[sfc] Éric Vyncke's No Objection on draft-ietf-sfc-serviceid-header-12: (with COMMENT)

[Éric Vyncke via Datatracker <[e-mail]>]

Éric Vyncke has entered the following ballot position for
draft-ietf-sfc-serviceid-header-12: 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-sfc-serviceid-header/



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

Thank you for the work put into this document.

Please find below a couple of non-blocking COMMENT points and I would
appreciate it if the authors answered to my points that were closed to be a
DISCUSS.

I hope that this helps to improve the document,

Regards,

-éric

-- Section 1 --
Please clarify the following text as NAT only applies to IPv4 and as there is
no private addresses in IPv6 "  Typically,
   because of the widespread use of private addressing in those
   networks, if SFs to be invoked are located after a NAT function, the
   identification based on the internal IP address is not possible once
   the NAT has been crossed. "

-- Section 3 --
While I am not familiar with NSH RFC 8300 and the concept of updating the NSH
context, the following text makes me wonder: "  The classifier and NSH-aware
SFs MAY inject or strip a Subscriber
   Identifier Context Header as a function of a local policy."

It appears to me that a SF would actually increase/decrease the size of NSH
which could lead to two issues: 1) the actual MTU is decreased on the path
*after* encapsulation 2) if ICMP is generated back to the source of the NSH
header, then will the source recognize the NSH packet inside the ICMP message
as it is different ?