[ns] queue management

[abadrah@tachys.com]

Hi,

My question concerns this topology
#  
#  
#    Q_s --- Q_d --- Q_out
#

And the source code is attached in a separate file (aa.tcl).

I am trying to create Queue objects  Queue/DropTail and to attach them to
links like bellow 

set srcQueue [new Queue/DropTail]
set destQueue [new Queue/DropTail]

# Links creation
$ns duplex-link $Q_s $Q_d 4Mb 1ms $srcQueue 
$ns duplex-link $Q_d $Q_out 0.90Mb 5ms $destQueue

But I have the following error :
=====================================
ns arrow 10 10 1000
invalid command name "Queue/_o19"
    while executing
"Queue/_o19 create _o21 "
    invoked from within
"catch "$className create $o $args" msg"
    (procedure "new" line 3)
    invoked from within
"new Queue/$qtype"
    ("default" arm line 3)
    invoked from within
"switch -exact $qtype {
ErrorModule {
if { [llength $args] > 0 } {
set q [eval new $qtype $args]
} else {
set q [new $qtype Fid]
}
}
intserv {
set qtyp..."
    (procedure "_o3" line 10)
    (Simulator simplex-link line 10)
    invoked from within
"_o3 simplex-link _o10 _o13 4Mb 1ms _o19"
    ("eval" body line 1)
    invoked from within
"eval $self simplex-link $n1 $n2 $bw $delay $type $args"
    (procedure "_o3" line 8)
    (Simulator duplex-link line 8)
    invoked from within
"$ns duplex-link $Q_s $Q_d 4Mb 1ms $srcQueue "
    (file "arrow" line 113)                          
=====================================

My objectif is to access to the queue attached to a given link ($Q_d
$Q_out) in order to stop sending 
packets from Q_s depending in the state of this queue (for example when it
is not full).

Is it the right way to do it ? 
Thanks for your help.
Ahmad.


=============================================
Ahmad BADRAH

Performance Modeling Architect
e-mail : Ahmad.Badrah@tachys.com
phone  : +33 (0)4 92 94 48 18
Tachys Technologies
Les Algorithmes, ABS BP 29
06901 Sophia-Antipolis Cedex

http://www.tachys.com