[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

RE: [Diffserv] Model - queues - replacement text




Hi, all,

I thought the issue here is simply a terminology problem belonging
to elementary or classic queueing theory.
Reciting any queueing theory book, I deems this pretty clear.
I don't think we are trying to invect any new thing different from 
the basic structure on which all the past theorems are based, are we?

There, queues are a set of buffers and queueing discipline is a rule set the 
servers use to drain the packets out of the queues.
Once the packets are in the queues you could exercise the packets with 
any queue management functions before they packets are drained out by the server(scheduler).
So, the complete system includes three elements: 
1. "ordered data stores" (buffers) + 
2. queue management functions (discarding, re-ordering, thresholding...) + 
3. scheduler (service discipline). 
Thus, Grenville's view is accommodated and Dan's points are covered.
Do I lose any point?


Regards,
Longsong


> From diffserv-admin@ietf.org Wed Dec 15 09:38 PST 1999
> From: "Albert Manfredi" <albert.e.manfredi@boeing.com>
> To: "Andrew Smith" <andrew@extremenetworks.com>
> Cc: <diffserv@ietf.org>
> Subject: RE: [Diffserv] Model - queues - replacement text
> Date: Wed, 15 Dec 1999 10:37:12 -0500
> MIME-Version: 1.0
> Content-Transfer-Encoding: 7bit
> X-Priority: 3 (Normal)
> X-MSMail-Priority: Normal
> X-MimeOLE: Produced By Microsoft MimeOLE V4.72.3155.0
> Importance: Normal
> Content-Transfer-Encoding: 7bit
> X-Mailman-Version: 1.0
> List-Id:  <diffserv.ietf.org>
> X-BeenThere: diffserv@ietf.org
> 
> Andrew Smith wrote:
> 
> > Grenville,
> >
> > There's no point in forming a queue for a bus if there's
> > no scheduling
> > algorithm implied for when the bus comes along. Or are
> > Ozzie bus queues like
> > French ski-resort cable-car queues: form a nice neatly
> > ordered queue and
> > then have a mad random-access scramble when the vehicle
> > arrives. :-)
> 
> Actually, there is. The queue is used for buffering only. I suppose
> you can call that "scheduling," but it really isn't. Buffering means
> you're holding something until the next stage is ready. Scheduling
> means you're holding something for transmitting at some
> predetermined time.
> 
> Thinking back at queueing theory courses, I also remember what Dan
> mentioned, but I think that things like service and arrival times
> can be considered to be outside influences _on_ the queue, which
> affect the behavior _of_ the queue, rather than effects caused by
> the queue itself.
> 
> Semantics, semantics. I am sort of agreeing with Grenville here.
> 
> Bert
> albert.e.manfredi@boeing.com
> 
> 
> _______________________________________________
> diffserv mailing list
> diffserv@ietf.org
> http://www.ietf.org/mailman/listinfo/diffserv
> Archive: http://www-nrg.ee.lbl.gov/diff-serv-arch/
> 
> 

_______________________________________________
diffserv mailing list
diffserv@ietf.org
http://www.ietf.org/mailman/listinfo/diffserv
Archive: http://www-nrg.ee.lbl.gov/diff-serv-arch/