Help: How to monitor packet drop?

[Yiqun Chen <yqchen@info.sh.cn>]

Hi,

I use QueueMonitor to count the total packet drop of a RED queue as the
following:

set f  [open drop.tr ]
set qmon_ [$ns monitor-queue $node_(r1) $node_(r2) $f]
....
set num [$qmon_ set pdrops_]

but the given value is the number of  forced packet drop,
not including the number of early packet drop.

what is wrong?
Thanks.

Yiqun Chen.