Re: [PCN] PCN edge behaviour experiment

[Bob Briscoe <[e-mail]>]

Tom,

Your original text was good, and I agree with the way people have 
converged on improvements so far. I want to  go back to your first 
posting and pick out a couple of other parts of the text...

Perhaps the proposed text is rather too prescriptive about what a 
valid experiment would be. I suggest:

s/The purposes of the experiment are:/
  /Vendors and operators will have their own purposes for conducting 
experiments, but example purposes would be:/

One more comment inline...

At 20:18 20/03/2012, Tom Taylor wrote:
>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.

[snip]

>The purposes of the experiment are:

[snip]

>- 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. 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.

The third objective may not necessarily require a wait for capacity 
to actually be provisioned. The main unknown costs are:
a) cost of implementation and operation of PCN (relative to an alternative)
b) any differences in capacity costs due to differences in feasible utilisation

An experimental deployment is the best way to quantify (a).
But (b) may be sufficiently quantifiable using projections without 
having to wait for capacity to need replacing.



Bob



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________________________________________________________________
Bob Briscoe,                                BT Innovate & Design