Midterm-5106-Su10-Last-page

Midterm-5106-Su10-Last-page - 0<...

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Name or Student ID: ________________________________ Useful formulae: [Note that you may not need all of these formulae. Use as needed] Utilization: - onDelay transmissi nDelay propagatio Trans Tprop a = = - S ce Dis nDelay propagatio tan = , S=2x10 8 m/s - For stop-and-wait: ) 2 1 ( 1 a p u + - = , where p is the probability that a frame is in error. Utilization for sliding-window mechanisms with window of w: - Go back N: ap p u 2 1 1 + - = , if w fills the pipe, or ) 1 )( 2 1 ( ) 1 ( wp p a p w u + - + - = otherwise - Selective repeat: ) 1 ( p u - = , if w fills the pipe, or ) 2 1 ( ) 1 ( a p w u + - = otherwise - M/D/1: queuing delay ) 1 .( 2 ) 2 ( ρ - - = Ts Tq ; Ts is service time & ρ is link utilization - M/D/1: average queue length or buffer occupancy ) 1 .( 2 . 2 λ - + = = Tq q - M/M/1: queuing delay ) 1 ( - = Ts Tq , buffer occupancy: ) 1 ( - = q - 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+ β*|SampleRTT – EstimatedRTT|,
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Unformatted text preview: 0&lt; &lt;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 ( 29 ( 29 ! )! ( ! , ) ( k k n n k X P n k k k n n k p q-= = =-, E[X]=np 1 Name or Student ID: ________________________________-Poisson Distribution: Pr[X=k]= ( k /k!) e- ,E[X]=Var[X]= -Exponential distribution: f(x)= e- x , F[x]=1-e- x , Pr[X&gt;x]=1-F[x]=e- x , E[X]=1/ 2...
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Midterm-5106-Su10-Last-page - 0&amp;amp;lt;...

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