计算机网络性能分析network

NetworkDesignand GraduatGraduatUniversit,NetworkDesign ysis-----Wang

QueueingTheoryGraduatUniversit,NetworkDesignandGraduatUniversit,

M/G/1ResidualLife GraduatUniversit,MethodofImbeddedMarkovNetworkDesign ysis-----Wang

M/G/1M/Msystemsverytractableduetomemorylesspropertyofinrrival&servicetimesTheM/G/1systemallowsforageneralservicetimedistribution,insteadofthemorerestrictiveexponentialservicetime.GraduatUniversit,ArrivalsarerestrictedtobePoisson,withrateGraduatUniversit,TheM/G/1systemhasmanypracticalTheservicetimemaybeaconstant,oruniformlyTheservicetimemaybeacombinationoftwoormoreexponentiallydistributedtimes NetworkDesign ysis-----Wang

M/G/1假定第i个用户的服务时间为Xi,Xi是独立、同分布的任意分布函数并且与到达间隔相互独立。令X=｛X1,X2,｝则服GraduatGraduatUniversit, NetworkDesign ysis-----Wang

MethodsforIngeneral,therearetwo ResidualLifeApproach（MeanResidualServiceTime）:ThisiseasytousebutcanonlygivethemeanvaluesofthedesiredparametersMethodofImbeddedMarkovGraduatUniversit,ThisisbasedonfindingasetofatimepointswheretheMarkovianPropertyisretained.ThisisgenerallyhardertousebutwillgivethedistributionofGraduatUniversit,NetworkDesignandysis-----Wang

M/G/1ResidualLife GraduatUniversit,MethodofImbeddedMarkovNetworkDesign ysis-----Wang

ResidualLife GraduatUniversit,X1,X2…GraduatUniversit,，则NetworkDesign ysis-----Wang

P- GraduatUniversitGraduatUniversit,NetworkDesign ysis-----Wang

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P- 即使ρ＜1,如果X2→∞,则W→∞。GraduatUniversit,GraduatUniversit,NetworkDesignandysis-----Wang

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Poisson过程,分组(帧)⻓度相同,为⼀个单位,等待应答的最⻓时间(重传间隔)为n-1个分组⻓度。因此任GraduatUniversit,GraduatUniversit,M/G/1ResidualLife GraduatUniversit,MethodofImbeddedMarkovNetworkDesign ysis-----Wang

有 队列 储数据、信令交换等)GraduatUniversit,GraduatUniversit,NetworkDesignandysis-----Wang

有 队列量,并且与到达间隔相互独立,其均值为V。 量,其平均服务时间为1/μ。GraduatUniversitGraduatUniversit,NetworkDesignandysis-----Wang

有 队列GraduatUniversit,NetworkDesignGraduatUniversit,

有 队列GraduatUniversit,NetworkDesignGraduatUniversit,

有 队列则在单位时间,分组所占的比例为λ/μ=ρ,休假期占的GraduatUniversitGraduatUniversit,使用P-KNetworkDesign ysis-----Wang

EX-2时隙M/D/1GraduatUniversit,NetworkDesignandGraduatUniversit,

EX-3FDM和TDM系统的性能比较(FrequencyDivisionMultiplexing)复用m个子信道,总的分组到GraduatUniversit,GraduatUniversit,在该系统中,只要分组到达时,信道空闲,该分组就会立即得到服务。显然每个信道是标准的M/D/1排队系统,其等待时间为NetworkDesignandysis-----Wang

EX-3FDM和TDM系统的性能比较GraduatGraduatUniversit,NetworkDesignandysis-----Wang

EX-3FDM和TDM系统的性能比较 GraduatUniversit, GraduatUniversit,NetworkDesign ysis-----Wang

EX-3FDM和TDM系统的性能比较对TDM系统一帧由m个时隙组成每个时隙传输一个分组时GraduatUniversit,隙才可能开始传输分组。因此,对于每个用户来说,信道将暂GraduatUniversit,在TDM系统中,剩余服务时间与SFDM系统的完全相同,即当个时隙的剩余时间,而是一帧中的剩余时间,NetworkDesignandysis-----Wang

EX-3FDM和TDM系统的性能比较GraduatUniversit,NetworkDesignandGraduatUniversit,

EX-3FDM和TDM系统的性能比较aaysaaaysajGraduatUniversit,

M/G/1ResidualLife GraduatUniversit,MethodofImbeddedMarkovNetworkDesign ysis-----Wang

有优先级的队列流具有最高优先级,第2类的分组流具有次高优先级,GraduatUniversit,为λ1,λ2,…,λn, 服务时间分别为1/μ1,1/μ2,…,1/GraduatUniversit,NetworkDesignandysis-----Wang

有优先级的队列NonpreemptivePriority）GraduatUniversit,GraduatUniversit,NetworkDesignandysis-----Wang

非强占优先级r1+r2++ <1设平均剩余服务时间为RP-GraduatUniversitGraduatUniversit,

1Q11W=R+1N1=R+ lW1=R+r1Q11 WW1=1-NetworkDesign

ysis-----Wang

非强占优先级GraduatUniversit,GraduatUniversit,NetworkDesign ysis-----Wang

非强占优先级GraduatUniversit, Rk(1-r1-r2--)(1-r1--rkysis-----Wangysis-----Wang 非强占优先级GraduatUniversit,== nl 2 T=1kmkkysis-----Wangysis-----Wang 非强占优先级TT=1+l2T2++GraduatGraduatUniversit,ysis-----Wangysis-----Wang 非强占优先级GraduatUniversit,GraduatUniversit,如果μA>μB,则应给A分配较高的优先级,利⽤T的表达式,可NetworkDesignandysis-----Wang

强占优先级GraduatUniversit,组通常被分成若干个ATM信元。当正在传输⼀个低优先级分组的ATM信元流时,有⼀个高优先级分组到达,这时将暂停低优先级分组的GraduatUniversit,NetworkDesignandysis-----Wang

强占优先级

GraduatUniversit,到达的第k优先级顾客的平均等待时间包括两部1到kGraduatUniversit, NetworkDesignandysis-----Wang

GraduatUniversitGraduatUniversit,可以按照普通的无优先级M/G/1队列来求解，其NetworkDesignandysis-----Wang

强占优先级GraduatUniversit,NetworkDesignandGraduatUniversit,

强占优先级GraduatUniversit,NetworkDesignandGraduatUniversit,

M/G/1ResidualLife GraduatUniversit,MethodofImbeddedMarkovNetworkDesign ysis-----Wang

在M/G/1排队系统中，到达过程是平均到达速率为l的 GraduatUniversitGraduatUniversit,NetworkDesign ysis-----Wang

GraduatUniversit,具有无性）以及服务过程（不必无）都是重新开始NetworkDesign ysis-----Wang

GraduatUniversit,NetworkDesignandysis-----Wang

Ni表示第i个客户完成服务之后队列中的客户数（不包括刚刚完成GraduatUniversit,GraduatUniversit,NetworkDesignandysis-----Wang

GraduatUniversit,GraduatUniversit,pdfAi+1独立于i。所以离散时间随机过程Ni是NetworkDesign ysis-----Wang

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UsingthetheoremoftotalGraduatUniversit,NetworkDesignandGraduatUniversit,

定义：如果存在状态序列{P[Ni=n],n=0,1,2,·· i+ GraduatUniversit,NetworkDesignandGraduatUniversit,

GraduatUniversitGraduatUniversit,NetworkDesignandysis-----Wang

GraduatUniversitGraduatUniversit, NetworkDesignandysis-----Wang

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GraduatGraduatUniversit,NetworkDesignandysis-----Wang

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常⽤分布 GraduatGraduatUniversit, NetworkDesign ysis-----Wang

常⽤分布服务时间就是两个独立的指数随量的和。GraduatUniversit,由概率论知道，独立随量和的方差等于各自方差的和，随量和的期望等于各自期望的和（即使随量不是独GraduatUniversit, NetworkDesign ysis-----Wang

常⽤分布GraduatUniversit,GraduatUniversit,NetworkDesignandysis-----Wang

常⽤分布GraduatUniversit,GraduatUniversit, 都是有效的。⽤¥代换P-K 的服务时间分布方差，系统中的平均客户数可以看到是¥。NetworkDesign ysis-----Wang

常⽤分布GraduatGraduatUniversit,NetworkDesignandysis-----Wang

GraduatUniversitGraduatUniversit, ThestatediagramoftheimbeddedMarkovchain,Observationsaresoonafteradeparture.常⽤分布Grad