[ns] Re: your mail

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

Maybe you can use Manual routing to set
n4-n7 as your preferred route?

Kun-chan Lan

On Fri, 24 Aug 2001, Raj M Verma wrote:

> Hello ns users, I'm trying to run a simulation with
> simple topology having 8 nodes where every node is
> connected to every other node. I've made n7 as the
> destination node where it receicves packets from n0 to
> n6. all the links except n4-n7 are having 1Mb capacity
> to send the data. the link n4-n7 is having a capacity
> of 2Mb to send the data. I'm breaking the link between
> and n2-n7 at a point of time expecting that the
> traffic from n2 shud flow via n4 'cos it's having more
> capacity comparitively with other links. But the
> packets are flowing via n2-n6-n7 and some packets are
> getting discarded 'cos the link between n6-n7 is
> capable of handling only 1Mb of data. shud I add any
> other procedures to make the routers to select the
> optimal route? thanx in advance.
> Raj.
> 
> My code is as follows.
> 
> set ns [new Simulator -multicast on]
> $ns rtproto DV
> $ns color 0 Blue
> $ns color 1 Red
> $ns color 2 Green
> $ns color 3 Orange
> $ns color 4 Yellow
> $ns color 5 Brown
> $ns color 6 Purple
> set nf [open out.nam w]
> $ns namtrace-all $nf
> 
> proc finish {} {
>     global ns nf
>     $ns flush-trace
>     close $nf
>     exec nam out.nam &
>     exit 0
> }
> 
> set numNode 8
> 
> for {set i 0} {$i < $numNode} {incr i} {
>     set n($i) [$ns node]
> }
> 
> $ns duplex-link $n(4) $n(7) 2Mb 10ms SFQ
> 
> for {set i 0} {$i < 7} {incr i} {
>     for {set j [expr ($i + 1)]} {$j < $numNode} {incr
> j} {
> 	$ns duplex-link $n($i) $n($j) 1Mb 10ms SFQ
>     }
> }
> 
> $ns duplex-link $n(4) $n(7) 2Mb 10ms SFQ
> 
> for {set i 0} {$i < 7} {incr i} {
>     set udp($i) [new Agent/UDP]
>     $ns attach-agent $n($i) $udp($i)
>     $udp($i) set class_ $i
> }
> 
> for {set i 0} {$i < 7} {incr i} {
>     set cbr($i) [new Application/Traffic/CBR]
>     $cbr($i) set packetSize_  500b
>     $cbr($i) set interval_ 0.005
>     $cbr($i) attach-agent $udp($i)
> }
> 
> set null0 [new Agent/Null]
> $ns attach-agent $n(7) $null0
> 
> for {set i 0} {$i < 7} {incr i} {
>     $ns connect $udp($i) $null0
> }
> 
> $ns at 0.2 "$cbr(0) start"
> $ns at 0.4 "$cbr(1) start"
> $ns at 0.6 "$cbr(2) start"
> $ns at 0.8 "$cbr(3) start"
> $ns at 1.0 "$cbr(4) start"
> $ns at 1.2 "$cbr(5) start"
> $ns at 1.4 "$cbr(6) start"
> $ns at 3.2 "$cbr(0) stop"
> $ns at 3.4 "$cbr(1) stop"
> $ns at 3.6 "$cbr(2) stop"
> $ns at 3.8 "$cbr(3) stop"
> $ns at 4.0 "$cbr(4) stop"
> $ns at 4.2 "$cbr(5) stop"
> $ns at 4.4 "$cbr(6) stop"
> 
> $ns rtmodel-at 1.5 down $n(2) $n(7)
> $ns rtmodel-at 2.5 up $n(2) $n(7)
> $ns at 4.5 "finish"
> $ns run
> 
> 
> 
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