Subject: [mpls] Tsvart last call review of draft-ietf-mpls-rfc6374-sfl-08

From: Mirja Kühlewind via Datatracker <[email-masked]>
Date: Mon, 25 Jan 2021 06:07:33 -0800

Reviewer: Mirja Kühlewind
Review result: On the Right Track

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I have one high level comment from a TSV point of view regarding RFC8321 below,
however, unfortunately this document is in some places editorially not easy to
follow and there are multiple places in the document where the document appears
to not be ready to proceed out of the working group:

E.g. section 7 contains the following text:

"A number of methods are described.  The expectation is that the MPLS
   WG possibly with the assistance of the IPPM WG will select one or
   maybe more than one of these methods for standardization."

Is the plan still to select one? If not, why are these different formats needed?

Also there is this editorial note in Sec 9.1:

"Editor's Note we need to review the following in the light of further
   thoughts on the associated signaling protocol(s).  I am fairly
   confident that we need all the fields other than SFL Batch and SFL
   Index.  The Index is useful in order to map between the label and
   information associated with the FEC.  The batch is part of the
   lifetime management process."

And in this context also the purpose of section 10 is unclear to me:

"A future version of the this document will discuss the applicability
   of the various methods to pro-active and on-demand Measurement."

One procedural comment: I had to take a look at draft-ietf-mpls-sfl-framework
to look up the concept of SFL which suggests to me that this document should
probably be a normative reference.

Now regarding RFC8321: The marking scheme shown in section 5 seems to assume a
RFC832-like marking. RFC8321 is mentioned (only) in section 8, however, the
discussion there is rather unclear to me. To me it seem that RFC8321 marking is
assumed and as such this should be stated clearly in the introduction,
potentially with a normative reference to RFC8321.

Some nits:
- Sec 5: "acting as proxy data service packets Section 4" -> ... as described
in Section 4...? - Sec 5: "This it is proposed" -> "Thus it is proposed" - Sec
5: "that in the time interval being analyzed, 10 packets always flow." -> Maybe
"that 10 packets are used in each flow in the time interval being analyzed" ...?
   packets always flow.