by Ma Chun Ho Eric. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 102-105). / Abstracts in English and Chinese. / INTERNET ROUTING AND PRICING --- p.1 / ABSTRACT --- p.I / ACKNOWLEDGEMENTS --- p.III / LIST OF FIGURES --- p.IV / LIST OF TABLES --- p.VI / CONTENTS --- p.VII / Chapter CHAPTER1 --- Introduction --- p.1 / Chapter 1.1 --- What is Internet? --- p.1 / Chapter 1.2 --- Internet Routing and Pricing --- p.3 / Chapter 1.3 --- Overview of QoS Routing --- p.4 / Chapter 1.3.1 --- Classification of Routing --- p.6 / Chapter 1.3.2 --- Optimal Routing --- p.7 / Chapter 1.4 --- An Introduction to Internet Economics --- p.8 / Chapter 1.4.1 --- Internet Externality --- p.9 / Chapter 1.4.2 --- Current Pricing Practice --- p.10 / Chapter 1.4.3 --- Network Interconnection --- p.14 / Chapter 1.4 --- Organization of Thesis --- p.16 / Chapter CHAPTER2 --- Economic Theory for Interconnection Model --- p.18 / Chapter 2.1 --- Introduction --- p.18 / Chapter 2.2 --- Demand and Supply --- p.20 / Chapter 2.2.1 --- Consumer Behavior --- p.20 / Chapter 2.2.2 --- Demand Curve --- p.25 / Chapter 2.2.3 --- Price Elasticity --- p.30 / Chapter 2.2.4 --- Estimation of Market Demand --- p.32 / Chapter 2.3 --- Market Structure --- p.33 / Chapter 2.3.1 --- Competitive Firm --- p.34 / Chapter 2.3.2 --- Monopoly --- p.35 / Chapter 2.3.3 --- Oligopoly --- p.35 / Chapter 2.4 --- Game Theory --- p.35 / Chapter 2.4.1 --- The Payoff Matrix of a game --- p.36 / Chapter 2.4.2 --- Nash Equilibrium --- p.37 / Chapter 2.4.3 --- Mixed Strategies --- p.38 / Chapter 2.4.4 --- Existence of Nash Equilibrium --- p.39 / Chapter 2.5 --- Summary --- p.39 / Chapter CHAPTER3 --- Problem Formulation Interconnection Network for Pricing and Routing in Internet --- p.40 / Chapter 3.1 --- Introduction --- p.40 / Chapter 3.2 --- Problem Formulation --- p.41 / Chapter 3.2 --- Existence of NEP Interconnection Network --- p.46 / Chapter 3.3 --- "A ""Cookbook"" Procedure" --- p.53 / Chapter 3.4 --- Cookbook Examples --- p.54 / Chapter 3.5 --- Summary --- p.65 / Chapter CHAPTER4 --- Price Competition for Interconnection Models --- p.66 / Chapter 4.1 --- Introduction --- p.66 / Chapter 4.2 --- Competitive Pricing of Parallel Networks --- p.66 / Chapter 4.2.1 --- Model and Problem Formulation --- p.67 / Chapter 4.2.2 --- Existence of Nash Equilibrium Point --- p.68 / Chapter 4.2.3 --- Numerical Example and Properties --- p.71 / Chapter 4.3 --- Price Collusion for Serial Networks --- p.75 / Chapter 4.3.1 --- Model and Problem Formulation --- p.75 / Chapter 4.3.2 --- Existence of Nash Equilibrium Point --- p.77 / Chapter 4.3.3 --- Numerical Example and Properties --- p.79 / Chapter 4.4 --- Summary --- p.83 / Chapter CHAPTER5 --- Price Distortion for Series-Parallel Networks with Dominant Carriers --- p.85 / Chapter 5.1 --- Problem Motivation and Formulation --- p.85 / Chapter 5.2 --- Properties under NEP --- p.90 / Chapter 5.3 --- A Simple Simulation --- p.95 / Chapter 5.5 --- Summary --- p.98 / Chapter CHAPTER6 --- Conclusion --- p.99 / BIBLIOGRAPHY --- p.102

by Hui Chi Chun Ronald. / Thesis submitted in: December 1998. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 62-66). / Abstract also in Chinese. / Chapter Chapter 1. --- Introduction --- p.1 / Chapter Chapter 2. --- AON Architecture --- p.7 / Chapter 2.1 --- WCC Dimension Reduction Node Architecture --- p.10 / Chapter 2.2 --- Restoration of a Survivable AON --- p.13 / Chapter Chapter 3. --- Network Dimensioning Problem --- p.15 / Chapter 3.1 --- Problem Setting --- p.16 / Chapter 3.2 --- Two Solution Approaches --- p.16 / Chapter 3.2.1 --- Minimum Variance Algorithm (MVA) --- p.17 / Chapter 3.2.2 --- Minimum Variance Subroutine (MVS) --- p.19 / Chapter 3.3 --- Shortest Path Algorithm (SPA) --- p.21 / Chapter 3.4 --- An Illustrative Example --- p.22 / Chapter 3.5 --- Performance Comparisons --- p.26 / Chapter Chapter 4. --- Network Management for AON Restoration --- p.31 / Chapter 4.1 --- Surveillance Network --- p.31 / Chapter 4.2 --- Signaling Network --- p.32 / Chapter 4.3 --- Network Management System --- p.32 / Chapter 4.4 --- CCS7 Adaptation for Supporting AON Restoration --- p.34 / Chapter Chapter 5. --- Complete Restoration Algorithm for AON --- p.40 / Chapter 5.1 --- Link-Based Restoration Algorithm --- p.43 / Chapter 5.2 --- Source-Based Restoration Algorithm --- p.44 / Chapter 5.3 --- Case Studies --- p.45 / Chapter 5.3.1 --- Case I and II --- p.45 / Chapter 5.3.2 --- Case III --- p.50 / Chapter 5.4 --- Completely Restorable Network planning --- p.52 / Chapter 5.5 --- A Summary on Problem Formulations --- p.55 / Chapter Chapter 6. --- Conclusion --- p.57 / Reference --- p.62

Lau Kwok Hung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 66-67). / Abstracts in English and Chinese. / Acknowledgement --- p.1 / Abstract --- p.2 / 摘要 --- p.3 / Chapter Chapter 1 --- Introduction --- p.6 / Chapter Chapter 2 --- Background and Related Work --- p.9 / Chapter 2.1 --- Application-Layer Bandwidth Differentiation --- p.9 / Chapter 2.2 --- Related Work --- p.14 / Chapter 2.2.1 --- Bandwidth Differentation --- p.14 / Chapter 2.2.2 --- Shared Congestion Management --- p.15 / Chapter 2.2.3 --- Flow Partition --- p.16 / Chapter Chapter 3 --- VPS Protocol Architecture --- p.17 / Chapter 3.1 --- Virtual and Actual Flows --- p.18 / Chapter 3.2 --- VPS Controller --- p.21 / Chapter Chapter 4 --- ACK Translation --- p.25 / Chapter 4.1 --- Fast Retransmit and Fast Recovery --- p.27 / Chapter 4.2 --- Timeout --- p.30 / Chapter 4.3 --- Packet and ACK Reordering --- p.33 / Chapter 4.4 --- False Duplicate ACK Suppression --- p.35 / Chapter 4.5 --- Maxburst --- p.37 / Chapter 4.6 --- Memory Overhead and Computation Complexity --- p.38 / Chapter Chapter 5 --- Bandwidth Differentiation --- p.41 / Chapter 5.1 --- Distribution of Virtual Packets --- p.41 / Chapter 5.2 --- Temporary Suspension of Actual Flows --- p.43 / Chapter 5.3 --- Receive Window Limit --- p.44 / Chapter 5.4 --- Limited Data Transmission --- p.44 / Chapter Chapter 6 --- Performance Evaluatoin --- p.45 / Chapter 6.1 --- Performance Metric --- p.45 / Chapter 6.2 --- Simulation Setup --- p.46 / Chapter 6.3 --- Performance over Different Time Scales --- p.47 / Chapter 6.4 --- Performance over Different Bottleneck Bandwidth --- p.53 / Chapter 6.5 --- Performance over Different Application-specified Ratios --- p.54 / Chapter 6.6 --- Performance over Different Number of Flows --- p.57 / Chapter 6.7 --- Heterogeneous Receivers --- p.60 / Chapter Chapter 7 --- Conclusions and Future Work --- p.65 / Bibliography --- p.66

Zheng, Pengxuan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 53-57). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgments --- p.v / Table of Contents --- p.vi / List of Figures --- p.viii / List of Tables --- p.ix / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Motivation --- p.1 / Chapter 1.2 --- Related Work --- p.2 / Chapter 1.3 --- Our Contribution --- p.3 / Chapter 1.4 --- Organization of the Thesis --- p.4 / Chapter Chapter 2 --- Background Overview --- p.6 / Chapter 2.1.1 --- Traditional Wireless Networks --- p.6 / Chapter 2.2 --- Exponential Backoff --- p.7 / Chapter 2.2.1 --- Introduction --- p.7 / Chapter 2.2.2 --- Algorithm --- p.8 / Chapter 2.2.3 --- Assumptions --- p.9 / Chapter 2.3 --- System Description --- p.9 / Chapter 2.3.1 --- MPR Capability --- p.9 / Chapter 2.3.2 --- Backoff Slot --- p.10 / Chapter 2.3.3 --- Carrier-sensing and Non-carrier-sensing Systems --- p.11 / Chapter Chapter 3 --- Multipacket Reception in WLAN --- p.12 / Chapter 3.1 --- MAC Protocol Description --- p.13 / Chapter 3.2 --- Physical Layer Methodology --- p.16 / Chapter 3.2.1 --- Blind RTS Separation --- p.17 / Chapter 3.2.2 --- Data Packet Detection --- p.19 / Chapter Chapter 4 --- Exponential Backoff with MPR --- p.21 / Chapter 4.1 --- Analytical Model --- p.22 / Chapter 4.1.1 --- Markov Model --- p.22 / Chapter 4.1.2 --- Relations betweenpt andpc --- p.23 / Chapter 4.2 --- Simulation Settings --- p.26 / Chapter 4.3 --- Asymptotic Behavior of Exponential Backoff --- p.27 / Chapter 4.3.1 --- Convergence ofpt andpc --- p.27 / Chapter 4.3.2 --- Convergence of Npt --- p.29 / Chapter Chapter 5 --- Non-carrier-sensing System --- p.31 / Chapter 5.1 --- Performance Analysis --- p.31 / Chapter 5.1.1 --- Throughput Derivation --- p.31 / Chapter 5.1.2 --- Throughput Analysis --- p.32 / Chapter 5.1.3 --- Convergence of S --- p.36 / Chapter 5.2 --- Infinite Population Model --- p.38 / Chapter 5.2.1 --- Attempt Rate --- p.38 / Chapter 5.2.2 --- Asymptotic Throughput of Non-carrier-sensing System --- p.39 / Chapter Chapter 6 --- Carrier-sensing System --- p.43 / Chapter 6.1 --- Throughput Derivation --- p.43 / Chapter 6.2 --- Asymptotic Behavior --- p.44 / Chapter Chapter 7 --- General MPR Model --- p.48 / Chapter Chapter 8 --- Conclusions --- p.51 / Bibliography --- p.53

Network applications and Internet services fail all too frequently. However, end users cannot effectively identify the root cause using traditional troubleshooting techniques due to the limited capability to distinguish failures caused by local network elements from failures caused by elements located outside the local area network. To overcome these limitations, we propose a new approach, one that leverages collaboration of user machines to assist end users in diagnosing various failures related to Internet connectivity and poor network performance. First, we present DYSWIS ("Do You See What I See?"), an automatic network fault detection and diagnosis system for end users. DYSWIS identifies the root cause(s) of network faults using diagnostic rules that consider diverse information from multiple nodes. In addition, the DYSWIS rule system is specially designed to support crowdsourced and distributed probes. We also describe the architecture of DYSWIS and compare its performance with other tools. Finally, we demonstrate that the system successfully detects and diagnoses network failures which are difficult to diagnose using a single-user probe. Failures in lower layers of the protocol stack also have the potential to disrupt Internet access; for example, slow Internet connectivity is often caused by poor Wi-Fi performance. Channel contention and non-Wi-Fi interference are the primary reasons for this performance degradation. We investigate the characteristics of non-Wi-Fi interference that can severely degrade Wi-Fi performance and present WiSlow ("Why is my Wi-Fi slow?"), a software tool that diagnoses the root causes of poor Wi-Fi performance. WiSlow employs user-level network probes and leverages peer collaboration to identify the physical location of these causes. The software includes two principal methods: packet loss analysis and 802.11 ACK number analysis. When the issue is located near Wi-Fi devices, the accuracy of WiSlow exceeds 90%. Finally, we expand our collaborative approach to the Internet of Things (IoT) and propose a platform for network-troubleshooting on home devices. This platform takes advantage of built-in technology common to modern devices --- multiple communication interfaces. For example, when a home device has a problem with an interface it sends a probe request to other devices using an alternative interface. The system then exploits cooperation of both internal devices and remote machines. We show that this approach is useful in home networks by demonstrating an application that contains actual diagnostic algorithms.

No description available.

Jiang Libin. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 84-87). / Abstracts in English and Chinese. / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Motivations and Contributions --- p.1 / Chapter 1.2 --- Related Works --- p.3 / Chapter 1.3 --- Organization of the Thesis --- p.4 / Chapter Chapter 2 --- Background --- p.6 / Chapter 2.1 --- IEEE 802.11 --- p.6 / Chapter 2.1.1 --- Basics of 802.11 Standard --- p.6 / Chapter 2.1.2 --- Types of Networks --- p.10 / Chapter 2.1.3 --- Automatic Repeat request (ARQ) in 802.11b --- p.11 / Chapter 2.2 --- Hidden- and Exposed-node Problems --- p.15 / Chapter Chapter 3 --- Physical Interference Constraints and Protocol Constraints --- p.19 / Chapter 3.1 --- Protocol-independent Physical Interference Constraints --- p.19 / Chapter 3.2 --- Protocol-specific Physical Interference Constraints --- p.21 / Chapter 3.3 --- Protocol Collision-Prevention Constraints in 802.11 --- p.22 / Chapter 3.3.1 --- Transmitter-Side Carrier-Sensing Constraints --- p.22 / Chapter 3.3.2 --- Receiver-Side Carrier Sensing Constraints --- p.24 / Chapter Chapter 4 --- Formal Definitions of EN and HN Using a Graph Model --- p.27 / Chapter Chapter 5 --- Selective Disregard of NAVs (SDN) --- p.36 / Chapter 5.1 --- SDN. I - Turning off Physical Carrier Sensing and Using Receiver Restart Mode --- p.38 / Chapter 5.2 --- SDN.II - Selective Disregard of NAV (SDN) --- p.38 / Chapter 5.3 --- SDN.III - Constructing s-graph using Power Exchange Algorithm (PE) --- p.40 / Chapter Chapter 6 --- EN and Its Impact on Scalability --- p.42 / Chapter 6.1 --- Validation of SDN by NS-2 Simulations --- p.43 / Chapter 6.2 --- Scalability of SDN --- p.46 / Chapter 6.3 --- Non-Scalability of 802.11 --- p.47 / Chapter Chapter 7 --- Hidden-node Free Design (HFD) --- p.51 / Chapter 7.1 --- HFD for IEEE 802.11 Basic Access Mode --- p.52 / Chapter 7.1.1 --- HFD for basic access mode --- p.52 / Chapter 7.1.2 --- Proof of the HN-free property --- p.56 / Chapter 7.2 --- HFD for IEEE 802.11 RTS/CTS Access Mode --- p.59 / Chapter Chapter 8 --- Performance Evaluation of HFD --- p.62 / Chapter 8.1 --- HFD for Basic Access Mode --- p.62 / Chapter 8.2 --- HFD for RTS/CTS Access Mode --- p.64 / Chapter Chapter 9 --- Combination of SDN and HFD --- p.68 / Chapter Chapter 10 --- Conclusion --- p.75 / Appendices --- p.78 / References --- p.84

OFS provisions bandwidth in the granularity of one wavelength. With such a coarse granularity, most applications including video download, HDTV, 3D movie, and 3D TV etc. will have very short flow sizes, in the order of seconds or even sub-second, which brings challenges to the utilization efficiency of bandwidth capacity. In this thesis we study the performance of OFS for short flows. The constraint of network resources is investigated. The effect of destination and path blocking is studied. A distributed scheduling protocol called Multi-Destination Control Protocol (MDCP) is proposed to deal with such constraint. Both single wavelength and multi-wavelength configurations are studied and characterized. Simulation results demonstrate that MDCPcan improve the OFS network throughput significantly and can be as much as eighty to one hundred percent for a single-wavelength OFS network. Even for an OFS network with four wavelengths, the throughput improvement can still approach 40%. / The Internet traffic has been growing tremendously. China Telecom predicts that the compound annual growth rate of IP traffic for the next decade is at 56% - 80% and the backbone capacity will grow by another two orders of magnitudes. Furthermore, the power consumption incurred by the next generation of huge electronic IP packet switching routers in the backbone will exceed gigawatts. In view of the grave enviromnental concerns, there is a great need for a more efficient way of transporting and switching the bits. This thesis investigates a new all-optical networking technology called optical flow switching (OFS). OFS bypasses electronic routers, and provides end-to-end transparent connections, thus taking full advantage of the enormous transmission capacity of optical networks and enjoying the extremely low error rate of transparent data transmission. The most important point about OFS is that it reduces the electrical power consumption by off-loading the huge electronic routers, which could be a major constraint for future Internet growth. Unlike many other exotic all-optical switching technologies, OFS is immediately deployable using the current optical technologies, Therefore OFS is very attractive for the next generation optical networks. / Qian, Zhengfeng. / Adviser: Kwok-wai Cheung. / Source: Dissertation Abstracts International, Volume: 73-04, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 113-118). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Modern data centres provide large aggregate capacity in the backbone of networks so that servers can theoretically communicate with each other at their maximum rates. However, the Transport Control Protocol (TCP) cannot efficiently use this large capacity even if Equal-Cost Multi-Path (ECMP) routing is enabled to exploit the existence of parallel paths. MultiPath TCP (MPTCP) can effectively use the network resources of such topologies by performing fast distributed load balancing. MPTCP is an appealing technique for data centres that are very dynamic in nature. However, it is ill-suited for handling short flows since it increases their flow completion time. To mitigate these problems, we propose Maximum MultiPath TCP (MMPTCP), a novel transport protocol for modern data centres. Unlike MPTCP, it provides high performance for all network flows. It also decreases the bursty nature of data centres, which is essentially rooted in traffic patterns of short flows. MMPTCP achieves these nice features by randomising a flow's packets via all parallel paths to a destination during the initial phase of data transmission until a certain amount of data is delivered. It then switches to MPTCP with several subflows in which data transmission is governed by MPTCP congestion control. In this way, short flows are delivered very fast via the initial phase only, and long flows are delivered by MPTCP with several subflows. We evaluate MMPTCP in a FatTree topology under various network conditions. We found that MMPTCP decreases the loss rate of all the links throughout the network and helps competing flows to achieve a better performance. Unlike MPTCP with a fixed number of subflows, MMPTCP offers high burst tolerance and low-latency for short flows while it maintains high overall network utilisation. MMPTCP is incrementally deployable in existing data centres because it does not require any modification to the network and application layers.

Publish/Subscribe systems hold strong assumptions of the expected behaviour of clients and routers, as it is assumed they all abide by the matching and routing protocols. Assumptions of implicit trust between the components of the publish/subscribe infrastructure are acceptable where the underlying event distribution service is under the control of a single or multiple co-operating administrative entities and contracts between clients and these authorities exist, however there are application contexts where these presumptions do not hold. In such environments, such as ad hoc networks, there is the possibility of selfish and malicious behaviour that can lead to disruption of the routing and matching algorithms. The most commonly researched approach to security in publish/subscribe systems is role-based access control (RBAC). RBAC is suitable for ensuring confidentiality, but due to the assumption of strong identities associated with well defined roles and the absence of monitoring systems to allow for adaptable policies in response to the changing behaviour of clients, it is not appropriate for environments where: identities can not be assigned to roles in the absence of a trusted administrative entity; long-lived identities of entities do not exist; and where the threat model consists of highly adaptable malicious and selfish entities. Motivated by recent work in the application of trust and reputation to Peer-to-Peer networks, where past behaviour is used to generate trust opinions that inform future transactions, we propose an approach where the publish/subscribe infrastructure is constructed and re-configured with respect to the trust preferences of clients and routers. In this thesis, we show how Publish/Subscribe trees (PSTs) can be constructed with respect to the trust preferences of publishers and subscribers, and the overhead costs of event dissemination. Using social welfare theory, it is shown that individual trust preferences over clients and routers, which are informed by a variety of trust sources, can be aggregated to give a social preference over the set of feasible PSTs. By combining this and the existing work on PST overheads, the Maximum Trust PST with Overhead Budget problem is defined and is shown to be in NP-complete. An exhaustive search algorithm is proposed that is shown to be suitable only for very small problem sizes. To improve scalability, a faster tabu search algorithm is presented, which is shown to scale to larger problem instances and gives good approximations of the optimal solutions. The research contributions of this work are: the use of social welfare theory to provide a mechanism to establish the trustworthiness of PSTs; the finding that individual trust is not interpersonal comparable as is considered to be the case in much of the trust literature; the Maximum Trust PST with Overhead Budget problem; and algorithms to solve this problem.