie tesis is op IGP VI gebruikmakend van heuristieke algoritmes wat ontleen word vanuit die berekeningsintelligensie navorsingsveld. Ons beskou vier klasse van algoritmes vir Maksimum Verbindingsgebruik (MVG) minimering. Dit sluit in genetiese algoritmes, geen-uitdrukkingsprogrammering, mierkoloniemaksimering and gesimuleerde temperoptimering. Ons gebruik hierdie algoritmes om ’n versameling optimale verbindingsgewigte te bereken om IGP VI te bereik in verskillende situasies, waar ’n versameling toetsnetwerke gebruik is wat Europa, VSA, Afrika en China verteenwoordig. Gebruikmakende van NS simulasie, vergelyk ons die werkverrigting van hierdie algoritmes op die toetsnetwerke, met verskillende verkeersprofiele.