About little's law The result is very useful because of its generality System should be stationary without any other assumptions 150 Arrival process can be anything Treat system as a black box 之100 Can be applied to whole system or Any part of the system It can naturally explain why stationary On rainy days. traffic moves slower 10.0 and the streets are more crowded t(×103s) a fast-food restaurant needs a smaller waiting roomCommunication Networks About Little’s Law • The result is very useful because of its generality – System should be stationary – Without any other assumptions • Arrival process can be anything • Treat system as a black box • Can be applied to whole system • or Any part of the system • It can naturally explain why – On rainy days, traffic moves slower and the streets are more crowded – A fast-food restaurant needs a smaller waiting room 7 0.0 2.0 4.0 6.0 8.0 10.0 0 50 100 150 200 N t (103 s) =1.1 =0.9 stationary