[ns] monitoring Q size

[Ishan Mandrekar <ishan@io.ece.drexel.edu>]

Dear NS-users:

I'm looking to monitor the instantaneous queue size, and I have the
following coded to achieve the same:

set q1 [$ns monitor-queue $n3 $n4 1 0.1]
set qlen [$q1 set size_]
puts $qlen

I've put the above lines in a procedure, which is called recursively after
a specific time interval all through the simulation period. Even though I
can see the queue overflowing in NAM, the value for $qlen printed on the
screen is zero throughout.

Am I missing something here?

-Ishan.