Re: [ns] weird throughput result

[Devendra Goyal <goyald@email.uc.edu>]

#received packets * packetsize(bytes) * 8 (bits per byte) / total time.
It seems, if I divide both by 2, I would be getting correct values.
But I do not see where to get this 2 from.

On Mon, 22 Jan 2001, Jacky Lee wrote:

> How did you get your throughput?
> --- Devendra Goyal <goyald@email.uc.edu> wrote:
> > I ran one experiment, created a link between two
> > nodes with following
> > specf.
> > $ns duplex-link $n1 $n2 10Mb 1ms DropTail
> >
> > and a cbr with following specf.
> > $cbr0 set packetSize_ 1500
> > $cbr0 set rate_ 15Mb
> >
> > on running this, I get following output:
> > For Packetsize= 1500 and Interval= 1.0 :
> >         Application Load     	= 29.739659045857014
> > Mbs (enqueued packet)
> >         Throughput              = 15.12356283864147
> > Mbs
> >         Avg. Plus Delay         =
> > 0.03948850052429101 sec
> >         Avg. Minus Delay        =
> > 0.001793289059769138 sec
> >         Packet Drop Prob        = 0.4914681834340562
> >
> >
> > The Throughput is more than the link bandwidth.
> > I cannot explain this. Any idea...
> > Thanks a lot
> > DEV
> >
> > The program is appended:
> >
> >
> > #Create a simulator object
> > set ns [new Simulator]
> >
> > #Open the trace file
> > set nf [open out.ex2 w]
> > $ns trace-all $nf
> >
> > #Define a 'finish' procedure
> > proc finish {} {
> >         global ns nf
> >         $ns flush-trace
> >         #Close the trace file
> >         close $nf
> >         exit 0
> > }
> >
> > #Create four nodes
> > set n1 [$ns node]
> > set n2 [$ns node]
> >
> > #Create links between the nodes
> > $ns duplex-link $n1 $n2 10Mb 1ms DropTail
> >
> > #Create a UDP agent and attach it to node n0
> > set udp0 [new Agent/UDP]
> > $udp0 set class_ 1
> > $ns attach-agent $n1 $udp0
> >
> > # Create a CBR traffic source and attach it to udp0
> > set cbr0 [new Application/Traffic/CBR]
> > $cbr0 set packetSize_ 1500
> > $cbr0 set rate_ 15Mb
> > $cbr0 attach-agent $udp0
> >
> > #Create a Null agent (a traffic sink) and attach it
> > to node n3
> > set null0 [new Agent/Null]
> > $ns attach-agent $n2 $null0
> >
> > #Connect the traffic sources with the traffic sink
> > $ns connect $udp0 $null0
> >
> > #Schedule events for the CBR agents
> > $ns at 0 "$cbr0 start"
> > $ns at 4.5 "$cbr0 stop"
> > #Call the finish procedure after 5 seconds of
> > simulation time
> > $ns at 5.0 "finish"
> >
> > #Run the simulation
> > $ns run
> >
> >
>
>
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