Re: [ippm] Call for Adoption of draft-mhmcsfh-ippm-pam

Dear all,

I don't dispute the importance of this work. However, the scope of this 
work is not clear yet IMO.

  - SLO, sure,  but what's not clear to me is: SLO per customer, per 
service, per class of service, per flow, per application
I found "Precision Availability Metrics (PAM), aimed at capturing 
end-to-end service levels for a flow, specifically the degree to which 
flows comply with the SLOs that are in effect".
So OK, we speak about flow. So what is your flow definition?
- Btw, based on the previous quoted sentence, I don't understand this 
PAM name. No mention of SLA, no mention of flow, no notion of service.
  Basically, you report a service level indicator (SLI). You confused me 
with PAM
- How are you going to report this flow definition, along with the SLI? 
IPFIX key fields? With a YANG model?
This section 6 content is key to understand how to use those SLIs in an 
operational environment

        The following is a list of items for which further discussion is
        needed as to whether they should be included in the scope of this
        specification:

        *  A YANG data model.

        *  A set of IPFIX Information Elements.

        *  Statistical metrics: e.g., histograms/buckets.

- I am not a big fan to specify some level of thresholding in 
specifications.

    *  VI is a time interval during which at least one of the performance
       parameters degraded below its pre-defined optimal level threshold.

    *  SVI is a time interval during which at least one the performance
       parameters degraded below its pre-defined critical threshold.

Based on my experience, most of the time, we don't get the threshold 
values/names right, and we don't get the number of them right.
     ex: violated, severely violated ... why not extremely violated, 
catastrophically violated?
Trying to express, from the measurement aspects, whether the 
observations are SEVERELY impacting (that's the way I read SVI) is not 
the right approach IMO.
This is maybe you open issues in section 6
     * Policies regarding the definition of "violated" and "severely 
violated" time interval.

Bottom line:
Granted, IPPM is about performance metrics but specifying metrics 
without specifying how they will be used in an operational environment 
is not the right way IMO.
I believe the scope of this document is NOT clear enough to be adopted. 
In other words, I don't know what I'm signing for...

Regards, Benoit

On 9/1/2022 7:25 PM, Tommy Pauly wrote:
> Hello IPPM,
>
> As discussed at IETF 114, we’re starting an adoption call for 
> Precision Availability Metrics for SLO-Governed End-to-End Services, 
> draft-mhmcsfh-ippm-pam.
>
> https://datatracker.ietf.org/doc/draft-mhmcsfh-ippm-pam/
>
> The current version is here:
>
> https://www.ietf.org/archive/id/draft-mhmcsfh-ippm-pam-02.html
>
> Please reply to this email by *Thursday, September 15*, to indicate 
> whether you support adoption of this draft.
>
> Best,
> Tommy & Marcus
>
>
> _______________________________________________
> ippm mailing list
> ippm@ietf.org
> https://www.ietf.org/mailman/listinfo/ippm