Muthu –

I agree with the comments from all of the folks who have responded to you thus 
far.
The RFC is specifying what the externally visible behavior needs to be in order 
for the feature to be safely and usefully deployed – it is not specifying HOW 
to implement that behavior.

But, let’s assume for the moment that you are “right” and that the draft 
wording is suggesting that configuration knobs for the thresholds/filters 
should be owned by the IGP.
If, despite this “suggestion”, you were to decide to implement the knobs 
elsewhere (e.g., under the interface) – would it affect interoperability? Would 
it be detectable from the vantage point of another router?

I don’t agree with your interpretation –and I don’t feel that any change in the 
text is needed.
But I do defend your right to implement the knobs wherever you like.

However, before making your decision you might want to consider 
https://tools.ietf.org/html/draft-ietf-teas-yang-te-14#section-3.2 - which is 
relevant from a manageability perspective. Your choice of where to put the 
knobs might indeed matter (though not to the IGP externally visible behavior).

   Les


From: Lsr <lsr-boun...@ietf.org> On Behalf Of Muthu Arul Mozhi Perumal
Sent: Tuesday, June 05, 2018 6:26 PM
To: Robert Raszuk <rob...@raszuk.net>
Cc: lsr@ietf.org; Jeff Tantsura <jefftant.i...@gmail.com>; Stefano Previdi 
(IETF) <s...@previdi.net>
Subject: Re: [Lsr] IGP TE Metric Extensions

Robert,

On Tue, Jun 5, 2018 at 9:28 PM, Robert Raszuk 
<rob...@raszuk.net<mailto:rob...@raszuk.net>> wrote:
​Muthu,​

​How is the measurement interval and filter coefficients described in the draft 
related to dissemination?​

​It is directly related. If you see the title of the section is: "Announcement 
Thresholds and Filters"​

So measurement interval does not intend to describe how often you actually 
measure ... it describes a time window where you report the value (which could 
consist of many measurements actually taken).

​Are you saying measurement interval is a misnomer? The draft clearly 
distinguishes measurement interval from announcement interval:

​   Additionally, the default measurement interval for all sub-TLVs
   SHOULD be 30 seconds.

   Announcements MUST also be able to be throttled using configurable
   inter-update throttle timers.  The minimum announcement periodicity
   is 1 announcement per second.  The default value SHOULD be set to 120
   seconds.​

Yet, it claims measurements are outside its scope..


We intentionally left out this part that does not belong to the igp protocol 
machinery.

​Which of the functionalities described in sections 5, 6, 7 of the draft belong 
to the IGP protocol machinery?


​What draft are you talking about ? I was under impression that we are 
discussing RFCs here.

​Well, both -:) I am referring to draft-ginsberg-lsr-isis-rfc7810bis and I 
believe there is a chance to improve some text in RFC7810..

Regards,
Muthu



​All functionality from sections 5-7 aim to provide machinery to control 
stability of protocol operation. It is one how you measure and this is not part 
of the RFCs. and completely different what and how you advertised derived 
values from those gathered by your measurements. Now keeping in mind that you 
do not advertise when you measure but only when you are allowed by protocol 
rules it should be easy to see the point which Stefano made above.

​Thx,
R.


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