# myfirst_ns.tcl
# create a simulator
set ns [new simulator]
create a trace file
set mytrace [open out.tr w]
$ns trace-all $mytrace
create a NAM trace file
set myNAM [open out.nam w]
$ns namtrace-all $myNAM
define a procedure finish
proc finish {} {
global ns mytrace myNAM
$ns flush-trace
close $mytrace
close $myNAM
exec nam out.nam &
exit 0
}
create nodes
set n0 [$ns node]
set n1 [$ns node]
set n2 [$ns node]
set n3 [$ns node]
set n4 [$ns node]
connect nodes with links
$ns duplex-link $n0 $n2 100Mb 5ms DropTail
$ns duplex-link $n1 $n2 100Mb 5ms DropTail
$ns duplex-link $n2 $n4 54Mb 10ms DropTail
$ns duplex-link $n2 $n3 54Mb 10ms DropTail
$ns duplex-link $n3 $n4 10Mb 15ms DropTail
$ns queue-limit $n2 n3 40
create a UDP agent
set udp [new Agent/UDP]
$ns attach-agent $n0 $udp
set null [new Agent/Null]
$ns attach-agent $n3 $null
$ns connect $udp $null
$udp set fid_1
create a CBR traffic source
set cbr [new Application/Traffic/CBR]
$cbr attach-agent $udp
$cbr set packetSize_1000
$cbr set rate_2Mb
create a TCP agent
set tcp [new Agent/TCP]
$ns attach-agent $n1 $tcp
set sink [new Agent/TCPSink]
$ns attach-agent $n4 $sink
$ns connect $tcp $sink
$tcp set fid_2
create an FTP session
set ftp [new Application/FTP]
$ftp attach-agent $tcp
schedule events
ns at 0.05 "$ftp start"
ns at 0.1 "$cbr start"
ns at 60.0 "$ftp stop"
ns at 60.5 "$cbr stop"
ns at 61 "finish"
}
# Start the simulation
$ns run
ON THE CYGWIN I RUN THE FILE
$ ns myfirst_ns.tcl
IT'S ERROR SHOW BELOW
$ myfirst_ns.tcl
invalid command
name "simulator"
while executing
"simulator
create _o3"
invoked from
within
"catch"$className
create $o $args" msg"
invoked from
within
"if [catch
"$className create $o $args" msg] {
if [string match
"_FAILED _SHADOW_OBJECT_"$msg] {
delete $o
return""
}
global errorInfo
error "class
$.."
<procedure "new" line 3>
invoked from
within
"new
simulator"
invoked from
within
"set ns [new
simulator]"
<file
"myfirst_ns.tcl" line3>
How to solve this?please help me out..i’m
very new
