155 research outputs found
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
Improving the fairness of FAST TCP to new flows
It has been observed that FAST TCP, and the related protocol TCP Vegas, suffer unfairness when many flows arrive at a single bottleneck link, without intervening departures. We show that the effect is even more marked if a new flow arrives when existing flows share bandwidth fairly, and propose a simple method to ameliorate this effect
Sizes of Minimum Connected Dominating Sets of a Class of Wireless Sensor Networks
We consider an important performance measure of wireless sensor networks, namely, the least number of nodes, N, required to facilitate routing between any pair of nodes, allowing other nodes to remain in sleep mode in order to conserve energy. We derive the expected value and the distribution of N for single dimensional dense networks
A Study of a Loss System with Priorities
The Erlang loss formula, also known as the Erlang B formula, has been known
for over a century and has been used in a wide range of applications, from
telephony to hospital intensive care unit management. It provides the blocking
probability of arriving customers to a loss system involving a finite number of
servers without a waiting room. Because of the need to introduce priorities in
many services, an extension of the Erlang B formula to the case of a loss
system with preemptive priority is valuable and essential. This paper
analytically establishes the consistency between the global balance (steady
state) equations for a loss system with preemptive priorities and a known
result obtained using traffic loss arguments for the same problem. This paper,
for the first time, derives this known result directly from the global balance
equations based on the relevant multidimensional Markov chain. The paper also
addresses the question of whether or not the well-known insensitivity property
of the Erlang loss system is also applicable to the case of a loss system with
preemptive priorities, provides explanations, and demonstrates through
simulations that, except for the blocking probability of the highest priority
customers, the blocking probabilities of the other customers are sensitive to
the holding time distributions and that a higher variance of the service time
distribution leads to a lower blocking probability of the lower priority
traffic
Automatic laser shutdown implications for all optical data networks
Generalized multiprotocol label switching (GMPLS), optical packet, and burst-switched networks in which the synchronous digital hierarchy/synchronous optical network (SDH/SONET) layer is removed may be rendered nonfunctional because the current standard for triggering Automatic Power Reduction (APR) cannot distinguish between a fiber that has been de-energized and a fiber failure. If this standard is applied, without modification, the likelihood of unnecessary amplifier shutdown in optical networks is significant. These shutdown events may impact large regions of the network and render optical links inoperable. To avoid unnecessary amplifier shutdown, amendments to the current operation of APR are suggested
Meeting connectivity requirements in a wireless multihop network
This paper investigates the connectivity probability of 1-dimensional ad hoc networks in which nodes have random, non-identically distributed locations, this leads to optimization of the number of nodes required. An empirical approach is used. We fit a parametric distribution to the CDF of the maximum distance between adjacent nodes. Special and extreme cases which are not covered by the empirical approach are treated separately
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