[ns] problem of Error model in wireless simulation...

John Jeon John Jeon" <skchun98@hanmail.net
Thu Apr 25 05:18:44 2002 

 Hello! all
<br> I'm using ErroModel in my simulation. I want to create a wireless link which has a variable BER(bit error rate).and I only have used two static node in wireless network environment. 
<br>I refer to http://mailman.isi.edu/pipermail/ns-users/2002-April/022080.html that error model.and add that error model in tcl/ex/simple-wireless.tcl.but I can't find any packet drop-"D" and any change with different BER values in the trace file.
<br>I guess the errProc option has no effect.
<br>Does anyone know why and how to resolve it?...
<br>and furthermore how can make effective error model in wireless environment?
<br>Best regards!Thanks.
<br>                                 -John jeon                                        
<br> 
<br>the tcl script I used is as following:
<br>
<br># ======================================================================
<br># Define options
<br># ======================================================================
<br>set val(chan)           Channel/WirelessChannel    ;# channel type
<br>set val(prop)           Propagation/TwoRayGround   ;# radio-propagation model
<br>set val(netif)          Phy/WirelessPhy            ;# network interface type
<br>set val(mac)            Mac/802_11                 ;# MAC type
<br>set val(ifq)            Queue/DropTail/PriQueue    ;# interface queue type
<br>set val(ll)             LL                         ;# link layer type
<br>set val(ant)            Antenna/OmniAntenna        ;# antenna model
<br>set val(ifqlen)         50                         ;# max packet in ifq
<br>set val(nn)             2                          ;# number of mobilenodes
<br>set val(rp)             DSDV                       ;# routing protocol
<br>set val(err) 		UniformErrorProc           ;# Define Error model  
<br># ======================================================================
<br># Main Program
<br># ======================================================================
<br>
<br>#
<br># Initialize Global Variables
<br>#
<br>set ns_		[new Simulator]
<br>set tracefd     [open simple2.tr w]
<br>$ns_ trace-all $tracefd
<br>
<br># set up topography object
<br>set topo       [new Topography]
<br>
<br>$topo load_flatgrid 500 500
<br>
<br># Add Error model
<br>
<br>ErrorModule set debug_ false
<br>ErrorModel set enable_ 1
<br>ErrorModel set markecn_ false
<br>ErrorModel set bandwidth_ 2Mb
<br>
<br>proc UniformErrorProc {} {
<br>	global opt
<br>	set errObj [new ErrorModel]
<br>	$errObj set rate_ 0.5 
<br>	$errObj unit byte
<br>	return $errObj
<br>}
<br>
<br>#
<br># Create God
<br>#
<br>create-god $val(nn)
<br>
<br>#
<br>#  Create the specified number of mobilenodes [$val(nn)] and "attach" them
<br>#  to the channel. 
<br>#  Here two nodes are created : node(0) and node(1)
<br>
<br># configure node
<br>
<br>        $ns_ node-config -adhocRouting $val(rp) \
<br>			 -llType $val(ll) \
<br>			 -macType $val(mac) \
<br>			 -ifqType $val(ifq) \
<br>			 -ifqLen $val(ifqlen) \
<br>			 -antType $val(ant) \
<br>			 -propType $val(prop) \
<br>			 -phyType $val(netif) \
<br>			 -channelType $val(chan) \
<br>			 -topoInstance $topo \
<br>			 -agentTrace ON \
<br>			 -routerTrace ON \
<br>			 -macTrace OFF \
<br>			 -movementTrace OFF			
<br>			 
<br>	for {set i 0} {$i < $val(nn) } {incr i} {
<br>		set node_($i) [$ns_ node]	
<br>		$node_($i) random-motion 0		;# disable random motion
<br>	}
<br>
<br>#
<br># Provide initial (X,Y, for now Z=0) co-ordinates for mobilenodes
<br>#
<br>$node_(0) set X_ 5.0
<br>$node_(0) set Y_ 2.0
<br>$node_(0) set Z_ 0.0
<br>
<br>$node_(1) set X_ 390.0
<br>$node_(1) set Y_ 385.0
<br>$node_(1) set Z_ 0.0
<br>
<br>#
<br># Now produce some simple node movements
<br># Node_(1) starts to move towards node_(0)
<br>#
<br>$ns_ at 10.0 "$node_(1) setdest 25.0 20.0 15.0"
<br>$ns_ at 10.0 "$node_(0) setdest 20.0 18.0 1.0"
<br>
<br># Node_(1) then starts to move away from node_(0)
<br>#$ns_ at 100.0 "$node_(1) setdest 490.0 480.0 15.0" 
<br>
<br># Setup traffic flow between nodes
<br># TCP connections between node_(0) and node_(1)
<br>
<br>set tcp [new Agent/TCP]
<br>$tcp set class_ 2
<br>set sink [new Agent/TCPSink]
<br>$ns_ attach-agent $node_(0) $tcp
<br>$ns_ attach-agent $node_(1) $sink
<br>$ns_ connect $tcp $sink
<br>
<br>
<br>set ftp [new Application/FTP]
<br>$ftp attach-agent $tcp
<br>$ns_ at 10.0 "$ftp start" 
<br>
<br>#
<br># Tell nodes when the simulation ends
<br>#
<br>for {set i 0} {$i < $val(nn) } {incr i} {
<br>    $ns_ at 150.0 "$node_($i) reset";
<br>}
<br>$ns_ at 150.0 "stop"
<br>$ns_ at 150.01 "puts \"NS EXITING...\" ; $ns_ halt"
<br>proc stop {} {
<br>    global ns_ tracefd
<br>    $ns_ flush-trace
<br>    close $tracefd
<br>}
<br>
<br># execute Error model
<br>$ns_  node-config  -errProc $val(err)
<br> 
<br>
<br>puts "Starting Simulation..."
<br>$ns_ run
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>  
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