On Mon, Nov 24, 2003 at 15:26 +1300, Arron Scott (ascott) wrote:
QoS 101, which may help in understanding what change has occurred.
On the whole, I have sympathy for every provider and vendor in the industry when it comes to Quality of Service issues. This is the same debate that comes up with any QoS implementation and will always affect the end-user in some way.
Why then should the operator choose?
When choosing queueing strategies, policing and shaping, you generally have to run a compromise, it's choosing which compromise to run.
Policing, at last, we leave the illusion of "QoS" behind and start speaking to the subject.
Shaping is usually better, as this causes TCP to "adjust" it's windowing to the best possible throughput and delay is not noticable to the end-user.
Unless the end-user, the customer, the one who pays, isn't interested in throughput... so again, why is the choice made by the operator?
From the other side, UDP hates delay, primarily as the applications running through UDP are sensitive to delay. Voice, gaming and video are all better at skipping a few frames rather than having to wait for data to arrive.
So this will interfere best with video and VoIP, now would there be a conflict of interest here for an incumbent telco who wants to sustain voice over copper and enter the video market? You decide.
I know this is grossly over-simplified, I am happy to talk offline if anyone wants more info, or thinks I am talking BS.
I think, once you drop the "QoS" pretence, and discuss "policing" there is no reasonable criticism that can be levelled at your explanation. "Why We Don't Need QOS: Trains, Cars, and Internet Quality of Service" ObURL: http://www.bricklin.com/qos.htm
Arron Scott Cisco NZ
Hamish. -- Poetry is the revelation of a feeling that the poet believes to be interior and personal but which the reader recognises as his own.