Subject: [PCN] Terminology

From: Michael Menth <[email-masked]>
Date: Tue, 10 Jul 2007 08:44:21 +0200

Hi,

I would like to discuss (again) some terminology for PCN. To get things 
done quickly, we stuck in the architecture draft to the working 
nomenclature from the CL draft and left the exact names for further 
discussion. See Section 2 of
http://www.ietf.org/internet-drafts/draft-eardley-pcn-architecture-00.txt
We proposed an alternative nomenclature in Section 1.3 of
http://www.ietf.org/internet-drafts/draft-babiarz-pcn-3sm-00.txt

The main differences are the following four names, all other terms are fine:

"admissible rate" instead of "configured-admission-rate":
It's the rate that CAN be admitted. Then it is self-understood that the 
rate is not measured but configured.

"supportable rate" instead of "configured-termination-rate":
It's the rate that CAN be supported. Then it is self-understood that the 
rate is not measured but configured. Furthermore, an alternative action 
for flow termination is rate reduction for which the name "termination" 
is not appropriate.

"admission-stop marking" instead of "admission-marking":
The meaning of the marking is that admission should be stopped. The name 
"admission-marking" rather suggests the opposite. This is also in line 
with the single-marking approach.

"excess-traffic marking" instead of "termination-marking":
The name "termination-marking" is fine as long as flow termination is 
the only option to reduce the rate of ingress-egress-aggregates when the 
supportable rate of a link is exceeded. However, an alternative reaction 
to this marking is flow rate reduction (although not in this charter). 
Therefore, the name of that marking should be neutral with
regard to the action.

Regards,

    Michael

-- 
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:[email-masked]
http://www3.informatik.uni-wuerzburg.de/research/ngn

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---

From: <[email-masked]>
Date: Thu, 12 Jul 2007 11:43:24 +0100

Hi

It seems more intuitive to me that the terminology should come as "sets"
of very similar terms that relate to the same mechanism. IE related
terms should obviously be related without having to think about it:-

admission control | configured-admissible-rate | admission-marking (&
admission-marked-rate)

termination control | configured-termination-rate | termination-marking

I find it not instantly obvious that your suggested terms are related:
{termination control | excess-traffic marking | supportable-rate} 

A few more comments in-line

Thanks
phil

> -----Original Message-----
> From: Michael Menth [mailto:[email-masked]]
> Sent: 10 July 2007 07:44
> To: [email-masked]
> Subject: [PCN] Terminology
> 
> Hi,
> 
http://www.ietf.org/internet-drafts/draft-eardley-pcn-architecture-00.tx
t
> "admissible rate" instead of "configured-admission-rate":

[phil] the draft actually uses configured-admissible-rate. Dropping
'configured' would be ok with me. 

> for flow termination is rate reduction for which the name
"termination"

[phil] strictly it isn't the rate that can be supported; traffic can be
supported up to the rate configured for the DS class used by the PCN
traffic. It's the rate above which you start termination-marking pkts. 

Perhaps we need something like terminatable-rate or
terminatable-marking?! (I will be back)

Yes, the charter says that after re-chartering the WG "may also consider
to investigate additional response mechanisms that act on
(pre-)congestion information". So your same point could be made that
admission-marking is an inaccurate term, because in the future the WG
might consider an action other than admission control. However,
personally I don't think potential future charter should influence
terminology.

> "admission-stop marking" instead of "admission-marking":

[phil] I don't object too much to admission-stop-marking (or
admission-control-marking) instead of admission-marking. Personally I
find the latter a bit simpler.

> "admission-marking" rather suggests the opposite. 

[phil] isn't it self-understood that pkts are marked at higher traffic
rates and not marked at low traffic rates?

> This is also in line

---

From: Michael Menth <[email-masked]>
Date: Fri, 13 Jul 2007 11:37:20 +0200

Hi Phil and others,

I have the feeling that everybody can live with the term "admissible rate".

Regarding the terms "sustainable or supportable rate" I suspect that 
some people are not happy about them because they implicate some "right" 
to always use that bandwidth although this should rather be an 
exception. I can understand that. The term "configured-termination-rate" 
anticipates the action how the traffic rate is reduced when the 
respective rate is exceeded although options exist, therefore, this 
expression isn't good either. A neutral solution to that problem is 
"tolerable rate" which avoids all the mentioned misleading connotations. 
Any objections?

Regards,

    Michael

[email-masked] wrote:
>> I would like to discuss (again) some terminology for PCN. To get
>>     
> things
>   
>> It's the rate that CAN be admitted. Then it is self-understood that
>>     
> the
>   
>> It's the rate that CAN be supported. Then it is self-understood that
>>     
> the
>   
>> rate is not measured but configured. Furthermore, an alternative
>>     
> action
>   
>> for flow termination is rate reduction for which the name
>>     
> "termination"
>   
>> is not appropriate.
>>     
>
>> The meaning of the marking is that admission should be stopped. The
>>     
> name
>   
>> the only option to reduce the rate of ingress-egress-aggregates when
>>     
> the
>   
>> supportable rate of a link is exceeded. However, an alternative
>>     
> reaction
>