Re: [PCN] Second Last Call for draft-ietf-pcn-architecture

[<philip.eardley at bt.com>]

{ -----Original Message-----
{ From: Michael Menth [mailto:menth at informatik.uni-wuerzburg.de]
{ Sent: 02 October 2008 14:26
{ To: Eardley,PL,Philip,CXR9 R
{ Cc: pcn at ietf.org
{ Subject: Re: [PCN] Second Last Call for draft-ietf-pcn-architecture
{ 
{ Hi Phil,
{ 
{ sorry, I was confused. You are right. I overlooked that this intrinsic
{ contradiction is resolved by redefining the term "PCN-threshold-rate"
in
{ Figure 1 into "PCN-excess-rate" in Figure 2. Thus, the semantic of the
{ term "PCN-threshold-rate" depends on the deployment scenario, right?

it isnt redefined; it isnt an intrinsic contradiction. It's consistent.
different deployment scenarios uses PCN marking differently - this
concept is independent of the terminology. 

{ Again, this is very confusing an I recommend to introduce the two
terms
{ "admissible rate" and "supportable rate" in addition. They are
{ independent of the deployment scenario and allow the explanation of
PCN
{ without having a particular deployment scenario in mind.

Having extra terminology is a possibility. I took the view that each
term that is defined is an extra thing for the reader to understand. It
also requires some mapping between the admissible /supportable rates and
excess/threshold rates. Personally I think this likely to be more
confusing. But if there is a clamour in support of this being added, I
could add it. (Michael, I take your vote in favour as read!)

Phil/

{ 
{ Regards,
{ 
{     Michael
{ 
{ philip.eardley at bt.com wrote:
{ > { -----Original Message-----
{ > { From: Michael Menth [mailto:menth at informatik.uni-wuerzburg.de]
{ > { Sent: 02 October 2008 13:15
{ > { To: Eardley,PL,Philip,CXR9 R
{ > { Cc: pcn at ietf.org
{ > { Subject: Re: [PCN] Second Last Call for
draft-ietf-pcn-architecture
{ > {
{ > { Hi Phil,
{ > {
{ > { I still have concerns regarding the nomenclature in the current
{ > version
{ > { of the architecture draft.
{ > {
{ > { Take Figure 1 on page 10. The terms PCN-threshold-rate and
{ > { PCN-excess-rate are meaningful only in the CL deployment scenario
{ > where
{ > { the reference rate for the threshold marker is the
PCN-threshold-rate
{ > { and the reference rate for the excess marker is the
PCN-excess-rate.
{ > { This is different for the SM deployment scenario where the
reference
{ > { rate of the excess marker must be set to the PCN-threshold-rate.
{ >
{ > This is not correct. The rate of the excess marker is set to the
{ > PCN-excess-rate. Fig 2 shows, for the Single Marking deployment
{ > scenario, how this relates to admission /termination
{ >
{ > Best wishes
{ > Phil
{ >
{ >
{ >
{ > How
{ > { funny is that? No, it's not funny - this is confusing and makes
{ > further
{ > { explanations cumbersome and prone to misunderstandings. I think
that
{ > { this is a bug that should be corrected before publication as these
{ > terms
{ > { help to describe the core idea of PCN. Using the term admissible
rate
{ > { instead of PCN-threshold-rate and supportable rate instead of
{ > { PCN-excess-rate decouples PCN rate thresholds from marking
mechanisms.
{ > { They express the meanings of these thresholds within the PCN
concept
{ > { which are denoted on the right side in Figure 1 and allow a much
{ > clearer
{ > { presentation of the concept.
{ > {
{ > { I hope my reasoning is clear. This document is not a working
document
{ > { for a closed group where nomenclature has no importance as long as
{ > { everybody knows that we mean pears if we say apples - it's a
reference
{ > { for others to learn about PCN and, therefore, technical terms
should
{ > be
{ > { precise and easy to remember.
{ > {
{ > { Regards,
{ > {
{ > {     Michael
{ > {
{ > { philip.eardley at bt.com wrote:
{ > { > {
{ > { > { There are some known edits that have to be made before we can
{ > submit
{ > { > to
{ > { > { the
{ > { > { IESG:
{ > { > {
{ > { > { - Correct references to Internet Drafts to indicate "Work in
{ > Progress"
{ > { > { - Fix formatting errors detected by ID-nits
{ > { >
{ > { > I just fixed these (I think) in
{ > { >
{ >
http://www.ietf.org/internet-drafts/draft-ietf-pcn-architecture-07.txt
{ > { > The only changes from 06 to -07 are to re-format some of the
{ > references
{ > { > in order to fix the above 2 points.
{ > { >
{ > { > Phil
{ > { >
{ > { > Ps to see the -05 to -06 diffs:
{ > { >
{ >
http://tools.ietf.org/wg/pcn/draft-ietf-pcn-architecture/draft-ietf-pcn-
{ > { > architecture-06-from-05.diff.html
{ > { > or from
http://tools.ietf.org/wg/pcn/draft-ietf-pcn-architecture/
{ > { > _______________________________________________
{ > { > PCN mailing list
{ > { > PCN at ietf.org
{ > { > https://www.ietf.org/mailman/listinfo/pcn
{ > { >
{ > {
{ > { --
{ > { Dr. Michael Menth, Assistant Professor
{ > { University of Wuerzburg, Institute of Computer Science
{ > { Am Hubland, D-97074 Wuerzburg, Germany, room B206
{ > { phone: (+49)-931/888-6644, fax: (+49)-931/888-6632
{ > { mailto:menth at informatik.uni-wuerzburg.de
{ > { http://www3.informatik.uni-wuerzburg.de/research/ngn
{ >
{ 
{ --
{ Dr. Michael Menth, Assistant Professor
{ University of Wuerzburg, Institute of Computer Science
{ Am Hubland, D-97074 Wuerzburg, Germany, room B206
{ phone: (+49)-931/888-6644, fax: (+49)-931/888-6632
{ mailto:menth at informatik.uni-wuerzburg.de
{ http://www3.informatik.uni-wuerzburg.de/research/ngn

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