In conventional multicast communication, the source carries a single conversation with all destination nodes. If a node on the path to any destination becomes congested the throughput to all destinations is reduced, t...
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In conventional multicast communication, the source carries a single conversation with all destination nodes. If a node on the path to any destination becomes congested the throughput to all destinations is reduced, thus treating same destination nodes unfairly. We consider a window-controlled multipoint connection and study the use of destination set grouping, where the destination set can be split into disjoint subgroups with the source carrying independent conversations with each subgroup. We present a dynamic grouping protocol which can adjust the grouping and the window sizes per group in response to changing network conditions. The performance of the protocol is studied using simulation and compared with single-group multicasting.
The object of this paper is to explore the behaviour of a TCP connection in presence of exogenous non-controlled traffic and to study the impact of TCP operation on the performance as seen by this traffic. General equ...
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The object of this paper is to explore the behaviour of a TCP connection in presence of exogenous non-controlled traffic and to study the impact of TCP operation on the performance as seen by this traffic. General equations for the queue state evolution are derived and an explicit solution is given for constant rate traffic. Such a model applies to video or sound exogenous traffic and may give an insight on the phenomena for random traffic for certain network configurations (large buffers, low traffic variance). The performance criteria evaluated are TCP throughput, buffer occupancy distribution and evolution in time, packet loss rates and frequency of loss periods.
This paper presents extensions to a technique for specifying and analyzing nonmonotonic cryptographic protocols (NCP) that use asymmetric keys. We introduce new actions and inference rules, as well as slight modificat...
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This paper presents extensions to a technique for specifying and analyzing nonmonotonic cryptographic protocols (NCP) that use asymmetric keys. We introduce new actions and inference rules, as well as slight modifications to the update function. An important observation is that reasoning about the origin of messages is quite different when dealing with asymmetric key protocols. We also introduce the notion that keys in certificates should be bound to the principals receiving them. We extend the technique to meet the binding requirements and show how the flaw in the Denning and Sacco (1981) public key protocol, that was discovered by Abadi and Needham (1994), is revealed. We demonstrate the extended technique using one protocol of our own and the Needham and Schroeder (1978) public key protocol. Finally, we introduce and analyze a fix to a known weakness in Needham and Schroeder's protocol using our extended technique.
Multiprotocol systems can be an important tool for achieving interoperability. As the number of protocols available on such systems grows, there is an increasing need for support mechanisms that enable users to effect...
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Multiprotocol systems can be an important tool for achieving interoperability. As the number of protocols available on such systems grows, there is an increasing need for support mechanisms that enable users to effectively access these protocols. Of particular importance is the need to determine which of several protocols to use for a given communication task. In this work, we propose architectures for a protocol discovery system that uses protocol feedback mechanisms to determine which protocols are supported. We describe the issues related to protocol discovery and present feedback mechanisms necessary to support discovery. We present a prototype implementation of a discovery system that supports multiple protocols.
This paper proposes and discusses a simulation model of a message and transaction queuing protocol which supports submission of transactions from mobile workstations in a distributed multidatabase environment. The mod...
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This paper proposes and discusses a simulation model of a message and transaction queuing protocol which supports submission of transactions from mobile workstations in a distributed multidatabase environment. The model is based on coloured Petri nets formalism. A hierarchical coloured Petri nets model describing the two key components of the protocol, namely message queuing facility and transaction queuing facility, is constructed and analyzed using the software tool Design/CPN. Simulation of message and transaction processing algorithms has been carried out to verify and refine the design of the proposed protocol. The tool has also enabled us to assess the practicality of the developed approach and study the impact of the protocol implementation. Finally, the results of simulation are analysed and discussed.
This paper evaluates the concept of virtual path (VP) policing as an alternative to virtual channel (VC) policing in an asynchronous transfer mode (ATM) Ethernet network. The usage parameter control (UPC) function inc...
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This paper evaluates the concept of virtual path (VP) policing as an alternative to virtual channel (VC) policing in an asynchronous transfer mode (ATM) Ethernet network. The usage parameter control (UPC) function includes a peak rate and a sustainable rate policer. Both policers are implemented based on the leaky bucket algorithm defined by the ATM Forum. We implement VC and VP policers in parallel in a configuration containing variable bit rate (VBR) traffic VCs multiplexed in a VP. Simulations are used to measure the level of noncompliant traffic declared by the UPC function of both the VC and VP policing units. We evaluate the fairness of VP policing by having one group of VCs generate traffic in excess of their allocated bandwidth. We conclude that VP policing does not protect compliant VCs from non-compliant VCs. In fact, simulation results show that VP policing encourages cheating by penalizing compliant users more than non-compliant users.
This paper presents a unified model for analyzing multistage interconnection networks with multi-queue buffered strategies. Buffering strategies include SAFC (statically allocated fully connected), SAMQ (statically al...
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This paper presents a unified model for analyzing multistage interconnection networks with multi-queue buffered strategies. Buffering strategies include SAFC (statically allocated fully connected), SAMQ (statically allocated multi-queue), DAMQ (dynamically allocated multi-queue), and DAFC (dynamically allocated fully connected) schemes. We develop a unified model to evaluate the performance of all these buffer allocation schemes under both uniform and nonuniform traffic patterns. The analytical model is validated through extensive simulations. Using the unified model, we conducted performance comparisons on the four buffer allocation schemes. It is shown that the DAFC scheme has the best performance over all the four buffer allocation schemes under both uniform and nonuniform loads.
This comprehensive textbook/reference presents a focused review of the state of the art in privacy research, encompassing a range of diverse topics. The first book of its kind designed specifically to cater to courses...
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ISBN:
(数字)9783319084701
ISBN:
(纸本)9783319084695;9783319356310
This comprehensive textbook/reference presents a focused review of the state of the art in privacy research, encompassing a range of diverse topics. The first book of its kind designed specifically to cater to courses on privacy, this authoritative volume provides technical, legal, and ethical perspectives on privacy issues from a global selection of renowned experts. Features: examines privacy issues relating to databases, P2P networks, big data technologies, social networks, and digital information networks; describes the challenges of addressing privacy concerns in various areas; reviews topics of privacy in electronic health systems, smart grid technology, vehicular ad-hoc networks, mobile devices, location-based systems, and crowdsourcing platforms; investigates approaches for protecting privacy in cloud applications; discusses the regulation of personal information disclosure and the privacy of individuals; presents the tools and the evidence to better understand consumers’ privacy behaviors.
This book presents research from many of the major projects involved in the emerging global grid infrastructure. With a particular focus on the practical advantages and applications of grid computing – includin...
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ISBN:
(数字)9780857296764
ISBN:
(纸本)9780857296757;9781447126690
This book presents research from many of the major projects involved in the emerging global grid infrastructure. With a particular focus on the practical advantages and applications of grid computing – including real case studies – the book provides an in-depth study of grid technology for a wide range of different needs. Topics: examines a remote instrumentation infrastructure, and a methodology to support e-science applications on e-infrastructures; describes the GEMS storage system, and pipeline workflows for optimizing end-to-end performance in wide-area networks; investigates semantic grid system architecture, social grid agents, and monitoring platforms designed for large-scale distributed systems; explores job control using service-level agreements; introduces the Composable Services Architecture for dynamic service provisioning, and the semantically driven communication middleware platform, Phoenix; discusses the PhyloGrid application, and a numerical simulation performed using grid computing.
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