Telechat Review of draft-ietf-ippm-ioam-data-12
review-ietf-ippm-ioam-data-12-intdir-telechat-bernardos-2021-03-22-00

Thanks for this document. I think it is well written and well on track. I
include below some comments, mostly from an Internet view point, but not
limited to that.

- I wonder if some SHOULD/MUST language needs to be used in the following
piece, as it talks about important operational considerations:

   "The operator has to consider the
   potential operational impact of IOAM to mechanisms such as ECMP
   processing (e.g.  load-balancing schemes based on packet length could
   be impacted by the increased packet size due to IOAM), path MTU (i.e.
   ensure that the MTU of all links within a domain is sufficiently
   large to support the increased packet size due to IOAM) and ICMP
   message handling (i.e. in case of IPv6, IOAM support for ICMPv6 Echo
   Request/Reply is desired which would translate into ICMPv6 extensions
   to enable IOAM-Data-Fields to be copied from an Echo Request message
   to an Echo Reply message)."

- I think a clarification of how an IOAM domain relates to an administrative
domain (as mentioned in Section 4) is required. It is not clear if they are the
same or an IOAM domain is a subset of an admin domain.

- Are there any privacy concerns due to the fact of the information that IOAM
discloses and can be analyzed by any node in the domain? There is some text in
the Security Considerations, but it does not cover in much detail the new risks
that it opens due to the additional information disclosure for that belong to
the domain.

-Nit: in section 3, some abbreviations follow the approach "XXX: ", while
others "YYY ". Please harmonize it. Example of what I mean below:

   E2E        Edge to Edge

   Geneve:    Generic Network Virtualization Encapsulation
              [I-D.ietf-nvo3-geneve]

Thanks,

Carlos