asymetric link

[Karim Benjelloun <kbenjell@caramail.com>]

>
> if you would like to set up something like
>
>     ------------------>
> n0                       n1
>     hello,
>
> if you would like to set up something like
>
>     ------------------>
> n0                       n1
>     <------------------
>
>
> you could go like:
>
> set ns [new Simulator]
> set n0 [$ns node]
> set n1 [$ns node]
>
>
> $ns simplex-link $n0 $n1 2Mb 300ms DropTail
>                          ^^^^^^^^^^^^^^^^^^
> $ns simplex-link $n1 $n0 0.5Mb 10ms DropTail
>                          ^^^^^^^^^^^^^^^^^^^
> of course, for ^^^, you put whatever you need!
>
> hope this helps,
> chris
>

This is exactly what I'm trying to do !!!
For more convenience, here is the script I'm running :

-----------------------
set ns [new Simulator]

set nf [open out.nam w]
$ns namtrace-all $nf

proc finish {} {
        global ns nf
        $ns flush-trace
        close $nf
        exit 0
}

# Nodes
set n0 [$ns node]
set n1 [$ns node]

# Asymetric Link
$ns simplex-link $n0 $n1 10Mb 600ms DropTail
$ns simplex-link $n1 $n0 28.8Kb 10ms DropTail

# TCPs
set tcp0 [new Agent/TCP/SimpleTcp]
$ns attach-agent $n0 $tcp0
$tcp0 set fid_ 0
set null0 [new Agent/TCPSink]
$ns attach-agent $n1 $null0
$null0 set fid_ 1
$ns connect $tcp0 $null0

# FTP
set ftp0 [new Application/FTP]
$ftp0 attach-agent $tcp0

# Colors ...
$ns color 0 Blue
$ns color 1 Red

Application/FTP instproc start {} {
    [$self agent] send 100;
}

$ns at 0s "$ftp0 start"
$ns at 10s "$ftp0 stop"
$ns at 50s "finish"

$ns run
-----------------------

When I run the nam, I notice that the speed of the first
emitted pkt is equal to the speed of the corresponding ack,
which should NOT be the case because the link is asymetric.
Is this a problem related to the link, or to TCP (do I have
to use another TCP ?) ?

Thank you very much, and sorry for disturbing

	Karim



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