[mpls] Mirja Kühlewind's No Objection on draft-ietf-mpls-residence-time-14: (with COMMENT)

Mirja Kühlewind <ietf@kuehlewind.net> Wed, 01 March 2017 16:48 UTC

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Mirja Kühlewind has entered the following ballot position for
draft-ietf-mpls-residence-time-14: No Objection

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----------------------------------------------------------------------
COMMENT:
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High level comment:
Maybe extend the security section a bit and describe what can happen in
the worse case if the value has been modified to a too high or too low
value; and maybe even given some guidance on performing additional checks
to figure out if a given value is reasonable for a given path or not.

Questions:
- Can you explain why PTPType, Port ID, and Sequence ID are needed in the
PTP Sub-TLV format if those values are already in the PTP packet itself
that follows?
- Why is it necessary to define PTP sub-TLV (and have a registry for one
value only)? Are you expecting to see more values here? What would those
values be?
- Similar to Spencer's question: Why don't you also define a Sub-TLV
format for NTP?
- sec 4.3: "RTM (capability) - is a three-bit long bit-map field with
values
      defined as follows:
      *  0b001..."
  Maybe I don't understand what a bit-map field is here but these are
more then 3 bits...?
- also sec 4.3.: "Value contains variable number of bit-map fields so
that overall
      number of bits in the fields equals Length * 8."
  However there is no field 'Value' in the figure... Also the following
explanation about future bit-maps is really confusing to me; why don't
you just say that the rest as indicated by the length field must be
padded with zeros...?
- Should section 4.8 maybe be a subsection of 4.7? This part confused me
a bit because the example seems to be generic but the rest is RSVP-TE
specific, right? Maybe move the example as a separate section before or
after the whole section 4...?

Nits:
- Maybe change to title to: Residence Time Measurement (RTM) in MPLS
network
- There are (still) some not spelled out abbreviations (LDP, PW); in turn
others are extended twice (e.g. PTP)...
- In figure 1, I would rename 'Value' to 'Sub-TLV' and maybe also
indicate it as optional in the figure: Sub-TLV (optional)