############################################################## Dawn Choe 		Caltech 12-18-2003# Bartek Wydrowski 	Caltech 03-18-2004#  ############################################################# ---------- HELPER FUNCTIONS ------------# Create a FAST Tcp connectionproc create_tcp_fast { idx src dst start stop } {	global tcps	global ftps	global ns	global sinks	global tcps_start	global tcps_stop	puts "New TCP connection";	# set source agent and application	set tcps($idx) [new Agent/TCP/Fast]	$tcps($idx) set class_ 2 	$tcps($idx) set window_ 100000	$tcps($idx) set alpha_ 100	$tcps($idx) set beta_ 100	$tcps($idx) set mi_threshold_ 0.006	$ns attach-agent $src $tcps($idx)	set ftps($idx) [new Application/FTP]	$ftps($idx) attach-agent $tcps($idx)	# set sink 	set sinks($idx) [new Agent/TCPSink/Sack1]	$ns attach-agent $dst $sinks($idx)	$ns connect $tcps($idx) $sinks($idx)	set tcps_start($idx) [expr $start]	set tcps_stop($idx)  [expr $stop]	$ns at $start "$ftps($idx) start"	$ns at $stop  "$ftps($idx) stop"}# Record Procedureset have_reset_mi_threshold 0proc record {} {	global tcps ntcps	global f0    	global queueMoniF queueMoniB	global tcps_start tcps_stop	global have_reset_mi_threshold SimDuration	#get an instance of the simulator	set ns [Simulator instance]	#set the time afterwhich the procedure should be called again	set time 0.005	set now [$ns now]	set queueF [$queueMoniF set pkts_]	set queueB [$queueMoniB set pkts_]		set rate 0	for {set i 0} {$i < $ntcps} {incr i} {		if { ($now > $tcps_start($i)) && ($now < $tcps_stop($i)) } {			set window      [expr [$tcps($i) set cwnd_]];			set rtt 	[expr [$tcps($i) set avgRTT_]];			set bRTT	[expr [$tcps($i) set baseRTT_]];			set old_window 	[expr [$tcps($i) set avg_cwnd_last_RTT_]];			set total_pkt_num	[expr [$tcps($i) set t_seqno_]]			if { $rtt > 0 }  {		        	set rate	[expr $window/$rtt]			}			if { $bRTT < 9999999 } {		  		puts $f0 "$i $now $queueF $queueB $rate $window $rtt $bRTT $old_window $total_pkt_num"  			}		}		if { ($now > [expr $SimDuration/2]) && ($have_reset_mi_threshold < 1) } {			$tcps($i) set mi_threshold_ 0.001			set have_reset_mi_threshold 1		}	}        	# Re-schedule the procedure	$ns at [expr $now+$time] "record"}# Define 'finish' procedure (include post-simulation processes)proc finish {} {	global ns	global f0	global f_all	$ns flush-trace	close $f_all		close $f0	puts "Finished."	exit 0}# ------ SIMULATION SPECIFIC SCRIPT -----------# The preambleset ns [new Simulator]$ns use-scheduler Heap# Predefine tracingset Name "fast-test6-record.dat";set Q1 "fast-test6-queue1.dat";set Q2 "fast-test6-queue2.dat";set f0 [open $Name w]set f1 [open $Q1 w]set f2 [open $Q2 w]set f_all [open nstrace.dat w]#$ns trace-all $f_all# Define the topologyset Cap 100set Del 50set r1 [$ns node]set r2 [$ns node]set r3 [$ns node]$ns duplex-link $r1 $r2  [expr $Cap]Mbps [expr $Del]ms DropTailset botqF [[$ns link $r1 $r2] queue]set botqB [[$ns link $r2 $r1] queue]	$ns queue-limit $r1 $r2 2000000; $ns queue-limit $r2 $r1 2000000; # Create Sources and Start & Stop timesset ntcps    1;set SimDuration 20;create_tcp_fast 0 $r1 $r2 0  20#$ns create-connection TCP $r1 TCPSink $r2 1set starttime 0.0set finishtime $SimDuration# Monitor the queue between source switch and destination switchset queueMoniF [$ns monitor-queue $r1 $r2 $f1 0.1]set queueMoniB [$ns monitor-queue $r2 $r1 $f2 0.1]# Run the Simulation$ns at 0.0 "record"$ns at $SimDuration "finish"puts "Simulating $SimDuration Secs."$ns run