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# 《第二章 通信网络业务模型》.pdf

 Traffic models have played a significant role in the design and engineering of
circuit-switched and packet-switched network.
 In particular, Poisson arrival and exponential call-holding time statistics have
served as excellent models for almost a century in carrying out both the
engineering and performance evaluation of circuit-switched voice telephony.
Poisson arrival and relatively simple, packet-length models have been used
extensively in studying the performance of packet-switched networks as well.

 It appears that the integration of packetized voice, packetized video, packetized
images, and computer-generated data traffic (whether brief bursts or much longer
file transfers), each with its own multi-objective quality of service, requires the
development of rather sophisticated traffic models to carry out accurate design
and performance evaluation.

• Broadband integrated networks, Chapter 2

• 西电刘增基教授《宽带异步接入》课件

2.1 典型的随机过程

• A stochastic process  A  t  t  0  taking nonnegative integer values is said
to be a Poisson process with rate l if

– 1) A(t) is a counting process that represents the total number of arrivals that have
occurred from 0 to time t [i.e., A(0)=0], and for s<t, A(t)-A(s) equals the numbers of
arrivals in the interval (s,t].

– 2) The number of arrivals that occur in disjoint time intervals are independent.

– 3) The number of arrivals in any interval of length t is Poisson distributed with

parameter lt. That is, for all t, t > 0, Bursts
n Source
lt 
P A t+t  - A ( t )= n = e-lt , n =0,1,
n!

# 《第二章 通信网络业务模型》.pdf

《第二章 通信网络业务模型》.pdf