[Lsr] Benjamin Kaduk's No Objection on draft-ietf-ospf-segment-routing-msd-23: (with COMMENT)

Benjamin Kaduk <kaduk@mit.edu> Tue, 16 October 2018 01:58 UTC

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Subject: [Lsr] Benjamin Kaduk's No Objection on draft-ietf-ospf-segment-routing-msd-23: (with COMMENT)
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Benjamin Kaduk has entered the following ballot position for
draft-ietf-ospf-segment-routing-msd-23: No Objection

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COMMENT:
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Thanks for addressing my Discuss point; original ballot comment preserved below.

Can SID be expanded on first usage --
https://www.rfc-editor.org/materials/abbrev.expansion.txt does not list it
as "well known".  (It also doesn't appear to list "Segment Identifier" as
one of the expansions.)

This is basically the same thing I said for the IS-IS document that creates
the MSD types registry, but I'm not sure I followed correctly the meaning
of MSD type 1 for SR-enabled vs.  non-SR-enabled networks.  In particular,
I still don't really understand why it's okay to use the same codepoint for
the max SID depth in SR-enabled networks and for the max label depth in
non-SR MPLS networks.  Why couldn't they just be separate MSD Type
codepoints?

Section-by-section comments follow.

Section 2

                  If the Node MSD TLV appears in multiple Router
   Information LSAs that have the same flooding scope, the Node MSD TLV
   in the Router Information (RI) LSA with the numerically smallest
   Instance ID MUST be used and subsequent instances of the Node MSD TLV
   MUST be ignored. [...]

Unless there is a sorting requirement I've forgotten about, shouldn't this
be "other" rather than "subsequent"?

Section 6

Thanks for the updates in response to the secdir review; they help a lot.

   If the value is larger than supported - instantiation of a path that
   can't be supported by the head-end (the node performing the SID
   imposition).

This is supposed to mean "(instantiation by the head-end) of a (path that
can't be supported)", not "instantiation of a path (that can't be supported
by the head-end)", right?