Re: [ns] dropped packets in diffserv edge router

["Sergio Andreozzi" <sergio.andreozzi@lut.fi>]

Hello Karen,

	as you can see dsREDQueue object is a specialization of Queue object. The
latter is a normal FIFO queue with a default lenght of 50 packets. This
value is used to inizialite a dsREDQueue through the function limit() that
return queue lenght value. You can conclude a phisical dsREDQueue is 50
packets lenght by default.

	Related to your script, policing causes early drop (check edrop), while
buffer overflow causes late drop (check drop). If you turn off policing you
should get 0 packets in edrop statistic, but late drop (drop) should
increase. If you want to reduce this you should increment qlim.

	One tip, remember to configure DROP mode you have to specify max NUMBER of
packets, if you set it bigger than qlim you'll get drop due to buffer
overflow (queue full). You don't change queue lenght setting drop treshold
to 10000000 (it remains 50 packets default), you just specify a maximum
threshold after which you start early dropping (actually the algorithm give
a signal of drop, not edrop; I would change that).

	Anyway it's strange that no packets are enqueued. DSCP values like 00 or 01
are converted to number with function C atoi(); I don't know how this
function behave with number starting with 0. I would change to 0 and 1 in
the script. Just a trial!!!


Regards,


	Sergio