Midterm-5106-Su10-Last-page

Midterm-5106-Su10-Last-page - β *|SampleRTT –...

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Name or Student ID: ________________________________ 1 Useful formulae: [Note that you may not need all of these formulae. Use as needed] Utilization: - - , S=2x10 8 m/s - For stop-and-wait: , where p is the probability that a frame is in error. Utilization for sliding-window mechanisms with window of w: - Go back N: , if w fills the pipe, or otherwise - Selective repeat: , if w fills the pipe, or otherwise - M/D/1: queuing delay ; Ts is service time & ρ is link utilization - M/D/1: average queue length or buffer occupancy - M/M/1: queuing delay , buffer occupancy: - TCP: - slow start CongWin+=1 per ACK, - congestion avoidance CongWin+=1 per RTT, - EstimatedRTT(k)= (1- α )*EstimatedRTT(k-1) + α *SampleRTT(k), 0< α <1 - DevRTT= (1- β )*DevRTT+
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Unformatted text preview: β *|SampleRTT – EstimatedRTT|, 0< β <1 -TimeoutInterval = EstimatedRTT + 4*DevRTT ATM ABR rate-based congestion control: -Increase: Rate = min(PCR, Rate + PCR x RIF) -Decrease: Rate = max(MCR, min[ER, Rate – Rate x RDF]) Probability distributions and stochastic processes: -Geometric distribution: x is the number of Bernoulli experiments until success, Pr[X=k]=q k-1 p, E(X)=1/p -Binomial distribution: x is the number of successes in n Bernoulli experiments/trials , E[X]=np Name or Student ID: ________________________________ 2-Poisson Distribution: Pr[X=k]= ( λ k /k!) e-λ ,E[X]=Var[X]= λ-Exponential distribution: f(x)= λ e-λ x , F[x]=1-e-λ x , Pr[X>x]=1-F[x]=e-λ x , E[X]=1/ λ...
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This document was uploaded on 05/27/2011.

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Midterm-5106-Su10-Last-page - β *|SampleRTT –...

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