Thesis (MSc)--Stellenbosch University, 2002. / ENGLISH ABSTRACT: The Internet is evolving into a commercial platform requiring enhanced protocols and an expanded physical infrastructure allowing a better delivery from IP. Multi-protocol Label Switching (MPLS) is a technology enabling traffic engineering and virtual private network (VPN) provisioning. MPLS achieves traffic engineering by carrying the traffic over virtual connections called Label Switched Paths (LSPs) which are engineered based on QoS requirements such as delay, jitter and packet loss minimization or throughput maximization. This thesis proposes path finding and traffic distribution methods to be deployed in MPLS networks for traffic engineering LSPs. A flow optimization model based on a pre-planned routing approach separating path finding and traffic distribution is presented. This model is augmented by a threshold routing approach which routes the traffic based on thresholds expressing the maximum load level reached by network links. This routing approach moves the traffic away from thresholdmarked links to achieve low-utilized links/paths. The performance and routing capabilities of these methods are evaluated through designed software. A routing architecture implementing a two-layer signalling model for MPLS network is proposed and evaluated through simulation. v / AFRIKAANSE OPSOMMING:Die verandering van die Internet in 'n kommersiele platform met verbeterde protokolle en 'n uitgebreide fisieke infrastruktuur stel die internetprotokol (IP) in staat tot beter lewering. Multiprotokol- etiketskakeling (MPLS), is 'n tegnologie vir die voorsiening van televerkeerbeheer en virtuele privaatnetwerke (VPN). MPLS verskaf televerkeerbeheer deur die verkeer te dra oar virtuele konneksies, wat bekend staan as etiketgeskakelde paaie, waarvan die ontwerp gebaseer is op vereistes vir diensgehalte soos vertraging, ritteling en die minimering van pakketverlies of maksimering van deurvoer. Hierdie tesis stel nuwe padvind- en verkeerdistribusiemetodes voor wat aangewend word in MPLSnetwerke om etiketgeskakelde paaie te beheer. 'n Model vir vloei-optimering-gebaseer op voorafbeplande roetering wat padvinding en verkeerdistribusie skei-word aangebied. Hierdie model word uitgebrei deur 'n benadering van drempelroetering wat die verkeer roeteer en gebaseer is op drempels wat die maksimum ladingsvlak voorstel wat bereik kan word deur netwerkskakels. Hierdie roeteringsbenadering skuif die verkeer weg van drempelgemerkte skakels en bereik daardeur laaggebruikte skakelsjpaaie. Die prestasie en roeteringsvaardigheid van hierdie metodes word gevalueer deur selfontwikkelde programmatuur. 'n Argitektuur vir roetering wat 'n dubbellaagseinmodel implementeer vir 'n MPLS-netwerk, word aangebied en gevalueer met simulasie.

Thesis (MSc)--Stellenbosch University, 2003. / ENGLISH ABSTRACT: The Internet has experienced tremendous growth in the last three decades and has emerged as a platform to carryall forms of communications including voice, video and data. Along with this growth came the urgency for quality of service (QoS) controls in IP networks as different types of traffics have different service requirements. Although the IP protocol is able to scale to very large networks, it does not provide sufficient functionality for traffic engineering in order to enable QoS control. Multi-protocol label switching (MPLS) is a new routing technology that enhances IP with some QoS concepts from ATM and uses relatively simple packet forwarding mechanisms. MPLS has the ability to perform traffic engineering and QoS control by routing traffic flowson virtual connections called label switched paths (LSPs) which are assigned capacity. A large portion of the traffic carried on the Internet consists of data traffic in the form of TCP traffic. This thesis investigates several TCP models to find the ones most suitable to represent TCP traffic in MPLS networks. The models consist of three types. The first type models a single TCP source and the second type models a fixed number of TCP sources. The third type models an infinite number of TCP sources. The models were evaluated by comparing their throughput predictions and results obtained from simulation experiments that were done with the widely-used simulator ns. We also present a simple derivation of the 1/,;e law for the TCP congestion window size where e is the packet loss probability. / AFRIKAANSE OPSOMMING:In die afgelope drie dekades het die Internet beduidende groei ervaar, soveel so dat dit ontluik het as 'n medium om alle tipes van moderne kommunikasies te hanteer insluitend telefoon, video en data. Hierdie groei het gepaard gegaan met die behoefte na diensvlak (QoS) meganismes in IP netwerke aangesien verskillende tipe kommunikasies verskillende diens vereistes het. Alhoewel die IP protokol skalleerbaar is tot baie groot netwerke, voorsien dit nie voldoende funksionaliteit om QoS beheer toe te pas nie. "Multi-protocol label switching" (MPLS) is 'n nuwe roeterings tegnologie wat IP aanvul met QoS konsepte van ATM en dit maak gebruik van relatief eenvoudige pakkie versendings-meganismes. MPLS het die vermoe om netwerk-verkeer reeling en QoS beheer toe te pas deur verkeers-strome te roeteer op virtuele roetes genaamd "label switched paths" (LSPs) aan wie kapasiteit toegeken is. 'n Beduidende gedeelte van Internet-verkeer bestaan uit TCP-verkeer. Hierdie tesis ondersoek verskillende modelle van TCP om die te vind wat die mees geskik is om TCP verkeer in MPLS netwerke te verteenwoordig. Drie tipes modelle is ondersoek. Die eerste tipe moduleer 'n enkele TCP verkeersbron en die tweede tipe moduleer 'n vasgestelde aantal TCP verkeersbronne. Die derde tipe moduleer 'n oneindige aantal verkeersbronne. Die modelle is geevalueer deur hul voorspellings van die tempo van data transmissie te vergelyk met resultate van simulasies. Die simulasies is gedoen met die veelgebruikte simulator ns. Hierdie tesis bevat ook 'n eenvoudige afleiding vir die 1/,;e wet vir die TCP oorlading venster grootte met e die verlies waarskeinlikheid van 'n netwerk pakkie.

Approved for public release, distribution is unlimited / This thesis studies and discusses the development of the API, called the persistency API, for supporting the persistent data sessions. Without persistent session support, network applications often need to be restarted from the beginning when intermittent physical connection loss happens. Application programmers can use the persistency API to achieve the service continuity. The persistency API provides the interface that allows a program to continue retrieve data from the point the connection is lost after the physical connection is restored. The focus of this thesis is to develop a generalized persistency API that supports various types of applications. This thesis studies the persistent session support for two types of transport protocols, TCP and UDP, which are used by major network applications. An application that performs text file and video file transfer is implemented to demonstrate the persistent data transfer sessions for TCP and UDP, respectively. The study shows that the proposed APIs can support the data transfer continuity in the reconnection process. / Captain, Royal Thai Army

The IP Multimedia Subsystem (IMS) has gone from just a step in the evolution of the GSM cellular architecture control core, to being the de-facto framework for Next Generation Network (NGN) implementations and deployments by operators world-wide, not only cellular mobile communications operators, but also fixed line, cable television, and alternative operators. With this transition from standards documents to the real world, engineers in these new multimedia communications companies need to face the task of making these new networks secure against threats and real attacks that were not a part of the previous generation of networks. We present the IMS and other competing frameworks, we analyze the security issues, we present the topic of Security Patterns, we introduce several new patterns, including the basis for a Generic Network pattern, and we apply these concepts to designing a security architecture for a fictitious 3G operator using IMS for the control core. / by Jose M. Ortiz-Villajos. / Thesis (M.S.C.S.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.

The Transmission Control Protocol (TCP) is one of the core protocols of the Internet protocol suite. In the wired network, TCP performs remarkably well due to its scalability and distributed end-to-end congestion control algorithms. However, many studies have shown that the unmodified standard TCP performs poorly in networks with large bandwidth-delay products and/or lossy wireless links. In this thesis, we analyze the problems TCP exhibits in the wireless communication and develop TCP congestion control algorithm for mobile applications. We show that the optimal TCP congestion control and link scheduling scheme amounts to window-control oriented implicit primaldual solvers for underlying network utility maximization. Based on this idea, we used a scalable congestion control algorithm called QUeueIng-Control (QUIC) TCP where it utilizes queueing-delay based MaxWeight-type scheduler for wireless links developed in [34]. Simulation and test results are provided to evaluate the proposed schemes in practical networks. / by Gee Won Han. / Thesis (M.S.C.S.)--Florida Atlantic University, 2013. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

The Transmission Control Protocol (TCP) is one of the core protocols of the Internet protocol suite, which is used by major Internet applications such as World Wide Web, email, remote administration and file transfer. TCP implements scalable and distributed end-to-end congestion control algorithms to share network resources among competing users. TCP was originally designed primarily for wired networks, and it has performed remarkably well as the Internet scaled up by six orders of magnitude in the past decade. However, many studies have shown that the unmodified standard TCP performs poorly in networks with large bandwidth-delay products and/or lossy wireless links. In this thesis, we analyze the problems TCP exhibits in the wireless communication environment, and develop joint TCP congestion control and wireless-link scheduling schemes for mobile applications. ... Different from the existing solutions, the proposed schemes can be asynchronously implemented without message passing among network nodes; thus they are readily deployable with current infrastructure. Moreover, global convergence/stability of the proposed schemes to optimal equilibrium is established using the Lyapunov method in the network fluid model. Simulation results are provided to evaluate the proposed schemes in practical networks. / by Zhaoquan Li. / Thesis (Ph.D.)--Florida Atlantic University, 2013. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

Siu Chun. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 66-68). / Abstracts in English and Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Thesis Overview --- p.3 / Chapter 2 --- Background and Related work --- p.4 / Chapter 2.1 --- Emergence of IP-over-ATM --- p.4 / Chapter 2.2 --- ATM architecture --- p.5 / Chapter 2.3 --- Scheduling issues in output-queued switch --- p.6 / Chapter 2.4 --- Scheduling issues in input-queued switch --- p.18 / Chapter 3 --- The Deadline-ordered Burst-based Parallel Scheduling Strategy --- p.23 / Chapter 3.1 --- Introduction --- p.23 / Chapter 3.2 --- Switch and queueing model --- p.24 / Chapter 3.2.1 --- Switch model --- p.24 / Chapter 3.2.2 --- Queueing model --- p.25 / Chapter 3.3 --- The DBPS Strategy --- p.26 / Chapter 3.3.1 --- Motivation --- p.26 / Chapter 3.3.2 --- Strategy --- p.31 / Chapter 3.4 --- The Deadline-ordered Burst-based Parallel Iterative Matching --- p.33 / Chapter 3.4.1 --- Algorithm --- p.34 / Chapter 3.4.2 --- An example of DBPIM --- p.35 / Chapter 3.5 --- Simulation results --- p.33 / Chapter 3.6 --- Discussions --- p.46 / Chapter 3.7 --- Future work --- p.47 / Chapter 4 --- The Quasi-static DBPIM Algorithm --- p.50 / Chapter 4.1 --- Introduction --- p.50 / Chapter 4.2 --- Quasi-static path scheduling principle --- p.51 / Chapter 4.3 --- Quasi-static DBPIM algorithm --- p.56 / Chapter 4.4 --- An example of Quasi-static DBPIM --- p.59 / Chapter 5 --- Conclusion --- p.63 / Bibliography --- p.65

The number of Web traffic flows dominates Internet traffic today and most Web interactions are short-lived HTTP connections handled by TCP. Most core Internet routers use Drop Tail queuing which produces bursts of packet drops that contribute to unfair service. This thesis introduces two new active queue management (AQM) algorithms, PISA (PI with Short-lived flows Adjustment) and PIMC (PI with Minimum Cwnd). These AQMs are built on top of the PI (Proportional Integrator). To evaluate the performance of PISA and PIMC, a new simple model of HTTP traffic was developed for the NS-2 simulation. TCP sources inform PISA and PIMC routers of their congestion window by embedding a source hint in the packet header. Using the congestion window, PISA drops packets from short-lived Web flows less than packets from long-lived flows. Using a congestion window, PIMC does not drop a packet when congestion window is below a fixed threshold. This study provides a series of NS-2 experiments to investigate the behavior of PISA and PIMC. The results show fewer drops for both PISA and PIMC that avoids timeouts and increases the rate at which Web objects are sent. PISA and PIMC improve the performance of HTTP flows significantly over PI. PISA performs slightly better than PIMC.

This research is motivated by the recent developments in the Internet Engineering Task Force (IETF) to support seamless integration of moving networks deployed in vehicles to the global Internet. The effort, known as Network Mobility (NEMO), paves the way to support high-speed Internet access in mass transit systems, e.g. trains; buses; ferries; and planes; through the use of on-board mobile routers embedded in the vehicle. One of the critical research challenges of this vision is to achieve high-speed and reliable back-haul connectivity between the mobile router and the rest of the Internet. The problem is particularly challenging due to the fact that a mobile router must rely on wireless links with limited bandwidth and unpredictable quality variations as the vehicle moves around. In this thesis, the multi-homing concept is applied to approach the problem. With multi-homing, mobile router has more than one connection to the Internet. This is achieved by connecting the mobile router to a diverse array of wireless access technologies (e.g., GPRS, CDMA, 802.11, and 802.16) and/or a multiplicity of wireless service providers. While the aggregation helps addressing the bandwidth problem, quality variation problem can be mitigated by employing advanced traffic engineering techniques that dynamically control inbound and outbound traffic over multiple connections. More specifically, the thesis investigates traffic engineering solutions for mobile networks that can effectively address the performance objectives, e.g. maximizing profit for mobile network operator; guaranteeing quality of service for the users; and maintaining fair access to the back-haul bandwidth. Traffic engineering solutions with three different levels of control have been investigated. First, it is shown, using detailed computer simulation of popular applications and networking protocols(e.g., File Transfer Protocol and Transmission Control Protocol), that packet-level traffic engineering which makes decisions of which Internet connection to use for each and every packet, leads to poor system throughput. The main problem with packet-based traffic engineering stems from the fact that in mobile environment where link bandwidths and delay can vary significantly, packets using different connections may experience different delays causing unexpected arrivals at destinations. Second, a maximum utility flow-level traffic engineering has been proposed that aims to maximize a utility function that accounts for bandwidth utilization on the one hand, and fairness on the other. The proposed solution is compared against previously proposed flow-level traffic engineering schemes and shown to have better performance in terms of throughput and fairness. The third traffic engineering proposal addresses the issue of maximizing operator?s profit when different Internet connections have different charging rates, and guaranteeing per user bandwidth through admission control. Finally, a new signaling protocol is designed to allow the mobile router to control its inbound traffic.

There is a growing range of IP-based data and voice applications using mobile devices (e.g. 3rd , 4th generation mobile phones and PDAs) and new access technologies (e.g. Bluetooth, 802.11, GPRS, ADSL). This growth is driving a desire to support mobility at the IP level � in other words, allowing an IP host to keep on communicating with other hosts while roaming between different IP subnetworks. Mobile IPv6 allows hosts to move their physical and topological attachment points around an IPv6 network while retaining connectivity through a single, well-known Home Address. Although Mobile IPv6 has been the subject of simulation studies, the real-world dynamic behavior of Mobile IPv6 is only gradually being experimentally characterised and analysed. This thesis reviews the use of Mobile IPv6 to support mobility between independent 802.11b-attached IPv6 subnets, and experimentally measures and critically evaluates how long an end to end IP path is disrupted when a Mobile IPv6 node shifts from one subnetwork to another (handoff time). The thesis describes the development of an experimental testbed suitable for gathering real-world Mobile IPv6 handoff data using publicly available, standards compliant implementations of Mobile IPv6. (An open-source Mobile IPv6 stack (the KAME release under FreeBSD) was deployed). The component of handoff time due to 802.11b link layer handoff is measured separately to assess its impact on the overall Mobile IPv6 handoff time. Using Mobile IPv6 handoff results, the likely performance impact of Mobile IPv6 handoff on a common webcam application and a bulk TCP data transfer is also evaluated. The impact of handoff on these applications clearly shows that a default Mobile IPv6 environment would be highly disruptive to real-time and interactive applications during handoff events, even if the underlying link-layer handoff was instantaneous.