Re: [PCN] PCN edge behaviour experiment

I don't suggest artifical traffic to cause admitted traffic exceeding 
the PCN threshold but real traffic. A planned experiment does not imply 
artifical traffic.

Am 20.03.2012 22:11, schrieb Tom Taylor:
> Good points. That means the experiment doesn't have to run very long 
> to meet the first two objectives. I do have one concern that if you 
> introduce artificial traffic then maybe you don't get the same outcome 
> that real traffic gives you. I figure it's inevitable that the 
> benefits of PCN with real traffic in a real network will be less than 
> our simulations show, if only because real networks tend to be 
> over-provided with capacity.
>
> On 20/03/2012 4:52 PM, Michael Menth wrote:
>> Hi Tom,
>>
>>
>> Am 20.03.2012 21:18, schrieb Tom Taylor:
>>> I am making what I trust will be the final revisions to the edge
>>> behaviour documents in response to IESG comments. Amongst other
>>> things, this is the text I propose to add in the introduction to
>>> justify the Experimental status of the documents. The text will be the
>>> same for CL and for SM, following on Ruediger's observation that both
>>> behaviours are valid in different contexts. Comments are welcomed.
>>>
>>> ---
>>>
>>> This document describes an experimental edge node behaviour to
>>> implement PCN in a network. The experiment may be run in a network in
>>> which a substantial proportion of the traffic carried is in the form
>>> of inelastic flows and where admission control of micro-flows is
>>> applied at the edge. For the effects of PCN to be observable, at least
>>> some links of the network should be running near or at capacity.
>> Better: "the aggregate rate of admitted flows on some links should come
>> close to the bandwidths of these links."
>>
>>> The amount of effort required to prepare the network for the
>>> experiment (see Section 5.1) may constrain the size of network to
>>> which it is applied. The purposes of the experiment are:
>>>
>>> - to validate the specification of the CL [SM] edge behaviour;
>>>
>>> - to evaluate the effectiveness of the CL [SM] edge behaviour in
>>> preserving quality of service for admitted flows; and
>>>
>>> - to evaluate PCN's potential for reducing the amount of capital and
>>> operational costs in comparison to alternative methods of assuring
>>> quality of service.
>>>
>>> For the first two objectives, the experiment should run long enough
>>> for the network to experience sharp peaks of traffic in at least some
>>> directions.
>> These peaks could be intentionally caused for the sake of the experiment
>> so that the effect of admission control is visible.
>>
>>> It would also be desirable to observe PCN performance in the face of
>>> failures in the network. A period in the order of a month or two in
>>> busy season may be enough. The third objective is more difficult, and
>>> could require observation over a period long enough for traffic demand
>>> to grow to the point where additional capacity must be provisioned at
>>> some points in the network.
>> Also failures could be intentionally caused for the sake of the
>> experiment. Capacity shortage on backup paths could also be planned for
>> so that the effect of flow termination is visible.
>>
>> Best wishes,
>>
>> Michael
>>
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>>

-- 
Prof. Dr. habil. Michael Menth
University of Tuebingen
Faculty of Science
Department of Computer Science
Chair of Communication Networks
Sand 13, 72076 Tuebingen, Germany
phone: (+49)-7071/29-70505
fax: (+49)-7071/29-5220
mailto:menth@uni-tuebingen.de
http://kn.inf.uni-tuebingen.de