### Queuing Models in NS2

M/M/1 is a system with poisson arrival time,
servicing exponentially and a queue of unlimited capacity and type of FIFO
Queue. This is the simplest queuing system.
NS2 supports various distributions like pareto, exponential, constant,
unifrom, etc to handle the network dynamics and metrics. So it is very easy to test the given network
link to monitor a given queue using any of these queuing models. The listing 3 and 4 are monitoring the link when DropTail queue is used with a
capacity of finite and infinite. Listing 13.3 uses infinite capacity and
Listing 13.4 uses Finite capacity The output screen shot is shown below the
scripts for further understanding

Listing 3 – M/M/1 Queuing Model #new Simulator creation set ns [new Simulator] #trace file creation for capturing the UDP data set tf [open out.tr w] $ns trace-all $tf

#setting the exponential distribution param set lambda 30.0 set mu 33.0

#creation of nodes set n1 [$ns node] set n2 [$ns node] #The queue limit is 1Lakh as the capacity is infin…

Listing 3 – M/M/1 Queuing Model #new Simulator creation set ns [new Simulator] #trace file creation for capturing the UDP data set tf [open out.tr w] $ns trace-all $tf

#setting the exponential distribution param set lambda 30.0 set mu 33.0

#creation of nodes set n1 [$ns node] set n2 [$ns node] #The queue limit is 1Lakh as the capacity is infin…