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|
source timer.tcl
global ns
set ns [new Simulator]
$ns color 0 blue
$ns color 1 red
$ns color 2 darkgreen
set n0 [$ns node]
set n1 [$ns node]
set n2 [$ns node]
set n3 [$ns node]
puts n0=[$n0 id]
puts n1=[$n1 id]
puts n2=[$n2 id]
puts n3=[$n3 id]
set f [open out.tr w]
$ns trace-all $f
set nf [open out.nam w]
$ns namtrace-all $nf
#$ns duplex-link $n0 $n1 1.5Mb 10ms DropTail
$ns duplex-link $n0 $n2 10Mb 2ms DropTail
$ns duplex-link $n1 $n2 10Mb 2ms DropTail
$ns duplex-link $n2 $n3 1.5Mb 10ms DropTail
$ns duplex-link-op $n0 $n2 orient right-up
$ns duplex-link-op $n1 $n2 orient right-down
$ns duplex-link-op $n2 $n3 orient right
$ns duplex-link-op $n2 $n3 queuePos 0.5
$ns queue-limit $n2 $n3 8
Class Sender -superclass {Agent/Message Timer}
Class Receiver -superclass Agent/Message
Sender instproc init {} {
$self next
$self reset
$self set window_ 4
}
Sender instproc reset {} {
$self instvar seqno_ ack_
set seqno_ 0
set ack_ 0
}
Sender instproc start {} {
$self transmit
}
Sender instproc reset_timer {} {
$self cancel
$self sched 0.05
}
Sender instproc timeout {} {
$self instvar seqno_ ack_
set seqno_ $ack_
$self transmit
}
Sender instproc cansend {} {
$self instvar seqno_ window_ ack_
return [expr $seqno_ < $ack_ + $window_]
}
Sender instproc sendnext {} {
$self instvar seqno_
$self send $seqno_
incr seqno_
$self reset_timer
}
Sender instproc transmit {} {
while [$self cansend] {
$self sendnext
}
}
Sender instproc recv msg {
$self instvar ack_
set ack_ $msg
$self transmit
}
Sender set packetSize_ 400
Receiver set packetSize_ 40
Receiver instproc init {} {
$self next
$self reset
}
Receiver instproc reset {} {
$self instvar ack_
set ack_ 0
}
Receiver instproc recv msg {
set seqno $msg
$self instvar ack_
if { $seqno == $ack_ } {
incr ack_
}
$self send $ack_
}
set sndr [new Sender]
$ns attach-agent $n0 $sndr
$sndr set fid_ 0
set rcvr [new Receiver]
$ns attach-agent $n3 $rcvr
$rcvr set fid_ 1
$ns connect $sndr $rcvr
$sndr set window_ 1
# start up - stop-and-wait
$ns at 0.0 "$sndr start"
# do pipelining
$ns at 0.2 "$sndr set window_ 6"
# cause queue overflow
$ns at 0.4 "$sndr reset; $rcvr reset; $sndr set window_ 10"
$ns at 0.6 "$ns queue-limit $n2 $n3 20"
$ns at 0.8 "$sndr set window_ 14"
$ns at 1.0 "finish"
proc finish {} {
global nf
close $nf
puts "running nam..."
exec nam out.nam &
exit 0
}
$ns run
|
