2,564 research outputs found
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Improving the network transmission cost of differentiated web services
This paper investigates into the transmission cost of web services related messages which is affected by network
latency. Web services enable seamless interaction and integration of e-business applications. Web services contain a
collection of operations so as to interact with outside world over the Internet through XML messaging. Though XML
effectively describe message related information and is fairly human readable, it badly affects the performance of Web
services in terms of transmission cost, processing cost, and so on. This paper aims to minimize network latency of message
communication of Web services by employing pre-emptive resume scheduling. Fundamental principle of this approach is the
provision of preferential treatment to some messages as compared to others. This approach assigns different priorities to
distinct classes of messages given the fact that some messages may tolerate longer delays than others. For instance, shorter
messages may be given higher priority than longer messages, or the Web service provider may give higher priority to the
messages of paying subscribers
Information Switching Processor (ISP) contention analysis and control
Future satellite communications, as a viable means of communications and an alternative to terrestrial networks, demand flexibility and low end-user cost. On-board switching/processing satellites potentially provide these features, allowing flexible interconnection among multiple spot beams, direct to the user communications services using very small aperture terminals (VSAT's), independent uplink and downlink access/transmission system designs optimized to user's traffic requirements, efficient TDM downlink transmission, and better link performance. A flexible switching system on the satellite in conjunction with low-cost user terminals will likely benefit future satellite network users
Introduction to Queueing Theory and Stochastic Teletraffic Models
The aim of this textbook is to provide students with basic knowledge of
stochastic models that may apply to telecommunications research areas, such as
traffic modelling, resource provisioning and traffic management. These study
areas are often collectively called teletraffic. This book assumes prior
knowledge of a programming language, mathematics, probability and stochastic
processes normally taught in an electrical engineering course. For students who
have some but not sufficiently strong background in probability and stochastic
processes, we provide, in the first few chapters, background on the relevant
concepts in these areas.Comment: 298 page
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Computing infrastructure issues in distributed communications systems : a survey of operating system transport system architectures
The performance of distributed applications (such as file transfer, remote login, tele-conferencing, full-motion video, and scientific visualization) is influenced by several factors that interact in complex ways. In particular, application performance is significantly affected both by communication infrastructure factors and computing infrastructure factors. Several communication infrastructure factors include channel speed, bit-error rate, and congestion at intermediate switching nodes. Computing infrastructure factors include (among other things) both protocol processing activities (such as connection management, flow control, error detection, and retransmission) and general operating system factors (such as memory latency, CPU speed, interrupt and context switching overhead, process architecture, and message buffering). Due to a several orders of magnitude increase in network channel speed and an increase in application diversity, performance bottlenecks are shifting from the network factors to the transport system factors.This paper defines an abstraction called an "Operating System Transport System Architecture" (OSTSA) that is used to classify the major components and services in the computing infrastructure. End-to-end network protocols such as TCP, TP4, VMTP, XTP, and Delta-t typically run on general-purpose computers, where they utilize various operating system resources such as processors, virtual memory, and network controllers. The OSTSA provides services that integrate these resources to support distributed applications running on local and wide area networks.A taxonomy is presented to evaluate OSTSAs in terms of their support for protocol processing activities. We use this taxonomy to compare and contrast five general-purpose commercial and experimental operating systems including System V UNIX, BSD UNIX, the x-kernel, Choices, and Xinu
Optimal Hyper-Scalable Load Balancing with a Strict Queue Limit
Load balancing plays a critical role in efficiently dispatching jobs in
parallel-server systems such as cloud networks and data centers. A fundamental
challenge in the design of load balancing algorithms is to achieve an optimal
trade-off between delay performance and implementation overhead (e.g.
communication or memory usage). This trade-off has primarily been studied so
far from the angle of the amount of overhead required to achieve asymptotically
optimal performance, particularly vanishing delay in large-scale systems. In
contrast, in the present paper, we focus on an arbitrarily sparse communication
budget, possibly well below the minimum requirement for vanishing delay,
referred to as the hyper-scalable operating region. Furthermore, jobs may only
be admitted when a specific limit on the queue position of the job can be
guaranteed.
The centerpiece of our analysis is a universal upper bound for the achievable
throughput of any dispatcher-driven algorithm for a given communication budget
and queue limit. We also propose a specific hyper-scalable scheme which can
operate at any given message rate and enforce any given queue limit, while
allowing the server states to be captured via a closed product-form network, in
which servers act as customers traversing various nodes. The product-form
distribution is leveraged to prove that the bound is tight and that the
proposed hyper-scalable scheme is throughput-optimal in a many-server regime
given the communication and queue limit constraints. Extensive simulation
experiments are conducted to illustrate the results
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