Hi Marco,
Thanks for your reply and suggestions. I have tried what you have
suggested but the problem still remains as I don't get any throughput
still.
I have a feeling that I am not doing it right. I have added the script
to attach one traffic source and one traffic sink to each node but it is
not helping. I will be grateful if you can check the way I am trying to
do this in the script below.
I am using the old trace. If I reduce it to two nodes I can see the RTS
and CTS being send even without setting the RTSthreshold to 0. I have
set the values of CWmin to 31 and Cwmax to 255 and want to get the
saturation throughput when all nodes are contending.
For saturation I am generating the packets at 0.005 sec and also set the
CBR rate to 1Mbps as suggested by you.
I have doubt at places:
1. The way I generate the topology using random number generator and
making connections i.e. attaching udp and sink to each of the nodes is
wrong. I have seen people using cbrgen.tcl for this but I am not
familiar with tha. I want to generate this for 10, 20 ,30 40 and 50
nodes so because of this scaling I cannot do the connections for all
individually. If you can tell me some other way to generate the topology
for higher no. of nodes and making connections?
2. The other issue is that I am using a packet size of 1024 bytes but
the trace file shows it broken into two i.e. one packet 1000 and the
other 24 and that is because of fragmentation I tried to set the udp
packet size to 2000 but I am not sure if this is the right way to
counter this as it is not working. How to fix this?
3. This same script works if I use any routing protocol instead of
DumbAgent ? but I want to make it work with DumbAgent first and then see
what routing can bring up
4. I cannot see any data being transmitted in the trace file? where as
all other events are taking place i.e. at RTR and AGT level and even MAC
but it either collides or is dropped at the queue.
Looking forward for your help. Thanking you in advance.
Best Regards,
Riz
# Script to reproduce the results of Bianchi's paper
# ======================================================================
# Define options
# ======================================================================
set val(chan) Channel/WirelessChannel ;# channel type
set val(prop) Propagation/FreeSpace ;# radio-propagationmodel
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)
# set up topography object
set topo [new Topography]
$topo load_flatgrid $val(x) $val(y)
#
# Create God
#
set god_ [ create-god $val(nn) ]
$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_ 0
set chan_1_ [new $val(chan)]
$chan_1_ set delay_ 1us
set rng [new RNG]
$rng seed 0
set rand1 [new RandomVariable/Uniform]
$rand1 use-rng $rng
$rand1 set min_ -50.0
$rand1 set max_ 50.0
#
# Create the specified number of mobilenodes [$val(nn)] and "attach"
them
# to the channel.
# 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 250+[$rand1 value]]
set y [expr 150+[$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 udp([expr $i +1]) [new Agent/UDP]
Agent/UDP set packetSize_ 2000
$ns_ attach-agent $node_([expr $i +1]) $udp([expr $i +1])
set sink($i) [new Agent/Null]
$ns_ attach-agent $node_([expr $i +1]) $sink($i)
$ns_ connect $udp($i) $sink($i)
set sink([expr $i +1]) [new Agent/Null]
$ns_ attach-agent $node_($i) $sink([expr $i +1])
$ns_ connect $udp([expr $i +1]) $sink([expr $i +1])
set cbr($i) [new Application/Traffic/CBR]
$cbr($i) set packetSize_ 1024
$cbr($i) set interval_ 0.005 # 0.01
$cbr($i) set rate_ 1e6
$cbr($i) attach-agent $udp($i)
set cbr([expr $i +1]) [new Application/Traffic/CBR]
$cbr([expr $i +1]) set packetSize_ 500
$cbr([expr $i +1]) set interval_ 0.005 # 0.01
$cbr([expr $i +1]) set rate_ 1e6
$cbr([expr $i +1]) attach-agent $udp([expr $i +1])
$ns_ at 0.0 "$cbr($i) start"
$ns_ at $val(simtime) "$cbr($i) stop"
$ns_ at 0.0 "$cbr([expr $i +1]) start"
$ns_ at $val(simtime) "$cbr([expr $i +1]) stop"
}
# define different colors for nam data flows
$ns_ color 0 Green
$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
_----------------------------------------------
-----Original Message-----
From: Marco Fiore [mailto:[EMAIL PROTECTED]
Sent: Friday, 13 April 2007 2:26 AM
To: [EMAIL PROTECTED]; isi
Subject: R: [ns] Help in simulating Bianchi's results
Hi Riz,
>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
attach one traffic source and one traffic sink to each node.
>2. whether cbr interval 0.005 can meet the saturation requirement
you
are in saturation conditions when each node generates
more traffic than
it can send. Broadly, it depends on the bandwidth
you are using and one
the number of contending nodes, but you
can choose a very high value,
so that even a single source would
saturate the channel (e.g. if you
are using 11Mbps as MAC datarate,
you can set the CBR rate to 11Mbps,
and you're sure your nodes
are backlogged).
>3. I cannot see any RTS
and CTS in the trace file why?
because they are off. RTSthreshold_
controls the RTS/CTS
(frames smaller than this value go without
RTS/CTS, frames
bigger require RTS/CTS, defualt is 3000 - i.e. never
use it),
so the try adding the line
$val(mac) set RTSthreshold_ 0
bye,
Marco
