This post is an extension to the broadcast example. In this, I am going to explain how a node can be entered into promiscuous mode so that it can overhear the packets sent, forward or received by neighboring nodes. It all require a class called
header file. Tap class offer a function called
To define the tap function, we need to inherit the class Tap. Usage of tap function and Tap class has shown with the broadcast example.
#===================================
# Simulation parameters setup
#===================================
set val(chan) Channel/WirelessChannel ;# channel type
set val(prop) Propagation/TwoRayGround ;# 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) 5 ;# number of mobilenodes
set val(rp) SB ;# routing protocol
set val(ie) 100 ; # initial energy of a node
set val(em) EnergyModel ; # Energy model
set val(x) 100 ;# X dimension of topography
set val(y) 100 ;# Y dimension of topography
set val(stop) 50
Agent/SB set node_count $val(nn)
#===================================
# Attaching selected headers
#===================================
remove-all-packet-headers
add-packet-header Mac LL IP ARP LL SB
#===================================
# Initialization
#===================================
#Create a ns simulator
set ns [new Simulator]
#Setup topography object
set topo [new Topography]
$topo load_flatgrid $val(x) $val(y)
create-god $val(nn)
#Open the NS trace file
set tracefile [open bcast.tr w]
$ns trace-all $tracefile
#Open the NAM trace file
set namfile [open bcast.nam w]
$ns namtrace-all $namfile
$ns namtrace-all-wireless $namfile $val(x) $val(y)
set chan [new $val(chan)];#Create wireless channel
Mac/802_11 set dataRate 512Kbps
#===================================
# Node parameter setup
#===================================
$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 \
-topoInstance $topo \
-agentTrace ON \
-routerTrace ON \
-macTrace ON \
-movementTrace OFF \
-energyModel $val(em) \
-initialEnergy $val(ie) \
-rxPower 35.25e-23 \
-txPower 31.21e-23 \
-idlePower 712e-6 \
-sleepPower 144e-9
#===================================
# Nodes Definition
#===================================
for {set i 0} {$i < $val(nn)} {incr i} {
set node_($i) [$ns node]
$node_($i) color blue
}
for {set i 0} {$i < $val(nn)} {incr i} {
set u_($i) [new Agent/SB]
$ns attach-agent $node_($i) $u_($i)
}
$node_(0) set X_ 0.0
$node_(0) set Y_ 0.0
$node_(0) set Z_ 0
$node_(1) set X_ 40.0
$node_(1) set Y_ 0.0
$node_(1) set Z_ 0
$node_(2) set X_ 25.0
$node_(2) set Y_ 0.0
$node_(2) set Z_ 0
$node_(3) set X_ 0.0
$node_(3) set Y_ 75.0
$node_(3) set Z_ 0
$node_(4) set X_ 60.0
$node_(4) set Y_ 20.0
$node_(4) set Z_ 0
#$ns at 1.0 "$node_(0) setdest 99.0 99.0 15.0"
for {set i 0} {$i < $val(nn)} {incr i} {
$ns at 0.0 "[$node_($i) set ragent_] base-station"
}
for {set i 0} {$i < $val(nn)} {incr i} {
$ns initial_node_pos $node_($i) 10
}
for {set i 0} {$i < $val(nn)} {incr i} {
[$node_($i) set ragent_] install-tap [$node_($i) set mac_(0)]
}
proc finish {} {
global ns tracefile namfile
$ns flush-trace
close $tracefile
close $namfile
Agent/SB print-stats
exec nam bcast.nam &
exit 0
}
#===================================
# Reset the nodes
#===================================
for {set i 0} {$i < $val(nn) } { incr i } {
$ns at $val(stop) "$node_($i) reset"
}
#===================================
# Simulation start up
#===================================
$ns at $val(stop) "$ns nam-end-wireless $val(stop)"
$ns at $val(stop) "finish"
$ns at $val(stop) "puts \"done\" ; $ns halt"
puts "before sim run"
$ns run
