Hi,
I am new to Ns and am trying to simulate the results for the paper:
G. Bianchi, "Performance Analysis of the IEEE 802.11 Distributed
Coordination Function,"IEEE JSAC, vol. 18, no. 3, March 2000
My script is given below when I am running it with DumbAgent as the
routing protocol I don't see any activity in the trace file and the
throughput is zero but with a routing protocol I can get some throughput
and I understand why this is happening but I don't get why my script
with dumbagent is not working. I am using the parameters from Bainchi's
paper
I have a few questions:
1. I am not sure about how to generate a scenario where all the
nodes are contending as in my case of 10 nodes only 0 2 4 6 8 are
contending and the other 1 3 5 7 9 are the sink or them so how can I
come with a scenario where all nodes are coteding as in Bianchi's paper
2. whether cbr interval 0.005 can meet the saturation requirement
3. I cannot see any RTS and CTS in the trace file why?
# Script to reproduce the results of Bianchi's paper
# ======================================================================
# Define options
# ======================================================================
set val(chan) Channel/WirelessChannel ;# channel type
set val(prop) Propagation/FreeSpace ;# radio-propagation
model
set val(netif) Phy/WirelessPhy ;# network
interface type
set val(mac) Mac/802_11 ;# MAC type
set val(ifq) Queue/DropTail/PriQueue ;# interface queue
type
set val(ll) LL ;# link layer type
set val(ant) Antenna/OmniAntenna ;# antenna model
set val(ifqlen) 50 ;# max packet in ifq
set val(nn) 10 ;# default number
of mobilenodes
set val(rp) DumbAgent ;# routing protocol
DumbAgent
set val(x) 100.0 ;
set val(y) 100.0 ;
set val(simtime) 30.0 ; #sim time 600
# ======================================================================
# Main Program
# ======================================================================
set ns_ [new Simulator]
set tracefd [open bianchi.tr w]
$ns_ trace-all $tracefd
set namtrace [open bianchi.nam w] ;# for nam tracing
$ns_ namtrace-all-wireless $namtrace $val(x) $val(y)
#$ns_ use-newtrace
#
# set up topography object
#
set topo [new Topography]
$topo load_flatgrid $val(x) $val(y)
#
# Create God
#
set god_ [ create-god $val(nn) ]
# Parameters for 802.11
$val(mac) set SlotTime_ 0.000050
$val(mac) set SIFS_ 0.000028
$val(mac) set PreambleLength_ 0
$val(mac) set PLCPHeaderLength_ 128
$val(mac) set PLCPDataRate_ 1.0e6
$val(mac) set DIFS_ 0.000128
$val(mac) set dataRate_ 1.0e6
$val(mac) set basicRate_ 1.0e6
$val(mac) set CWMin_ 31
$val(mac) set CWMax_ 255
#$val(mac) set RTShreshold_ 3000
set chan_1_ [new $val(chan)]
set rng [new RNG]
$rng seed 1
set rand1 [new RandomVariable/Uniform]
$rand1 use-rng $rng
$rand1 set min_ -50.0
$rand1 set max_ 50.0
#
# Create the specified number of nodes
# configure node
$ns_ node-config -adhocRouting $val(rp) \
-llType $val(ll) \
-macType $val(mac) \
-ifqType $val(ifq) \
-ifqLen $val(ifqlen) \
-antType $val(ant) \
-propType $val(prop) \
-phyType $val(netif) \
-channel $chan_1_ \
-topoInstance $topo \
-agentTrace ON \
-routerTrace ON \
-macTrace ON \
-movementTrace OFF
for {set i 0} {$i < $val(nn) } {incr i} {
set node_($i) [$ns_ node]
$node_($i) random-motion 0 ;#
disable random motion
set x [expr 50+[$rand1 value]]
set y [expr 50+[$rand1 value]]
$node_($i) set X_ $x
$node_($i) set Y_ $y
$node_($i) set Z_ 0.0
$ns_ initial_node_pos $node_($i) 20
}
#=================================================
# Agents
#=================================================
for {set i 0} {$i < $val(nn)} {incr i 2} {
set udp($i) [new Agent/UDP]
Agent/UDP set packetSize_ 2000
$ns_ attach-agent $node_($i) $udp($i)
set sink($i) [new Agent/Null]
$ns_ attach-agent $node_([expr $i +1]) $sink($i)
#$ns_ attach-agent $node_($i) $sink($i)
$ns_ connect $udp($i) $sink($i)
set cbr($i) [new Application/Traffic/CBR]
$cbr($i) set packetSize_ 1024
$cbr($i) set interval_ 0.005
$cbr($i) attach-agent $udp($i)
$ns_ at 0.0 "$cbr($i) start"
$ns_ at $val(simtime) "$cbr($i) stop"
}
$ns_ at $val(simtime).1 "stop"
$ns_ at $val(simtime).2 "puts \"NS EXITING...\" ; $ns_ halt"
proc stop {} {
global ns_ tracefd
$ns_ flush-trace
close $tracefd
puts "Finishing ns.."
}
puts "Starting Simulation..."
$ns_ run
The awk script I am using is :
#------------------------------------------------------------------
#the awk script is simply: for throughput
#-------------------------------------------------------------------
BEGIN {num_cbr_recv=0; num_cbr_sent=0; sim_time=30; data_rate=1e6;
num_rts_sent=0; num_cts_sent=0; num_col=0} {
action=$1;
hashar=$5
type=$7;
type2=$4
if (action == "r" && type == "cbr" && type2 == "MAC") {
num_cbr_recv++;
};
}
END{
throughput= ((num_cbr_recv*1024*8)/data_rate)/sim_time;
print("throughput=", throughput);
}
Thanking you in advance.
Riz
