by Chan Ho Chow. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 65-67). / Abstracts in English and Chinese. / Chapter Chapter 1 --- Introduction --- p.1 / Chapter Chapter 2 --- Background --- p.5 / Chapter 2.1. --- Packet Loss in the Internet --- p.5 / Chapter 2.2. --- Shared Internet --- p.7 / Chapter 2.3. --- Video Streaming --- p.10 / Chapter 2.4. --- Real-time video transmission criteria --- p.11 / Chapter 2.5. --- Existing Video Streaming Protocol --- p.13 / Chapter Chapter 3 --- Transmission Control Protocol (TCP) --- p.16 / Chapter Chapter 4 --- Variable-rate Streaming TCP (VarS-TCP) --- p.22 / Chapter 4.1. --- General Idea --- p.22 / Chapter 4.2. --- Assumptions --- p.25 / Chapter 4.3. --- VarS-TCP Algorithm --- p.26 / Chapter 4.3.1. --- Connection Initialization --- p.26 / Chapter 4.3.2. --- Normal Data Transfer --- p.27 / Chapter 4.4. --- Skipping packets in TCP --- p.32 / Chapter 4.4.1. --- Types of skipped packet --- p.32 / Chapter 4.4.2. --- Acknowledging skipped packets --- p.34 / Chapter 4.4.3. --- Maintaining Normal Data Flow --- p.35 / Chapter 4.4.4. --- Congestion Control --- p.37 / Chapter 4.4.5. --- Packets skipped by receiver --- p.41 / Chapter 4.5. --- Rebuffering --- p.44 / Chapter Chapter 5 --- Simulation Result --- p.45 / Chapter 5.1. --- Accumulating Data --- p.46 / Chapter 5.2. --- Delay Constraints --- p.48 / Chapter 5.3. --- Adapting network situation --- p.50 / Chapter 5.4. --- Sharing bandwidth with TCP --- p.52 / Chapter 5.5. --- Random Traffic --- p.58 / Chapter 5.6. --- Effect of packet skip threshold --- p.59 / Chapter 5.7. --- Effect of round-trip-time --- p.61 / Chapter Chapter 6 --- Conclusion and Future Works --- p.63 / Bibliography --- p.65

El objetivo de la presente tesis es demostrar las ventajas y beneficios de la implementación de la Red Next Generation Network (NGN) en Lima-Metropolitana. La Red NGN está basada en una serie de plataformas y protocolos, los cuales deben trabajar de una manera ordenada y jerárquica para el buen funcionamiento de la red y seguir ofreciendo los servicios actuales así como nuevos servicios de redes avanzadas, todas ellas basadas en plataformas de red IP. Se realizó un estudio mercado de los servicios ofrecidos actualmente por los operadores, en donde se puede apreciar la cantidad de clientes por servicio y la penetración de estos servicios a lo largo de los años 2007-2011. Seguidamente se presentan además los servicios que se podrían ofrecer con el desarrollo de esta tecnología, estos servicios tales como IPTV y teleconferencias, que son ofrecidos en otros países, como México y España, por ejemplo. La Ingeniería del proyecto propone la ubicación de puntos de presencia (PoP) en áreas estratégicas, de tal manera que se atienda las necesidades de los usuarios. Se propone además el tipo de topología a usar así como los elementos de red necesarios para su puesta en servicio. Finalmente se realiza el análisis financiero de los servicios ofrecidos en el sector de telecomunicaciones del mercado de Lima – Metropolitana, basando el estudio en valores obtenidos de los indicadores estadísticos del Regulador Osiptel, permitiendo demostrar la rentabilidad de la implementación de la red propuesta en la presente tesis. / Tesis

El presente proyecto tiene por título: Diseño e Implementación de un Equipo Electrónico para la Tarifación de Llamadas Telefónicas en Locutorios de Voz IP, donde un locutorio se entiende como un conjunto de líneas telefónicas, Voz IP hace referencia a la tecnología que transmite la voz sobre una red IP y la tarifación es el proceso por el cual asignamos un valor monetario (costo) a una llamada telefónica. / Tesis

Sun Haibin. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 89-96). / Abstracts in English and Chinese. / Abstract --- p.i / Chinese Abstract --- p.iii / Acknowledgement --- p.iv / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Background Study and Related Work --- p.5 / Chapter 2.1 --- Victim Exhaustion DoS/DDoS Attacks --- p.6 / Chapter 2.1.1 --- Direct DoS/DDoS Attacks --- p.7 / Chapter 2.1.2 --- Reflector DoS/DDoS Attacks --- p.8 / Chapter 2.1.3 --- Spoofed Packet Filtering --- p.9 / Chapter 2.1.4 --- IP Traceback --- p.13 / Chapter 2.1.5 --- Location Hiding --- p.20 / Chapter 2.2 --- QoS Based DoS Attacks --- p.22 / Chapter 2.2.1 --- Introduction to the QoS Based DoS Attacks --- p.22 / Chapter 2.2.2 --- Countermeasures to the QoS Based DoS Attacks --- p.22 / Chapter 2.3 --- Worm based DoS Attacks --- p.24 / Chapter 2.3.1 --- Introduction to the Worm based DoS Attacks --- p.24 / Chapter 2.3.2 --- Countermeasures to the Worm Based DoS Attacks --- p.24 / Chapter 2.4 --- Low-rate TCP Attack and RoQ Attacks --- p.26 / Chapter 2.4.1 --- General Introduction of Low-rate Attack --- p.26 / Chapter 2.4.2 --- Introduction of RoQ Attack --- p.27 / Chapter 3 --- Formal Description of Low-rate TCP Attacks --- p.28 / Chapter 3.1 --- Mathematical Model of Low-rate TCP Attacks --- p.28 / Chapter 3 2 --- Other forms of Low-rate TCP Attacks --- p.31 / Chapter 4 --- Distributed Detection Mechanism --- p.34 / Chapter 4.1 --- General Consideration of Distributed Detection . --- p.34 / Chapter 4.2 --- Design of Low-rate Attack Detection Algorithm . --- p.36 / Chapter 4.3 --- Statistical Sampling of Incoming Traffic --- p.37 / Chapter 4.4 --- Noise Filtering --- p.38 / Chapter 4.5 --- Feature Extraction --- p.39 / Chapter 4.6 --- Pattern Matching via the Dynamic Time Warping (DTW) Method --- p.41 / Chapter 4.7 --- Robustness and Accuracy of DTW --- p.45 / Chapter 4.7.1 --- DTW values for low-rate attack: --- p.46 / Chapter 4.7.2 --- DTW values for legitimate traffic (Gaussian): --- p.47 / Chapter 4.7.3 --- DTW values for legitimate traffic (Self-similar): --- p.48 / Chapter 5 --- Low-Rate Attack Defense Mechanism --- p.52 / Chapter 5.1 --- Design of Defense Mechanism --- p.52 / Chapter 5.2 --- Analysis of Deficit Round Robin Algorithm --- p.54 / Chapter 6 --- Fluid Model of TCP Flows --- p.56 / Chapter 6.1 --- Fluid Math. Model of TCP under DRR --- p.56 / Chapter 6.1.1 --- Model of TCP on a Droptail Router --- p.56 / Chapter 6.1.2 --- Model of TCP on a DRR Router --- p.60 / Chapter 6.2 --- Simulation of TCP Fluid Model --- p.62 / Chapter 6.2.1 --- Simulation of Attack with Single TCP Flow --- p.62 / Chapter 6.2.2 --- Simulation of Attack with Multiple TCP flows --- p.64 / Chapter 7 --- Experiments --- p.69 / Chapter 7.1 --- Experiment 1 (Single TCP flow vs. single source attack) --- p.69 / Chapter 7.2 --- Experiment 2 (Multiple TCP flows vs. single source attack) --- p.72 / Chapter 7.3 --- Experiment 3 (Multiple TCP flows vs. synchro- nized distributed low-rate attack) --- p.74 / Chapter 7.4 --- Experiment 4 (Network model of low-rate attack vs. Multiple TCP flows) --- p.77 / Chapter 8 --- Conclusion --- p.83 / Chapter A --- Lemmas and Theorem Derivation --- p.85 / Bibliography --- p.89

Ma Ke. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 64-68). / Abstracts in English and Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Background --- p.1 / Chapter 1.2 --- Motivation --- p.2 / Chapter 1.3 --- Contribution --- p.3 / Chapter 1.4 --- Organization --- p.4 / Chapter 2 --- Literature Review --- p.5 / Chapter 2.1 --- Overview --- p.5 / Chapter 2.2 --- Multi-Path Routing --- p.6 / Chapter 2.2.1 --- OSPF-ECMP --- p.7 / Chapter 2.2.2 --- LFI --- p.7 / Chapter 2.2.3 --- QSMP and QDMP --- p.9 / Chapter 2.2.4 --- WDP --- p.10 / Chapter 2.2.5 --- DMPR --- p.11 / Chapter 2.2.6 --- Cidon's Analysis --- p.13 / Chapter 3 --- LSLF and SLSLF Conditions --- p.15 / Chapter 3.1 --- Problem Formulation --- p.15 / Chapter 3.2 --- LFI Conditions --- p.16 / Chapter 3.3 --- LSLF Conditions --- p.17 / Chapter 3.4 --- SLSLF Conditions --- p.20 / Chapter 4 --- Performance of LSLF and SLSLF --- p.24 / Chapter 4.1 --- Overview --- p.24 / Chapter 4.2 --- Numerical Results --- p.26 / Chapter 5 --- Analysis of Multi-path Routing --- p.42 / Chapter 5.1 --- Assumptions --- p.43 / Chapter 5.2 --- M/M/C/C Queueing System --- p.44 / Chapter 5.3 --- Performance Analysis --- p.48 / Chapter 5.3.1 --- "Case 1 Only QoS flows between (s, d) exist" --- p.48 / Chapter 5.3.2 --- Case 2 QoS flows between other SD pairs also exist --- p.50 / Chapter 5.3.3 --- Case 3 A QoS flow can try m times before it is dropped --- p.53 / Chapter 5.4 --- Numerical Results --- p.56 / Chapter 6 --- Conclusion --- p.62

In order to serve hundreds of millions of users, contemporary content providers employ tens of thousands of servers to scale their systems. The system software in these environments, however, is struggling to keep up with the increase in demand: contemporary network and storage stacks, as well as related APIs (e.g., BSD socket API) follow a `one-size-fits-all' design, heavily emphasising generality and feature richness at the cost of performance, leaving crucial hardware resources unexploited. Despite considerable prior research in improving I/O performance for conventional stacks, substantial hardware potential still remains unexploited because most of these proposals are fundamentally limited in their scope and effectiveness, as they still have to fit in a general-purpose design. In this dissertation, I argue that specialisation and microarchitectural awareness are necessary in system software design to effectively exploit hardware capabilities, and scale I/O performance. In particular, I argue that trading off generality and compatibility, allows us to radically re-architect the stack emphasising application-specific optimisations and efficient data movement throughout the hardware to improve performance. I first demonstrate that conventional general-purpose stacks fail to effectively utilise contemporary hardware while serving critical Internet workloads, and show why modern microarchitectural properties play a critical role in scaling I/O performance. I then identify core decisions in Operating Systems design that, although they were originally introduced to optimise performance, are now proven redundant or even detrimental. I propose clean-slate, specialised architectures for network and storage stacks designed to exploit modern hardware properties, and application domain-specific knowledge in order to sidestep historical bottlenecks in systems I/O performance, and achieve great scalability. With thorough evaluation of my systems, I illustrate how specialisation and greater microarchitectural awareness could lead to dramatic performance improvements, which could ultimately translate to improved scalability and reduced capital expenditure simultaneously.

Tese de mestrado integrado. Engenharia Electrotécnica e de Computadores (Major Automação). Faculdade de Engenharia. Universidade do Porto. 2009

The main aim of the project is to launch multiple processes and have those processes communicate with each other using peer to peer communication to eliminate the problems of multiple processes running on a single server, and multiple processes running on inhomogeneous servers as well as the problems of scalability. This entire process is done using MPICH which is a high performance and portable implementation of Message Passing Interface standard. The project involves setting up the passwordless authentication between two local servers with the help of SSH connection. By establishing a peer to peer communication and by using a unique shell script which is written using MPICH and its derivatives, I am going to demonstrate the process of inter-process communication between the servers.

Voice over IP and video applications continue to increase the amount of traffic over the Internet. These applications utilize the UDP protocol because TCP is not suitable for streaming applications. The flow and congestion control mechanisms of TCP can change the connection transmission rate too drastically, affecting the user-perceived quality of the transmission. Also, the TCP protocol provides a level of reliability that may waste network resources, retransmitting packets that have no value. On the other hand, the use of end-to-end flow and congestion control mechanisms for streaming applications has been acknowledged as an important measure to ease or eliminate the unfairness problem that exist when TCP and UDP share the same congested bottleneck link. Actually, router-based and end-to-end solutions have been proposed to solve this problem. This thesis introduces a new end-to-end protocol based on TCP SACK called SF-SACK that promises to be smooth enough for streaming applications while implementing the known flow and congestion control mechanisms available in TCP. Through simulations, it is shown that in terms of smoothness the SF-SACK protocol is considerably better than TCP SACK and only slightly worse than TFRC. Regarding friendliness, SF-SACK is not completely fair to TCP but considerably fairer than UDP. Furthermore, if SF-SACK is used by both streaming and data-oriented applications, complete fairness is achieved. In addition, SF-SACK only needs sender side modifcations and it is simpler than TFRC.

In recent times, the imminent lack of public IPv4 addresses has attracted the attention of both the research community and industry. The cellular industry has decided to combat this problem by using IPv6 for all new terminals. However, the success of 3G network deployment will depend on the services offered to end users. Currently, almost all services reside in the IPv4 address space, making them inaccessible to users in IPv6 networks. Thus, an intermediate translation mechanism is required. Previous studies on network address translation methods have shown that Realm Base Kluge Address Heuristic-IP, REBEKAH-IP supports all types of services that can be offered to IPv6 hosts from the public IPv4 based Internet, and provides excellent scalability. However, the method suffers from an ambiguity problem which may lead to call blocking. This thesis presents an improvement to REBEKAH-IP scheme in which the side effect is removed, creating a robust and fully scalable system. The improvement can be divided into two major tasks including a full investigation on the scalability of addressing and improvements to the REBEKAH-IP scheme that allow it to support important features such as ICMP and IP mobility. To address the first task a method called REBEKAH-IP with Port Extension (RPX) is introduced. RPX is extended from the original REBEKAH-IP scheme to incorporate centralised management of both IP address and port numbers. This method overcomes the ambiguity problem, and improves scalability. We propose a priority queue algorithm to further increase scalability. Finally, we present extensive simulation results on the practical scalability of RPX with different traffic compositions, to provide a guideline of the expected scalability in large-scale networks. The second task concerns enabling IP based communication. Firstly, we propose an ICMP translation mechanism which allows the RPX server to support important end-toend control functions. Secondly, we extend the RPX scheme with a mobility support scheme based on Mobile IP. In addition, we have augmented Mobile IP with a new tunneling mechanism called IP-in-FQDN tunneling. The mechanism allows for unique mapping despite the sharing of IP addresses while maintaining the scalability of RPX. We examine the viability of our design through our experimental implementation.