Spelling suggestions: "subject:"computer networks - eliability"" "subject:"computer networks - deliability""
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Generalized survivable network. / CUHK electronic theses & dissertations collectionJanuary 2006 (has links)
A comprehensive framework has been developed for designing a GSN. The focus of this thesis is the capacity planning problem which finds the edge capacities for a given physical topology with specifications of the I/O constraints at the nodes. Two kinds of GSN are studied: (1) For the design of a Wide-Sense Non-Blocking GSN (WSNB-GSN), a rigorous mathematical framework is presented. Duality transformation technique that transforms the initial, infinite and infeasible mathematical formulation into a finite feasible formulation is shown. A procedure for finding the realizable lower bound of the cost of a WSNB-GSN is presented and two different solution approaches are proposed. (2) For the design of a Rearrangeably Non-Blocking GSN (RNB-GSN), a straightforward mathematical formulation is presented first. A procedure using the cut condition to find the lower bound of the cost of a RNB-GSN with a general topology is shown then. The optimal solution in the design of a RNB-GSN with an unlimited-size ring topology is demonstrated with a theorem. / Dynamic bandwidth provisioning and full survivability against link failures are two of the most important requirements for future optical networks. Since previous methodologies could not deal with these two issues simultaneously, a new survivable network concept called the "Generalized Survivable Network" (GSN) is proposed. Generalized Survivable Network incorporates the non-blocking network concept into the survivable network design. Here, "generalized" means the generalization of a network from satisfying a single demand matrix to satisfying the set of all allowable demand matrices under the Input and Output (I/O) access capacity constraints at the network nodes. / Numerical experiments have been carried out to verify the performance of GSN. It is demonstrated that the deploying cost of a WSNB-GSN is within a factor of 2 compared with that of a random sample of a single-period survivable network. The cost of building a RNB-GSN with a ring topology is shown to be about 14% to 45% less than that of building a WSNB-GSN. The framework for planning a GSN is applicable to network planning for future optical networks and survivable IP networks. / Ho Kwok-shing. / "September 2006." / Adviser: Cheung Kwok Wai. / Source: Dissertation Abstracts International, Volume: 68-03, Section: B, page: 1823. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (p. 118-124). / 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, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.
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Annual report for the projects: Data Network Reliability. / Data network reliability21 June 2002 (has links)
Cover title, 1975/76- : Data network reliability; annual report. Principal investigator, 1975/76- : J.M. Wozencraft. Report year ends June 30. Vols. for 1975/76- report on research supported by Information Processing Technology Office, Defense Advanced Research Projects Agency, U.S. Dept. of Defense, ARPA order no. 3045.5-7-75, program code no. 5T10, ONR/N00014-75-C-1183, ONR contract no. 049-383.
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Fault-tolerant ring embedding in De Bruijn networksRowley, Robert A. 02 December 1993 (has links)
Graduation date: 1994
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Multi-path streaming and dynamic end-point adaptation.January 2002 (has links)
Tung, Tak Fu. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 66-68). / Abstracts in English and Chinese. / Chapter 1 --- Introduction to Multi-path Streaming and Dynamic End-point Adaptation --- p.1 / Chapter 1.1 --- Multi-path Streaming --- p.2 / Chapter 1.2 --- Dynamic End-point Adaptation --- p.4 / Chapter 2 --- Related Work --- p.6 / Chapter 3 --- Path Loss Model --- p.10 / Chapter 3.1 --- Bursty Loss --- p.10 / Chapter 3.2 --- Gilbert Model --- p.11 / Chapter 3.2.1 --- Discrete-time Gilbert Model --- p.11 / Chapter 3.2.2 --- Continuous-time Gilbert Model --- p.12 / Chapter 4 --- Loss Recovery / Chapter 4.1 --- Automatic Repeat Request (ARQ) --- p.17 / Chapter 4.2 --- Forward Error Correction (FEC) --- p.18 / Chapter 5 --- Connection Adaptation --- p.23 / Chapter 5.1 --- Path Quality --- p.23 / Chapter 5.2 --- Effect of Shared Congestion Point --- p.24 / Chapter 5.2.1 --- Point-of-Congestion Detection --- p.25 / Chapter 5.3 --- Load Distribution --- p.27 / Chapter 6 --- Analytical Evaluation --- p.28 / Chapter 6.1 --- Performance Analysis of SP vs. Multi-path Streaming (without FEC) --- p.29 / Chapter 6.2 --- Performance Analysis of SP vs. Multi-path Streaming (with FEC) --- p.36 / Chapter 7 --- Experiments and Simulations --- p.42 / Chapter 7.1 --- Effect of Correlated Bursty Losses on Video Quality --- p.42 / Chapter 7.2 --- Analytical Model Based Evaluation --- p.44 / Chapter 7.2.1 --- Data Loss Rate --- p.44 / Chapter 7.2.2 --- Data Loss Rate as a function of FEC parameters --- p.46 / Chapter 7.2.3 --- Conditional Error Burst Length --- p.48 / Chapter 7.2.4 --- Lag-1 Autocorrelation --- p.49 / Chapter 7.2.5 --- Effects of Load Distribution Among Senders --- p.50 / Chapter 7.2.6 --- Sensitivity Analysis --- p.51 / Chapter 7.2.7 --- Effects of Shared Points of Congestion on Various Perfor- mance Metrics --- p.53 / Chapter 7.3 --- Simulation Model Based Evaluation --- p.55 / Chapter 7.3.1 --- Simulation Setup --- p.55 / Chapter 7.3.2 --- Data Loss Rate --- p.57 / Chapter 7.3.3 --- Data Loss Rate as a function of FEC parameters --- p.58 / Chapter 7.3.4 --- Conditional Error Burst Length --- p.59 / Chapter 7.3.5 --- Lag-1 Autocorrelation --- p.60 / Chapter 7.3.6 --- Effects of Load Distribution among Senders --- p.61 / Chapter 7.3.7 --- Sensitivity Analysis --- p.62 / Chapter 7.3.8 --- Effects of Shared Points of Congestion on Various Perfor- mance Metrics --- p.63 / Chapter 8 --- Conclusion --- p.65
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Performance analysis of delay tolerant networks under resource constraints and node heterogeneity.January 2007 (has links)
Ip, Yin Ki. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 96-102). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgement --- p.iv / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Background Study --- p.6 / Chapter 2.1 --- DTN Reference Implementation Model --- p.7 / Chapter 2.2 --- DTN Applications --- p.9 / Chapter 2.3 --- Multiple-copy Routing Strategies --- p.11 / Chapter 2.4 --- Buffer Management Strategies --- p.12 / Chapter 2.5 --- Performance Modeling of Multiple-copy Routing --- p.14 / Chapter 2.6 --- Conclusion on Background Study --- p.18 / Chapter 3 --- DTN with Resource Constraints --- p.20 / Chapter 3.1 --- Introduction --- p.20 / Chapter 3.2 --- Related Work --- p.21 / Chapter 3.3 --- "System Model, Replication, Forwarding and Buffer Management Strategies" --- p.22 / Chapter 3.4 --- Performance Evaluation --- p.29 / Chapter 3.4.1 --- Analysis on single-message-delivery with unlimited network resource --- p.29 / Chapter 3.4.2 --- Simulation study on multi-message-delivery with limited resource constraint --- p.34 / Chapter 3.5 --- Conclusion on DTN with Resource Constraints --- p.39 / Chapter 4 --- Multiple-copy Routing in DTN with Heteroge- neous Node Types --- p.41 / Chapter 4.1 --- Introduction --- p.41 / Chapter 4.2 --- Related Work --- p.44 / Chapter 4.3 --- System Model --- p.44 / Chapter 4.4 --- Performance Modeling --- p.46 / Chapter 4.4.1 --- Continuous Time Markov Chain (CTMC) Model --- p.46 / Chapter 4.4.2 --- Fluid Flow Approximation (FFA) --- p.53 / Chapter 4.5 --- Conclusion on DTN with Node Heterogeneity --- p.73 / Chapter 5 --- Conclusion and Future Work --- p.75 / Chapter A --- Random Direction Mobility Model --- p.78 / Chapter A.1 --- Mean Inter-encounter Interval --- p.79 / Chapter A.2 --- Inter-encounter Interval Distribution --- p.86 / Chapter A.3 --- Concluding Remarks --- p.88 / Chapter B --- Additional Results by Fluid Flow Approximation and Moment Closure Methods --- p.92 / Bibliography --- p.96
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Resource allocation and throughput analysis for multi-radio multi-channel networks.January 2007 (has links)
Xu, Ceng. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (p. 68-71). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgement --- p.iii / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Motivation --- p.3 / Chapter 1.2 --- Contributions --- p.5 / Chapter 1.3 --- Thesis Scope --- p.5 / Chapter 2 --- Background Study --- p.6 / Chapter 2.1 --- Wireless Mesh Networks --- p.6 / Chapter 2.1.1 --- Overview of Wireless Mesh Networks --- p.6 / Chapter 2.1.2 --- Challenges of Wireless Mesh Networks --- p.9 / Chapter 2.1.3 --- Capacity Analysis of Wireless Mesh Net- works --- p.11 / Chapter 2.2 --- Network Coding --- p.13 / Chapter 2.2.1 --- Overview of Network Coding --- p.13 / Chapter 2.2.2 --- Network Coding in Wireless Networks --- p.17 / Chapter 3 --- Throughput Analysis --- p.19 / Chapter 3.1 --- Introduction --- p.19 / Chapter 3.2 --- Preliminaries --- p.20 / Chapter 3.3 --- Proof of Theorem 3.2.1 when n = m --- p.23 / Chapter 3.4 --- Proof of Theorem 3.2.1 when n≠ m --- p.36 / Chapter 3.4.1 --- Proof of Theorem 3.2.1 when m <n --- p.36 / Chapter 3.4.2 --- Proof of Theorem 3.2.1 when m > n --- p.37 / Chapter 3.5 --- Applying network coding into multi-radio multichannel networks --- p.37 / Chapter 3.6 --- Some simulation results --- p.40 / Chapter 3.6.1 --- String Topology --- p.40 / Chapter 3.6.2 --- Grid Topology --- p.41 / Chapter 3.6.3 --- Random Topology --- p.42 / Chapter 4 --- Interface Reduction in Wireless Mesh Networks --- p.43 / Chapter 4.1 --- Introduction --- p.43 / Chapter 4.2 --- Preliminaries --- p.44 / Chapter 4.2.1 --- Assumptions and Objectives of the Algorithm --- p.44 / Chapter 4.2.2 --- Definitions --- p.45 / Chapter 4.3 --- Steps of the Algorithm and an Example --- p.49 / Chapter 4.4 --- Simulation Results and Discussions --- p.53 / Chapter 4.5 --- Generalization --- p.54 / Chapter 5 --- Conclusion --- p.66 / Bibliography --- p.68
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Design and implementation of efficient routing protocols in delay tolerant networksUnknown Date (has links)
Delay tolerant networks (DTNs) are occasionally-connected networks that may suffer from frequent partitions. DTNs provide service despite long end to end delays or infrequent connectivity. One fundamental problem in DTNs is routing messages from their source to their destination. DTNs differ from the Internet in that disconnections are the norm instead of the exception. Representative DTNs include sensor-based networks using scheduled intermittent connectivity, terrestrial wireless networks that cannot ordinarily maintain end-to-end connectivity, satellite networks with moderate delays and periodic connectivity, underwater acoustic networks with moderate delays and frequent interruptions due to environmental factors, and vehicular networks with cyclic but nondeterministic connectivity. The focus of this dissertation is on routing protocols that send messages in DTNs. When no connected path exists between the source and the destination of the message, other nodes may relay the message to the destination. This dissertation covers routing protocols in DTNs with both deterministic and non-deterministic mobility respectively. In DTNs with deterministic and cyclic mobility, we proposed the first routing protocol that is both scalable and delivery guaranteed. In DTNs with non-deterministic mobility, numerous heuristic protocols are proposed to improve the routing performance. However, none of those can provide a theoretical optimization on a particular performance measurement. In this dissertation, two routing protocols for non-deterministic DTNs are proposed, which minimizes delay and maximizes delivery rate on different scenarios respectively. First, in DTNs with non-deterministic and cyclic mobility, an optimal single-copy forwarding protocol which minimizes delay is proposed. / In DTNs with non-deterministic mobility, an optimal multi-copy forwarding protocol is proposed. which maximizes delivery rate under the constraint that the number of copies per message is fixed . Simulation evaluations using both real and synthetic trace are conducted to compare the proposed protocols with the existing ones. / by Cong Liu. / Vita. / Thesis (Ph.D.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.
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Probabilistic predictor-based routing in disruption-tolerant networksUnknown Date (has links)
Disruption-Tolerant Networks (DTNs) are the networks comprised of a set of wireless nodes, and they experience unstable connectivity and frequent connection disruption because of the limitations of radio range, power, network density, device failure, and noise. DTNs are characterized by their lack of infrastructure, device limitation, and intermittent connectivity. Such characteristics make conventional wireless network routing protocols fail, as they are designed with the assumption the network stays connected. Thus, routing in DTNs becomes a challenging problem, due to the temporal scheduling element in a dynamic topology. One of the solutions is prediction-based, where nodes mobility is estimated with a history of observations. Then, the decision of forwarding messages during data delivery can be made with that predicted information. Current prediction-based routing protocols can be divided into two sub-categories in terms of that whether they are probability related: probabilistic and non-probabilistic. This dissertation focuses on the probabilistic prediction-based (PPB) routing schemes in DTNs. We find that most of these protocols are designed for a specified topology or scenario. So almost every protocol has some drawbacks when applied to a different scenario. Because every scenario has its own particular features, there could hardly exist a universal protocol which can suit all of the DTN scenarios. Based on the above motivation, we investigate and divide the current DTNs scenarios into three categories: Voronoi-based, landmark-based, and random moving DTNs. For each category, we design and implement a corresponding PPB routing protocol for either basic routing or a specified application with considering its unique features. / Specifically, we introduce a Predict and Relay routing protocol for Voronoi-based DTNs, present a single-copy and a multi-copy PPB routing protocol for landmark-based DTNs, and propose DRIP, a dynamic Voronoi region-based publish/subscribe protocol, to adapt publish/subscribe systems to random moving DTNs. New concepts, approaches, and algorithms are introduced during our work. / by Quan Yuan. / Vita. / Thesis (Ph.D.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.
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Optical multicast overlay and survivable architectures in high speed multi-wavelength optical access networks. / CUHK electronic theses & dissertations collectionJanuary 2011 (has links)
Nowadays, broadband applications, such as interactive video and multimedia services, have further increased the demand of bandwidth, and thus make high speed multi-wavelength optical access network highly desirable. Wavelength division multiplexing passive optical network (WDM-PON) is a promising candidate to realize the next generation optical access networks due to its dedicated bandwidth for each subscriber and more flexible bandwidth management. As the network traffic is becoming more data-centric, more networking capabilities are required to provide the data service in a more flexible and reliable way. In this thesis, we have proposed and investigated several interesting optical multicast overlay schemes and network protection architectures for WDM-PONs. Optical multicast overlay technique can support the additional multicast transmission on the existing point-to-point data services, while network protection architectures can assure network availability with short traffic restoration time. We will briefly discuss our work in the following sub-topics. / Optical multicast overlay in WDM-PON: Traditional WDM-PONs support only two-way point-to-point data transmission between the optical line terminal (OLT) and the individual subscribers, via the respective designated set of wavelengths. To enhance the network flexibility, it is more desirable to support various different modes of data or video delivery such as broadcast and multicast, in addition to point-to-point transmissions. In this thesis, we systematically investigate the problems and propose our several feasible schemes to overlay multicast transmission onto the existing point-to-point traffic in a WDM-PON. In the first approach, the control of the multicast transmission is achieved by a simple polarization-assisted scheme at the OLT. By the cross-use of wavelengths, a separate path is provided for the multicast differential phase shift keying (DPSK) data from downstream point-to-point amplitude shift keying (ASK) data without additional light sources, which guarantees the transmission performances in both directions, since the upstream ASK signal is imposed on the multicast DPSK signal. We have also demonstrated its variant, in which an optical switch replaces the polarization-assisted control for multicast transmission. The second approach is based on the optical carrier suppression (OCS) technique at the OLT so as to generate the optical subcarriers or sidebands for multicast ASK data modulation. The downstream unicast data is modulated in DPSK format, which will be re-modulated with the upstream ASK data at the respective optical network unit (ONU). As the downstream unicast signal and the upstream signal are calTied on different fiber feeders, while the upstream signal and the multicast signal are carried on different subcarriers, though on the same fiber feeder, the possible Rayleigh backscattering effect is much alleviated. In the third scheme, by using subcarrier modulation technique, we have first successfully overlaid two independent multicast data streams simultaneously onto a WDM-PON, which is believed to further enhance the network capability for multiple destination traffic and improve the cost effectiveness for the future network. Finally, we will provide a comprehensive comparison on all the proposed schemes in this topic. / Survivable network architectures for WDM-PONs: A survivable WDM-PON architecture which can provide self-protection is attractive to avoid enormous loss in data and business due to fiber cuts. To facilitate the network management, the protection switching is realized at the OLT. In this thesis, a simple centrally controlled survivable WDM-PON architecture employing OCS technique is proposed. Protection switching at the OLT employs electrical switches to control the clock signal for the protection sub-carrier generation, via optical carrier suppression. Both distribution and feeder fibers are protected simultaneously. By employing inverse-RZ (IRZ) format for the downstream transmission and non-retum-to-zero (NRZ) for the upstream re-modulated signal, the optical network units are kept colorless and simple. On the other hand, wavelength division multiplexing/time division multiplexing (WDM/TDM) hybrid network, which combines TDM technology and WDM technology, can further increase the network reach, transmission capacity, and reduces the cost per subscriber. Although the bandwidth per subscriber in a WDM/TDM PON is less than that in a WDM-PON, it is still considered as a smooth migration from TDM-PON to WDM-PON. In this thesis, we have proposed a novel WDM/TDM PON architecture which can provide self-protection using a ring topology to connect the subscribers. Finally, we will provide a comprehensive comparison on all the proposed schemes in this topic. / Qiu, Yang. / Adviser: Chun-Kit Chan. / Source: Dissertation Abstracts International, Volume: 73-06, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 130-140). / 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.
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Real-time multicast with scalable reliability.January 1998 (has links)
by Patrick C.K. Wu. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (leaves 57-[59]). / Abstract also in Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Research Objectives --- p.2 / Chapter 1.2 --- Organization of the Thesis --- p.2 / Chapter 2 --- Background --- p.4 / Chapter 2.1 --- Reliable Multicasting --- p.4 / Chapter 2.2 --- Related Work --- p.5 / Chapter 2.2.1 --- RMTP --- p.5 / Chapter 2.2.2 --- RMP --- p.6 / Chapter 2.2.3 --- RAMP --- p.7 / Chapter 2.3 --- Multicast with Scalable Reliability (MSR) --- p.8 / Chapter 3 --- Traffic Shaping in MSR --- p.10 / Chapter 3.1 --- Single Queue System --- p.11 / Chapter 3.2 --- Scaling factor α --- p.12 / Chapter 4 --- Retransmission Scheme in MSR --- p.15 / Chapter 4.1 --- Packet Loss Detection and Requests for Retransmission at the Receivers --- p.17 / Chapter 4.2 --- Retransmission at the Sender --- p.19 / Chapter 4.3 --- Dynamic Adjustment of Retransmission Timeout Value --- p.22 / Chapter 4.4 --- Scaling Reliability using Transmit-Display Window --- p.29 / Chapter 5 --- NACK Implosion Prevention --- p.31 / Chapter 5.1 --- Electing a Representative Receiver --- p.32 / Chapter 5.2 --- Determining T --- p.33 / Chapter 5.3 --- Determining β --- p.34 / Chapter 6 --- Performance Study of MSR --- p.38 / Chapter 6.1 --- Performance Study of MSR in Simple Network Topologies --- p.39 / Chapter 6.2 --- Star Topology --- p.40 / Chapter 6.3 --- Tree Topology --- p.44 / Chapter 6.4 --- Exploring the use of MSR Gateway --- p.47 / Chapter 7 --- Conclusion and Future Work --- p.50 / Chapter 7.1 --- Future Work --- p.50 / Chapter 7.2 --- Conclusions --- p.51 / Chapter A --- MSR Packet Formats --- p.52 / Chapter A.1 --- MSR Fixed Header --- p.52 / Chapter A.2 --- MSR Audio Data Header --- p.54 / Chapter A.3 --- MSR NACK Packets --- p.55 / Bibliography --- p.57
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