Hello Qadous,
I have used the tcl script below to test the error modeling. I am using
ns-2.29 and when I increase the value of rate_ from 0 to 0.05 I get more
duplicated packets, and collisions, which is a result of transmission
errors.
>I used the following command to specify the Error model for mobile node.
>
>$ns_ node-config ErrProc -Incoming ErrProc "Uniform"
>by the way, there is no errors of running the file after these changes.
>thank you in advance for clarification.
>
>
I think that the right way is this one:
$ns_ node-config ErrProc -IncomingErrProc UniformErr
Here is an example tcl script:
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# Open result files for writing
set tracefd [open ex_2node.tr w]
set namtrace [open ex_2node.nam w]
# Create new simulator instance
set ns_ [new Simulator]
$ns_ trace-all $tracefd
$ns_ namtrace-all-wireless $namtrace 1000 1000
# Set up topography object using a flat grid of 1000x1000m
set topo [new Topography]
$topo load_flatgrid 1000 1000
proc UniformErr {} {
set err [new ErrorModel]
$err unit packet
$err set rate_ 0.05
$err ranvar [new RandomVariable/Uniform]
$err drop-target [new Agent/Null]
return $err
}
# Configure nodes
create-god 2
$ns_ node-config -adhocRouting AODV -topoInstance $topo -channel [new
Channel/WirelessChannel] \
-llType LL -macType Mac/802_11 -ifqType Queue/DropTail/PriQueue
-ifqLen 50 \
-antType Antenna/OmniAntenna -propType Propagation/TwoRayGround
-phyType Phy/WirelessPhy \
-agentTrace ON -routerTrace ON -macTrace ON -movementTrace OFF \
-IncomingErrProc UniformErr
# create 2 nodes
proc setup_node {id x y z} {
global ns_ node_
set node_($id) [$ns_ node]
$node_($id) set X_ $x
$node_($id) set Y_ $y
$node_($id) set Z_ $z
$node_($id) random-motion 0
$ns_ initial_node_pos $node_($id) 20
}
setup_node 1 100 200 0
setup_node 2 300 200 0
# start nodes
for {set i 1} {$i < 3} {incr i} {$ns_ at 0 "$node_($i) start";}
# setup UDP traffic node 1 -> 2 using constant bitrate source
set udp(1) [new Agent/UDP]
set sink(1) [new Agent/Null]
set cbr(1) [new Application/Traffic/CBR]
$cbr(1) set class_ 1
$cbr(1) set fid_ 1
$cbr(1) set packetSize_ 500
$cbr(1) set interval_ 0.05
$cbr(1) attach-agent $udp(1)
$ns_ attach-agent $node_(1) $udp(1)
$ns_ attach-agent $node_(2) $sink(1)
$ns_ connect $udp(1) $sink(1)
$ns_ at 1 "$cbr(1) start"
# set stop time, start simulation
for {set i 1} {$i < 3} {incr i} {$ns_ at 1.0 "$node_($i) reset";}
$ns_ at 50.10 "stop"
$ns_ at 50.101 "puts \"NS EXITING...\" ; $ns_ halt"
proc stop {} {
global ns_ tracefd
$ns_ flush-trace
close $tracefd
}
# run simulation
$ns_ run
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Best regards,
Svilen
--
+------------------------------------------+
| M.Sc. Svilen Ivanov |
| Institute for Distributed Systems (IVS) |
| Otto-von-Guericke University - Magdeburg |
| http://ivs.cs.uni-magdeburg.de/~svilen/ |
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