[Lsr] Spencer Dawkins' No Objection on draft-ietf-ospf-ospfv3-segment-routing-extensions-20: (with COMMENT)

[Spencer Dawkins <[e-mail]>]

Spencer Dawkins has entered the following ballot position for
draft-ietf-ospf-ospfv3-segment-routing-extensions-20: No Objection

When responding, please keep the subject line intact and reply to all
email addresses included in the To and CC lines. (Feel free to cut this
introductory paragraph, however.)


Please refer to https://www.ietf.org/iesg/statement/discuss-criteria.html
for more information about IESG DISCUSS and COMMENT positions.


The document, along with other ballot positions, can be found here:
https://datatracker.ietf.org/doc/draft-ietf-ospf-ospfv3-segment-routing-extensions/



----------------------------------------------------------------------
COMMENT:
----------------------------------------------------------------------

The Introduction would have been much clearer for me if these paragraphs were
much closer to the top of the section - they're at the bottom of the section
now.

  This draft describes the OSPFv3 extensions required for Segment
   Routing with MPLS data plane.

   Segment Routing architecture is described in [RFC8402].

   Segment Routing use cases are described in [RFC7855].

With that change, I'm not sure how much of the discussion in the Introduction
would still be required, but do the right thing, of course.

I'd make the same suggestion for the Abstract,

  Segment Routing (SR) allows a flexible definition of end-to-end paths
   within IGP topologies by encoding paths as sequences of topological
   sub-paths, called "segments".  These segments are advertised by the
   link-state routing protocols (IS-IS and OSPF).

   This draft describes the OSPFv3 extensions required for Segment
   Routing with MPLS data plane.

if it was more than two paragraphs long ...

I am thinking that the reference

  There are additional segment types, e.g., Binding SID defined in
   [RFC8402].

would be more useful at the beginning of Section 3, because that's where you
list the additional segment types, but the reference is back in the
Introduction (with only one example of the segment types).

I'm thinking the SHOULD in this text

  Existing security extensions as described in [RFC5340] and [RFC8362]
   apply to these segment routing extensions.  While OSPFv3 is under a
   single administrative domain, there can be deployments where
   potential attackers have access to one or more networks in the OSPFv3
   routing domain.  In these deployments, stronger authentication
   mechanisms such as those specified in [RFC4552] or [RFC7166] SHOULD
   be used.

is not an RFC 2119 SHOULD that describes interworking, so something like

   In these deployments, stronger authentication
   mechanisms such as those specified in [RFC4552] or [RFC7166] are
   needed.

would be better, but if this IS a SHOULD, I'm curious why you wouldn't use
stronger authentication mechanisms if they're needed. You might want to add
guidance about that, so it's not confused with MUST (BUT WE KNOW YOU WON'T) as
defined in https://tools.ietf.org/html/rfc6919#section-1.

Is there another document that says things like

  Implementations MUST assure that malformed TLV and Sub-TLV defined in
   this document are detected and do not provide a vulnerability for
   attackers to crash the OSPFv3 router or routing process.  Reception
   of a malformed TLV or Sub-TLV SHOULD be counted and/or logged for
   further analysis.  Logging of malformed TLVs and Sub-TLVs SHOULD be
   rate-limited to prevent a Denial of Service (DoS) attack (distributed
   or otherwise) from overloading the OSPFv3 control plane.

? This doesn't seem very SR-specific, although I'm guessing. If there's a
broader document, I don't object to including this guidance here, but adding a
reference to a broader document might be useful.