[ns] using filter,can any body find the error in this code?

[noorbakh]

Hi 

My problem is in the filter part,becasue it doesn't do any filtering.
also there is no syntax error in this code,but a logic error.
do you know how to use filter command for filtering packets?

thanks
Eaman


On Wed, 10 Jan 2001, Tarik Alj wrote:

> first you are using deprecated stuff : Agent/CBR should be 
> Application/Traffic/CBR and should run over an Agent/UDP.
> 
> second I would look into :
> $n4 attach $filter
> 
> and
> 
> $filter set offset_ [PktHdr_offset PacketHeader/Common size_]
> 
> is the syntax there correct, considering your code is deprecated?
> 
> You might want to change your Null agents for LossMonitors so you could easily  
> check wether they receive packets at all, that's "equivalent" to trace-all 
> thought.
> 
> Last you could run gdb and see what happens...
> 
> >Date: Wed, 10 Jan 2001 10:22:32 -0800 (PST)
> >From: noorbakh <noorbakh@usc.edu>
> >To: ns-users@isi.edu
> >cc: eaman_n@yahoo.com
> >Subject: [ns] using filter,can any body find the error in this code?
> >MIME-Version: 1.0
> >
> >
> >hello every body,
> >
> >we used this peace of code in NS for filtering some packets but it
> >doesn't work properly, can anybody say what is the problem with that?
> >it doesn't filter any of the packets.
> >
> >thank you
> >Eaman
> >
> >
> >#Create a simulator object
> >set ns [new Simulator]
> >
> >#Open the nam trace file
> >set nf [open out.nam w]
> >$ns namtrace-all $nf
> >#Define a 'finish' procedur
> >proc finish {} {
> >        global ns nf f1 
> >        $ns flush-trace
> >	#Close the trace file
> >        #close $nf
> >	#close $f1
> >	#Execute nam on the trace file
> >	#exec nam out.nam &
> >	$ns flush-trace
> >        exit 
> >}
> >
> >$ns trace-all [open output.tr w]
> >
> >set n0 [$ns node] 
> >set n4 [$ns node] 
> >set n5 [$ns node] 
> >set n6 [$ns node]
> >set n7 [$ns node]
> >
> >$ns duplex-link $n0 $n4 1Mb 100ms DropTail
> >$ns duplex-link $n4 $n5 1Mb 100ms DropTail
> >$ns duplex-link $n4 $n6 1Mb 100ms DropTail
> >$ns duplex-link $n5 $n7 1Mb 100ms DropTail
> >
> >
> >
> >set null1 [new Agent/Null]
> >$ns attach-agent $n6 $null1
> >
> >
> >set filter [new Filter/Field]
> >	$n4 attach $filter
> >	$filter target $n5
> >	$filter filter-target $null1
> >	$filter set offset_ [PktHdr_offset PacketHeader/Common size_]
> >	$filter set match_ 100
> >	
> >
> >
> >  set cbr0 [new Agent/CBR]
> >  $cbr0 set packetsize_ 100
> >  $cbr0 set interval_ 0.1
> >  $ns attach-agent $n0 $cbr0
> >  set null0 [new Agent/Null]
> >  $ns attach-agent $n7 $null0
> >  $ns connect $cbr0 $null0
> >  $ns at 0 "$cbr0 start"
> >  $cbr0 set fid_ 1  
> >
> >
> >$ns at 10.0 "finish"
> >$ns run
> 
> -Tarik 										
> 
> 
> 
> 												
> 
> 
> 
>