ns模拟1

cmdblock

set ns [new Simulator]
#define different colors for data flows(for nam)
ns color 1 Blue
ns color 2 Red
#open the trace file
set tracefile1 [open out.tr w]
set winfile [open WiinFile w]
$ns trace-all $tracefile1
#open the nam trace file
set namfile [open out.nam w]
$ns namtrace-all $namfile
#define a 'finish' procedure
proc finish {} {
    global ns tracefile1 namfile
    $ns flush-trace
    close $tracefile1
    close $namfile
    exec nam out.nam &
    exit 0
}
#create six nodes
set n0 [$ns node]
set n1 [$ns node]
set n2 [$ns node]
set n3 [$ns node]
set n4 [$ns node]
set n5 [$ns node]
#create links between the nodes
$ns duplex-link $n0 $n2 2Mb 10ms DropTail
$ns duplex-link $n1 $n2 2Mb 10ms DropTail
$ns simplex-link $n2 $n3 0.3Mb 100ms DropTail
$ns simplex-link $n3 $n2 0.3Mb 100ms DropTail
$ns duplex-link $n3 $n4 0.5Mb 40ms DropTail
$ns duplex-link $n3 $n5 0.5Mb 30ms DropTail
#give node position(for nam)
$ns duplex-link-op $n0 $n2 orient right-down
$ns duplex-link-op $n1 $n2 orient right-up
$ns simplex-link-op $n2 $n3 orient right
$ns simplex-link-op $n3 $n2 orient left
$ns duplex-link-op $n3 $n4 orient right-up
$ns duplex-link-op $n3 $n5 orient right-down
#set queue size of link (n2-n3) to 20
$ns queue-limit $n2 $n3 20
#setuup a tcp connection
set tcp [new Agent/TCP]
$ns attach-agent $n0 $tcp
set sink [new Agent/TCPSink]
$ns attach-agent $n4 $sink
$ns connect $tcp $sink
$tcp set fid_ 1
$tcp set packetsize_ 552
#setup a ftp over tcp connection
set ftp [new Application/FTP]
$ftp attach-agent $tcp
#setup a udp connection
set udp [new Agent/UDP]
$ns attach-agent $n1 $udp
set null [new Agent/Null]
$ns attach-agent $n5 $null
$ns connect $udp $null
$udp set fid_ 2
#setup a cbr or udp connection
set cbr [new Application/Traffic/CBR]
$cbr attach-agent $udp
$cbr set packetsize_ 1000
$cbr set rate_ 0.01Mb
$cbr set random_ false
$ns at 0.1 "$cbr start"
$ns at 1.0 "$ftp start"
$ns at 124.0 "$ftp stop"
$ns at 124.5 "$cbr stop"
#procedure for plotting window size
proc plotwindow {tcpsource file} {
global ns
set time 0.1
set now [$ns now]
set cwnd [$tcpsource set cwnd_]
puts $file "$now $cwnd"
$ns at [expr $now+$time] "plotwindow $tcpsource $file"
}
$ns at 0.1 "plotwindow $tcp $winfile"
$ns at 125.0 "finish"
$ns run
               
               
               

本文来自ChinaUnix博客，如果查看原文请点：http://blog.chinaunix.net/u3/93856/showart_2014614.html