by Leung Yiu Tong. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 96-98). / Abstracts in English and Chinese. / Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Motivation --- p.1 / Chapter 1.2 --- Thesis Organization --- p.3 / Chapter 2. --- Storage Network Fundamentals --- p.4 / Chapter 2.1 --- Storage Network Topology --- p.4 / Chapter 2.1.1 --- Direct Attached Storage (DAS) --- p.5 / Chapter 2.1.2 --- Network Attached Storage (NAS) --- p.7 / Chapter 2.1.3 --- Storage Area Network (SAN) --- p.9 / Chapter 2.1.3.1 --- SAN and the Fibre Channel Protocol --- p.11 / Chapter 2.1.4 --- Summary on Storage Network Topology --- p.12 / Chapter 2.2 --- Storage Protocol --- p.15 / Chapter 2.2.1 --- Fibre Channel --- p.15 / Chapter 2.2.1.1 --- Fibre Channel over IP (FCIP) --- p.17 / Chapter 2.2.1.2 --- Internet Fibre Channel Protocol (iFCP) --- p.19 / Chapter 2.2.2 --- Internet SCSI (iSCSI) --- p.20 / Chapter 2.2.3 --- InfiniBand --- p.22 / Chapter 2.2.4 --- Review on Storage Network Protocol --- p.25 / Chapter 2.3 --- Standard Organization --- p.27 / Chapter 2.4 --- Summary --- p.28 / Chapter 3. --- Switching Design for Storage Networks --- p.30 / Chapter 3.1. --- Shared Bus Design --- p.32 / Chapter 3.2. --- Time Division Switch --- p.36 / Chapter 3.3. --- Share Buffer Memory Switch --- p.37 / Chapter 3.3.1 --- Parallel Memory Array --- p.40 / Chapter 3.3.2 --- Distributive Storage --- p.43 / Chapter 3.4. --- Crossbar Switch --- p.45 / Chapter 3.4.1 --- Arbitrated Crossbar vs. Buffered Crossbar --- p.46 / Chapter 3.4.1.1 --- Arbitrated Crossbar Switch --- p.47 / Chapter 3.4.1.2 --- Buffered Crossbar Switch --- p.48 / Chapter 3.4.2 --- Switch Scheduling --- p.49 / Chapter 3.4.2.1 --- Bipartite Matching --- p.50 / Chapter 3.4.2.2 --- Token-based Distributive Scheduling --- p.53 / Chapter 3.4.2.3 --- Resource Counting using Semaphore --- p.56 / Chapter 3.5. --- Algebraic Switches --- p.60 / Chapter 3.5.1 --- Switching by Conditionally Nonblocking Properties --- p.61 / Chapter 3.5.2 --- Self-Routing Mechanism with Zero-Bit Buffering --- p.64 / Chapter 3.5.3 --- Multistage Interconnection of Self-routing Concentrators --- p.69 / Chapter 3.6. --- Summary --- p.73 / Chapter 4. --- Investigating Switching Issue in Storage Networks --- p.74 / Chapter 4.1 --- Choosing a Suitable Switch --- p.74 / Chapter 4.2 --- Quality of Service (QoS) --- p.76 / Chapter 4.3 --- Multicasting --- p.77 / Chapter 4.3.1 --- Crossbar Switch --- p.78 / Chapter 4.3.2 --- Shared-Buffer Memory Switches --- p.80 / Chapter 4.3.3 --- Algebraic Switch --- p.82 / Chapter 4.3.4 --- Application on Multicast Transmission --- p.86 / Chapter 4.4 --- Load Balancing Mechanism --- p.87 / Chapter 4.5 --- Optimization on Storage Utilization --- p.91 / Chapter 4.6 --- Summary --- p.93 / Chapter 5. --- Conclusion and Summary of Original Contributions --- p.94

Application-layer overlay networks have recently emerged as a promising platform to deploy additional services over the Internet. A virtual network of overlay nodes can be used to regulate traffic flows of an underlay network, without modifying the underlay network infrastructure. As a result, an opportunity to redeem the inefficiency of IP routing and to improve end-to-end performance of the Internet has arisen, by routing traffic over multiple overlay paths. However, to achieve high end-to-end performance over the Internet by means of overlay networks, a number of challenging issues, including limited knowledge of the underlay network characteristics, fluctuations of overlay path performance, and interactions between overlay and the underlay traffic must be addressed. This thesis provides solutions to some of these issues, by proposing a framework to construct a multi-path overlay architecture for improving Internet end-to-end performance and availability. The framework is formed by posing a series of questions, including i) how to model and forecast overlay path performance characteristics; ii) how to route traffic optimally over multiple overlay paths; and iii) how to place overlay nodes to maximally leverage the Internet resource redundancy, while minimizing the deployment cost. To answer those research questions, analytical and experimental studies have been conducted. As a result, i) a loss model and a hybrid forecasting technique are proposed to capture, and subsequently predict end-to-end loss/delay behaviors; with this predictive capability, overlay agents can, for example, select overlay paths that potentially offer good performance and reliability; ii) to take full advantage of the predictive capability and the availability of multiple paths, a Markov Decision Process based multi-path traffic controller is developed, which can route traffic simultaneously over multiple overlay paths to optimize some performance measures, e.g. average loss rate and latency. As there can be multiple overlay controllers, competing for common resources by making selfish decisions, which could jeopardize performance of the networks, game theory is applied here to turn the competition into cooperation; as a consequence, the network performance is improved; iii) furthermore, to facilitate the deployment of the multi-path overlay architecture, a multi-objective genetic-based algorithm is introduced to place overlay nodes to attain a high level of overlay path diversity, while minimizing the number of overlay nodes to be deployed, and thus reducing the deployment cost. The findings of this thesis indicate that the use of multiple overlay paths can substantially improve end-to-end performance. They uncover the potential of multi-path application-layer overlay networks as an architecture for achieving high end-to-end performance and availability over the Internet.

The Resource Reservation Protocol (RSVP) is one of the proposals of the Internet Engineering Task Force (IETF) for conveying Quality of Service (QoS) related information in the form of resource reservations along the communication path. The RSVP specification (i.e. Request for Comments 2205) provides a narrative description of the protocol without any use of formal techniques. Thus, some parts of the document may be ambiguous, difficult to understand, and imprecise. So far, RSVP implementations have provided the only mechanism for validating. The cost for fixing errors in the protocol found in the implementation can be high. These disadvantages together with the fact that RSVP is complex make it a good target for formal specification and verification. This thesis formally defines the RSVP Service Specification, models RSVP using a formal method known as Coloured Petri Nets (CPNs) and attempts to verify the model. The following steps summarise the verification process of RSVP. Firstly, the RSVP service specification is derived from the protocol description and modelled using CPNs. After validating the model, the service language, which defines all the possible service primitive occurrence sequences, is generated from the state space of the model by using automata reduction techniques that preserve sequences. Secondly, RSVP is modelled using CPNs. The model is analysed for a set of behavioural properties. They include general properties of protocols, such as correct termination, and a set of new properties defined in this thesis, which are particular to RSVP. The analysis is based on the state space method. The properties are checked by querying the state graph and checking reachability among multiple nodes of its associated Strongly Connected Component (SCC) graph. As a first step, we analyse RSVP under the assumption of a perfect medium (no loss or duplication) to ensure that protocol errors are not hidden by rare events of the medium. The state space is reduced to obtain the sequences of service primitives allowed by RSVP known as the protocol language. Then, the protocol language is compared with the service language to determine if they are equivalent. The desired properties of RSVP are proved to be satisfied by the RSVP CPN model, so that the features of RSVP included in the CPN model operate as expected under our modelling and analysis assumptions. Also, the language analysis results show that RSVP service primitive occurrence sequences generated by the RSVP model are included in the proposed model of the service specification. However, some service primitive occurrence sequences generated from the service specification model are not in the protocol language. These sequences were analysed. There is strong evidence to suggest that these sequences would also appear in the protocol if the capacity of the medium in the RSVP model was marginally increased. Unfortunately, the standard reachability analysis tools would not handle this case, due to state space explosion. / Thesis (PhD)--University of South Australia, 2003

Although the Internet is the dominant broadband network, it still has a fundamental shortcoming in traffic management that does not properly support efficient use of resources together with differentiated quality of service for mixed traffic types. Even though a number of mechanisms have been proposed under key approaches of resource adaptation, resource reservation, and resource pricing, this problem remains unsolved to date because of its complexity and the way it relates to so many considerations of engineering and economics, and the diverse range of services desired by users. Hence it is considered difficult to devise a perfect mechanism that can universally solve this problem. In this respect, this dissertation contributes to insights into potential combinations and trade-offs of key approaches above in some efficient manner for managing traffic and scarce resources in the Internet. The first part of this work considers the combination of relaxed resource reservation and resource pricing schemes for handling the unfair bandwidth distribution problem in soft-bandwidth guarantee services of the Differentiated Services (DiffServ) Internet. We show that this unfairness problem can be handled using a network-user cooperative approach that addresses both individual user satisfaction and global optimization. We propose to add a mechanism based on price-based feedback signaling to DiffServ-capable routers providing Assured Forwarding (AF) Service so that they can offer per-flow signaling. This still allows them to work at an aggregate traffic level, hence the scalability feature of the DiffServ network can be retained. Our proposed mechanism allows the network to offer reliable service assurances via a distributed optimization algorithm, without introducing special protocols or requiring routers to have access of individual user requirements. Moreover, it can provide incentives for users to cooperate so that optimum performance can be accomplished. This approach has broad applicability and is relevant to all types of assured service classes. The second part of this work considers the combination of a specific resource pricing scheme based on a distributed optimization algorithm and multimedia adaptation schemes. Such a capability has not been available because most utility functions of multimedia applications do not meet the concavity constraints required by optimization algorithm. We proposed to overcome this limitation by redefining user utility functions into equivalent discrete forms and using combinatorial (discrete) optimization so that interfacing the resource-pricing scheme can be done in a normal way. However, to obtain feasible solutions in a scalable manner, an agent is included into the scheme for solving the combinatorial (discrete) optimization on behalf of a small group of users. In return, all users belonging to this group can benefit from social welfare maximization of their utilities over a network resource constraint. The last part of this work considers the combination of relaxed resource reservation and resource pricing schemes to enable a proper charging scheme for adaptive applications in the DiffServ Internet. We provide an optimization formulation of the problems of revenue and social welfare maximization, applied at a service provider (SP) who gives access to the DiffServ Internet. In this scheme, resources are provisioned per QoS-oriented class in a long time scale (service level agreement (SLA) duration), then priced based on user demand in the short time scale. We also show that the proposed charging scheme can provide feedback and incentives for users to use the network resource optimally via the standard packet marking, hence eliminating the need for specific pricing protocol. All of the proposals in this work can be used together, solving these key problems as a coordinated whole, and all use readily available network mechanisms.

The focus of this thesis is on the resource allocation problems in wireless sensor and cooperative networks. Typically, wireless sensor networks operate with limited energy and bandwidth are often required to meet some specified Quality-of-Service (QoS) constraints. The ultimate objective for the majority of the problems considered in this thesis is to save battery energy and maximize the network lifetime. / In the first part of this thesis, we employ complex mathematical models to emulate a variety of power drains in wireless sensor nodes. In the first instance, we address a lifetime optimization problem of a wireless TDMA/CDMA sensor network for joint transmit power and rate allocations. The effect of fast fading is captured by including rate outage and link outage constraints on each link. After that, a single-hop wireless sensor network is deployed for a certain application - to estimate a Gaussian source within a pre-specified distortion threshold. In this part, we consider lifetime maximization, in different multiple access protocols such as TDMA, an interference limited non-orthogonal multiple access (NOMA) and an idealized Gaussian multiple access channel. This problem is further studied in a multi-hop scenario where sensing and receiving powers are also included in addition to transmission power. Finally, we investigate a balancing problem between the source coding and transmission power for video wireless sensor systems where the sensor node is required to send the collected video clips, through wireless media, to a base station within a corresponding distortion threshold. All these energy saving and lifetime optimization problems in sensor networks can be formulated via nonlinear nonconvex optimization problems, which are generally hard to solve. However, with favourable variable substitution and reasonable approximation, most of these problems are shown to be convex. The only exception is the Gaussian source esitmation problem in NOMA scenario for which we provide a simple successive convex approximation based algorithm for the NOMA case that converges fast to a suboptimal solution. / In the second part of the thesis, we propose an optimal power allocation scheme with a K-block coding delay constraint on data transmission using a three node cooperative relay network assuming a block fading channel model. Channel information is fed back to the transmitter only in a causal fashion, so that the optimal power allocation strategy is only based on the current and past channel gains. We consider the two simplest schemes for information transmission using a three node (a source, a relay and a destination) relay network, namely the amplify and forward (AF) and decode and forward (DF) protocols. We use the dynamic programming methodology to solve the (K-block delay constrained) expected capacity maximization problem and the outage probability minimization problem with a short term sum power (total transmission power of the source and the relay) constraint. / The main contribution of the thesis is a comprehensive suite of power minimization and lifetime maximization methods that can be used in wireless sensor networks. We present several such applications and extensive numerical examples at the end of each chapter.

Ad Hoc networks are multi-hop wireless networks consisting of mobile hosts. They do not have any pre-existing network infrastructure and are characterized by constantly changing topology, limited battery power and bandwidth. Typical applications of such networks are battlefield networks, medical relief during natural calamities or disasters, conference room networking, and intra-vehicular communications. Routing packets in an ad-hoc network is a challenge because of the mobile nature of the nodes and the constantly changing topology. In ad hoc networks, each mobile node functions as a router, forwarding packets, establishing routes and helping each other in maintaining the network. A novel scalable routing protocol SLURP (Scalable Location Updated-based Routing Protocol) addresses these issues of ad hoc networks routing. The protocol is based on a location management strategy, which keeps the routing overhead to a minimum. In this thesis we compare the protocol against an existing set of multi-hop ad hoc network routing protocols that cover a range of design choices: DSDV, TORA, DSR, and AODV. We implemented SLURP in the network simulator ns-2, with the necessary wireless extensions. Experiments were run to simulate changes in network topology, number of active sources, link connectivity, and speed of motion. The difference in performance and scalability are illustrated. / Graduation date: 2003

Thesis (M.S.)--Brigham Young University. Dept. of Electrical and Computer Engineering, 2006. / Includes bibliographical references (p. 225-229).

Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 175-177).

Thesis (Ph. D.)--State University of New York at Binghamton, Department of Computer Science, 2005. / Includes bibliographical references (p. 129-136).

Thesis (Ph.D. (Computer Science)) - Rhodes University, 2008.