[Cats] draft-ietf-cats-metric-definition-13 early Perfmetrdir review

[Giuseppe Fioccola via Datatracker <[e-mail]>]

Document: draft-ietf-cats-metric-definition
Title: CATS Metrics Definition
Reviewer: Giuseppe Fioccola
Review result: Not Ready

This document focuses on compute and communication metrics for Computing-Aware
Traffic Steering (CATS). It introduces three levels of abstraction: Level 0
(Raw metrics), Level 1 (Metrics combined into categories), Level 2 (A single
normalized metric).

From a PERFMETRDIR point of view, the document does not standardize performance
metrics but it specifies higher-level representations. However, I think that
the document is not ready since the description of the metric registry entries
of section 6 should be improved. Here are some suggestions for your
consideration:

- Section 3.2 introduces Level 0 Raw Metrics. I would also mention the network
performance metrics, which are described in RFC 7799.

- In section 4.1, I would add the metrics type (if the information is
available), based on the classification of RFC 7799. The distinction between
active, passive and hybrid metrics can be a relevant property.

- In section 4.2.1, you could also refer to RFC 5644 in addition to RFC 5835.

- Section 6 defines the registry entries but I have some concerns about the
current explanation and more details are needed. The naming rule includes the
Measurement Method (sections 6.1.3, 6.2.3, 6.3.3, 6.4.3 6.5.3), but it is not
fully described. For example, it is not clear to me what the term Passive
refers to, is it based on the definitions of RFC 7799 and RFC 10014?

- I would also add additional examples for the metrics. Appendix A only
includes Level 0 Metric Examples.