Used for analyzing network performance In packet networks, events are random Random packet arrivals Random packet lengths While at the physical layer we were concerned with bit-error-rate, at the network layer we care about delays How long does a packet spend waiting in buffers?
flow networks Definition. A flow network is a directed graph G=(, E)with two distinguished vertices:a source s and a sink t. Each edge(u, v)E E has a nonnegative capacity c(u, v). If(u, v) E, then c(u, v)=0 Example: c 2001 by Charles E Leiserson
An interesting property of an M/M/ 1 queue, which greatly simplifies combining these queues into a network, is the surprising fact that the output of an M/M/ queue with arrival rate is a Poisson process of rate This is part of Burke's theorem, which follows from reversibility A Markov chain has the property that P[future present, past] P[future present] Conditional on the present state, future states and past states are independent
The provision of mass media content over next-generation 3G mobile networks is envi- sioned as an exciting new application of new media. This paper focuses on the mobile Internet as strategic challenge for media and entertainment companies. It provides an overview of distinctive features of the mobile Internet related to personalization, time and location sensitivity, uncertainties b echnology push and market pull, and motiva- tions for engagemer