[ns] Problem in the wireless network

[Rohit Ramani <rohit@ee.iitb.ernet.in>]

I had tried to simulate a wireless network with two mobile nodes and tcp 
connection between them. Now I want to the sequence no. of packets in order, 
transmitted  by the tcp source at intervals of time. I have tried to do 
that but what it showing is some constant value, please explain what 
actually is happening?
 

this the tcl code which iam running
---------------------------------------------------------------------------
# ======================================================================
# Default Script Options
# ======================================================================
set opt(chan)		Channel/WirelessChannel
set opt(prop)		Propagation/TwoRayGround
set opt(netif)		Phy/WirelessPhy
set opt(mac)		Mac/802_11
set opt(ifq)		Queue/DropTail/PriQueue
set opt(ll)		LL
set opt(ant)            Antenna/OmniAntenna
set opt(ifqlen)		50		;# max packet in ifq
set opt(nn)		2		;# number of nodes
set opt(seed)		0.0		;# random no. generation
set opt(stop)		100.0		;# simulation time
set opt(tr)		out0.tr		;# trace file
set opt(cp)		""
set opt(sc)		""
set opt(rp)             dsr            ;# routing protocol script
set opt(lm)             "off"           ;# log movement

# ======================================================================

set AgentTrace			ON
set RouterTrace			ON
set MacTrace			OFF

#link layer values
#LL set mindelay_		50us
LL set delay_			25us
LL set bandwidth_		0	;# not used
LL set off_prune_		0	;# not used
LL set off_CtrMcast_		0	;# not used

# default declaration for src and destination ports
Agent/Null set sport_		0
Agent/Null set dport_		0

Agent/CBR set sport_		0
Agent/CBR set dport_		0

Agent/TCPSink set sport_	0
Agent/TCPSink set dport_	0

Agent/TCP set sport_		0
Agent/TCP set dport_		0
Agent/TCP set packetSize_	1460

Queue/DropTail/PriQueue set Prefer_Routing_Protocols    1

# unity gain, omni-directional antennas

# set up the antennas to be centered in the node and 1.5 meters above it
Antenna/OmniAntenna set X_ 0
Antenna/OmniAntenna set Y_ 0
Antenna/OmniAntenna set Z_ 1.5
Antenna/OmniAntenna set Gt_ 1.0
Antenna/OmniAntenna set Gr_ 1.0

# Initialize the SharedMedia interface with parameters to make
# it work like the 914MHz Lucent WaveLAN DSSS radio interface
Phy/WirelessPhy set CPThresh_ 10.0
Phy/WirelessPhy set CSThresh_ 1.559e-11
Phy/WirelessPhy set RXThresh_ 3.652e-10
Phy/WirelessPhy set Rb_ 2*1e6
Phy/WirelessPhy set Pt_ 0.2818
Phy/WirelessPhy set freq_ 914e+6 
Phy/WirelessPhy set L_ 1.0

# ======================================================================
proc log-movement {} {
    global logtimer ns_ ns

    set ns $ns_
    source ../mobility/timer.tcl
    Class LogTimer -superclass Timer
    LogTimer instproc timeout {} {
	global opt node_;
	for {set i 0} {$i < $opt(nn)} {incr i} {
	    $node_($i) log-movement
	}
	$self sched 0.1
    }

    set logtimer [new LogTimer]
    $logtimer sched 0.1
}

# ======================================================================
# Main Program
# ======================================================================
#
# Initialize Global Variables
#
set ns_		[new Simulator]
set chan	[new $opt(chan)]
set prop	[new $opt(prop)]
set topo	[new Topography]

#for cmu tracing
set tracefd	[open $opt(tr) w]

#for nam tracing 
set fa [open out1.tr w]
set nf 	[open wireless3-out.nam w]
$ns_ namtrace-all-wireless $nf 670 670

proc stop1 {} {
	global ns_ tracefd nf 
	$ns_ flush-trace
	close $tracefd
	close $nf
	close $fa
	exec xgraph out1.tr -geometry 800x400
}
 
$topo load_flatgrid 670 670
$prop topography $topo

#
# Create God
#
set god_ [create-god $opt(nn)]


#
# log the mobile nodes movements if desired
#
if { $opt(lm) == "on" } {
    log-movement
}

#
#  Create the specified number of nodes $opt(nn) and "attach" them
#  the channel.
#  Each routing protocol script is expected to have defined a proc
#  create-mobile-node that builds a mobile node and inserts it into the
#  array global $node_($i)
#

if { [string compare $opt(rp) "dsr"] == 0} { 
	for {set i 0} {$i < $opt(nn) } {incr i} {
		set node$i [dsr-create-mobile-node $i]
	}
} elseif { [string compare $opt(rp) "dsdv"] == 0} { 
	for {set i 0} {$i < $opt(nn) } {incr i} {
		set node$i [dsdv-create-mobile-node $i]
	}
}



#
# Source the Connection and Movement scripts
#
if { $opt(cp) == "" } {
	puts "*** NOTE: no connection pattern specified."
        set opt(cp) "none"
} else {
	puts "Loading connection pattern..."
	source $opt(cp)
}

if { $opt(sc) == "" } {
	puts "*** NOTE: no scenario file specified."
        set opt(sc) "none"
} else {
	puts "Loading scenario file..."
	source $opt(sc)
	puts "Load complete..."
}

#provide initial (X,Y, for now Z=0) coordinates
$node0 set X_ 5.0
$node0 set Y_ 2.0
$node0 set Z_ 0.0

$node1 set X_ 40.0
$node1 set Y_ 41.0
$node1 set Z_ 0.0




#set up traffic flow between nodes
set tcp [new Agent/TCP/Reno]
$tcp set window_ 25
$tcp set class_ 2
 set sink [new Agent/TCPSink]
$ns_ attach-agent $node0 $tcp
$ns_ attach-agent $node1 $sink
$ns_ connect $tcp $sink


proc record {} {
	global tcp fa
	set ns_ [Simulator instance]
	set time 1
	set noofbytes [$tcp set t_seqno_]
	set now [$ns_ now]
	puts $fa  "$now $noofbytes"
	$ns_ at [expr $now+$time] "record"
}


set ftp [new Application/FTP]
$ftp attach-agent $tcp
$ns_ at 0.0 "$ftp start"


#
# Tell all the nodes when the simulation ends
#
for {set i 0} {$i < $opt(nn) } {incr i} {
    $ns_ at $opt(stop).000000001 "$node_($i) reset";
}
$ns_ at $opt(stop).00000001 "puts \"NS EXITING...\" ; $ns_ halt"
$ns_ at $opt(stop) "stop1"


puts $tracefd "M 0.0 nn $opt(nn) x 670 y 670 rp $opt(rp)"
puts $tracefd "M 0.0 sc $opt(sc) cp $opt(cp) seed $opt(seed)"
puts $tracefd "M 0.0 prop $opt(prop) ant $opt(ant)"

$ns_ at 0.0 "record"
puts "Starting Simulation..."
$ns_ run