Re: [ns] [Q]multiPath and CBR?

[Haobo Yu <haoboy@packetdesign.com>]

DV was broken in 2.1b6. search lloyd wood's post in ns mailing list
archive and ns problems page, please.

On Fri, 10 Nov 2000, Greg Polgo wrote:

> 
> 
> 
> I'm trying to use 'multiPath' to route a packet alternatively.
> Here's topology.
> 
>    0  --  1  --  2  --  4
>              |       |
>              |-  3  -|
> 
> (What I want is to transmit every each other packets
> to 0-1-2-4, 0-1-3-4.)
> 
> But when I use 'CBR' traffic and get a trace (out.tr),
> I found out that 'out.tr' file has only a few lines!
> It looks like CBR is not working,
> or 'out.tr' can't log all the packets.
> To check this, I removed 'multiPath' and 'DV',
> then CBR source is working fine,
> so I had to conclude that there's something wrong.
> 
> Is there anyone who can answer this question?
> Any reply would be appreciated.
> 
> 
> Greg.
> 
> --------- I'm attaching my script ------------
> #Create a simulator object
> set ns [new Simulator]
> 
> #Define different colors for data flows
> $ns color 1 Blue
> $ns color 2 Red
> 
> set f [open out.tr w]
> $ns trace-all $f
> #Open the nam trace file
> set nf [open out.nam w]
> $ns namtrace-all $nf
> 
> #Define a 'finish' procedure
> proc finish {} {
>         global ns nf f
>         $ns flush-trace
>         #Close the trace file
>         close $nf
>         close $f
>         #Execute nam on the trace file
>         exec nam out.nam &
>         exit 0
> }
> 
> Node set multiPath_ 1
> #Create four nodes
> set n0 [$ns node]
> set n1 [$ns node]
> set n2 [$ns node]
> set n3 [$ns node]
> set n4 [$ns node]
> 
> #Create links between the nodes
> $ns simplex-link $n0 $n1 1Mb 10ms DropTail
> $ns simplex-link $n1 $n2 1Mb 10ms DropTail
> $ns simplex-link $n1 $n3 1Mb 10ms DropTail
> $ns simplex-link $n2 $n4 1Mb 10ms DropTail
> $ns simplex-link $n3 $n4 1Mb 10ms DropTail
> 
> $ns simplex-link-op $n0 $n1 orient right
> $ns simplex-link-op $n1 $n2 orient right-up
> $ns simplex-link-op $n1 $n3 orient right-down
> $ns simplex-link-op $n2 $n4 orient right-down
> $ns simplex-link-op $n3 $n4 orient right-up
> 
> #Monitor the queue for the link between node 2 and node 3
> #$ns simplex-link-op $n2 $n3 queuePos 0.5
> 
> #Create a CBR agent and attach it to node n0
> #set cbr0 [new Application/Traffic/CBR]
> set cbr0 [new Agent/CBR]
> $ns attach-agent $n0 $cbr0
> $cbr0 set packetSize_ 500
> $cbr0 set interval_ 0.005
> $cbr0 set fid_ 1
> 
> #Create a CBR agent and attach it to node n1
> #set cbr1 [new Application/Traffic/CBR]
> set cbr1 [new Agent/CBR]
> $ns attach-agent $n0 $cbr1
> $cbr1 set packetSize_ 500
> $cbr1 set interval_ 0.005
> $cbr1 set fid_ 2
> 
> #Create a Null agent (a traffic sink) and attach it to node n3
> set null0 [new Agent/Null]
> $ns attach-agent $n4 $null0
> 
> #Connect the traffic sources with the traffic sink
> $ns connect $cbr0 $null0
> $ns connect $cbr1 $null0
> 
> $ns rtproto DV
> 
> 
> #Schedule events for the CBR agents
> $ns at 0.1 "$cbr0 start"
> $ns at 0.15 "$cbr1 start"
> $ns at 1.0 "$cbr1 stop"
> $ns at 1.2 "$cbr0 stop"
> #Call the finish procedure after 5 seconds of simulation time
> $ns at 1.5 "finish"
> 
> #Run the simulation
> $ns run
> 
> 
> 
> 
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