[ns] SEGMENTATION FAULT

[Nitin Nagar <nagar@cs.unr.edu>]

Hi
We have installed the ns-2 pakage today and when i tried to simulate a
topology file it gave the following script error:
 

gum:8 ns-allinone-2.1b6> nam template.tcl
Failed to start animator: 
class Animator: constructor failed: unmatched open brace in list
unmatched open brace in list
    while executing
"foreach item $traceevent {
if { $next == 1 } {
return $item
}
if { $item == $tag } {
set next 1
} 
}"
    (procedure "get_trace_item" line 3)
    invoked from within
"get_trace_item "-t" $line"
    (procedure "_o3" line 9)
    (Animator infer-network-model line 9)
    invoked from within
"$self infer-network-model $tracefile"
    (procedure "_o3" line 80)
    (Animator init line 80)
    invoked from within
"_o3 init template.tcl {}"
    (Class create line 1)
    invoked from within
"Animator create _o3 template.tcl {}"
    invoked from within
"catch "$className create $o $args" msg"
    (procedure "new" line 3)
    invoked from within
"new $ANIMATOR_CLASS_ $tracefile  [join $args]"


The topology file is:

#Create a simulator object
set ns [new Simulator]

$ns color 1 Blue
$ns color 2 Red


#Open the nam trace file
set nf [open out.nam w]
$ns namtrace-all $nf

#Define a 'finish' procedure
proc finish {} {
        global ns nf
        $ns flush-trace
        #Close the trace file
        close $nf
        #Execute nam on the trace file
        exec nam out.nam &
        exit 0
}


# Insert your own code for topology creation
# and agent definitions, etc. here

set n0 [$ns node]
set n1 [$ns node]
set n2 [$ns node]
set n3 [$ns node]

$ns duplex-link $n0 $n2 1Mb 10ms DropTail
$ns duplex-link $n1 $n2 1Mb 10ms DropTail
$ns duplex-link $n3 $n2 1Mb 10ms SFQ

#SQF = Stochastic Fair Queing mechanism


#for more control over the layout

$ns duplex-link-op $n0 $n2 orient right-down
$ns duplex-link-op $n1 $n2 orient right-up
$ns duplex-link-op $n2 $n3 orient right

#Create two CBR agents

#--------------------------------------------------------
set cbr0 [new Agent/CBR]
  $ns attach-agent $n0 $cbr0
  $cbr0 set packetSize_ 500
  $cbr0 set interval_ 0.005

  set cbr1 [new Agent/CBR]
  $ns attach-agent $n1 $cbr1
  $cbr1 set packetSize_ 500
  $cbr1 set interval_ 0.005

  set null0 [new Agent/Null]
  $ns attach-agent $n3 $null0

$cbr0 set fid_ 1
$cbr1 set fid_ 2
#--------------------------------------------------------

$ns connect $cbr0 $null0
$ns connect $cbr1 $null0


$ns at 0.5 "$cbr0 start"
$ns at 1.0 "$cbr1 start"
$ns at 4.0 "$cbr0 stop"
$ns at 4.5 "$cbr1 stop"

#Call the finish procedure after 5 seconds simulation time
$ns at 5.0 "finish"

#Run the simulation



$ns run


I will appreciate if any one could figure out what exacltly is the error
and how to resolve it.
thanks
nitin

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Nitin Nagar                            
Graduate Teaching Assistant                                                           
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