Re: [ns] a bug of ns-2.1b7?

[kunchanl <kunchanl@pollux.usc.edu>]

I ran your program and everything seemed fine. What
tcl/tk version you're using?

Kun-chan Lan

On Tue, 30 Jan 2001, Ming Feng wrote:

> Hi ns people,
> 
> I have met a few "bus error"s when I run some examples
> on ns-2.1b7. The most recent one is the following example:
> 
> 
> ____________________________________________________________
> 
> #Create a simulator object
> set ns [new Simulator]
> 
> #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 $nf
> 	#Execute nam on the trace file
>         exec nam out.nam &
>         exit 0
> }
> 
> #Create two nodes
> set n0 [$ns node]
> set n1 [$ns node]
> 
> #Create a duplex link between the nodes
> $ns duplex-link $n0 $n1 1Mb 10ms DropTail
> 
> #Create a UDP agent and attach it to node n0
> set udp0 [new Agent/UDP]
> $ns attach-agent $n0 $udp0
> 
> #Create a CBR traffic source and attach it to udp0
> set par0 [new Application/Traffic/Pareto]
> $par0 set packetSize_ 210
> $par0 set burst_time_ 0.005
> $par0 set idle_time_ 0.005
> $par0 set rate_ 200k
> $par0 set shape_ 1.5
> $par0 attach-agent $udp0
> 
> #Create a Null agent (a traffic sink) and attach it to node n1
> set null0 [new Agent/Null]
> $ns attach-agent $n1 $null0
> 
> #Connect the traffic source with the traffic sink
> $ns connect $udp0 $null0  
> 
> #Schedule events for the CBR agent
> $ns at 0.5 "$par0 start"
> $ns at 4.5 "$par0 stop"
> #Call the finish procedure after 5 seconds of simulation time
> $ns at 5.0 "finish"
> 
> #Run the simulation
> $ns run
> _______________________________________________________________
> 
> 
> 
> 
> I tried to use GDB to trace the error. I have got the following
> information:
> 
> 
> =================================================================
> warning: Lowest section in /usr/lib/libintl.so.1 is .hash at 0x74
> 
> Program received signal SIGBUS, Bus error.
> 0xa3264 in RNGImplementation::next ()
> =================================================================
> 
> 
> Some of the upper levels of the function calls are:
> 
> 
> ===========================================================
> #0  0xa3264 in RNGImplementation::next ()
> (gdb) up
> #1  0xa32d4 in RNGImplementation::next_double ()
> (gdb) up
> #2  0xb052c in POO_Traffic::next_interval ()
> (gdb) up
> #3  0xafc20 in TrafficGenerator::start ()
> ===========================================================
> 
> 
> I would like to provide three important points:
> 
> 1. The whole example runs ok in ns-2.1b5.
> 
> 2. If I comment out the code part for "creating the CBR 
> traffic source and attach it to udp0", then no error accurs.
> 
> 3. My operating system is SunOS 5.7.
> 
> Does this indicate a bug of ns-2.1b7 related to random 
> number generating? I could not find the answer in the FAQ, 
> ns-problems page, and manual. Can anyone help me to solve 
> this problem?
> 
> Thanks in advance.
> 
> Ming Feng
>