Subject: [Int-area] Éric Vyncke's No Objection on draft-ietf-intarea-frag-fragile-15: (with COMMENT)

From: Éric Vyncke via Datatracker <[email-masked]>
Date: Fri, 12 Jul 2019 04:55:14 -0700

Éric Vyncke has entered the following ballot position for
draft-ietf-intarea-frag-fragile-15: No Objection

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COMMENT:
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Thank you for the work put into this document, a real problem in the real
Internet

I have a couple of COMMENTs below in the hope to improve the quality of the
document.

Regards,

-éric

== COMMENTS ==

-- Section 2.1 --

"An Internet path connects a source node to a destination node", what about
multicast? If the document is for unicast, then it should be stated early in
the document.

s/If a link fails,/If a link or a router fail,/

A reference to "see NOTE 1" (using xref/target in XML) would be easier for the
reader. Same for "NOTE 2" of course.

-- Section 2.2 --

"In IPv4, the upper-layer header usually appears in the first fragment" perhaps
the right place to mention RFC 3128 (informational) ?

-- Section 2.3 --

Perhaps explicitly mention that PLPMTUD is therefore more reliable than
ICMP-based PMTUD but not applicable to all traffic?

-- Section 3.1 --

Please add reference to A+P (or better MAP ?) and CGN ? (done only in section
3.3)

More generally, it is not clear for the reader why virtual reassembly increases
the fragility.

-- Section 3.3 --

"NOTE 1" is it the same as in section 2.1? Also add xref/target for the
reader's convenience.

-- Section 3.4 --

Suggest to replace "trailing fragments" by "non-initial fragments" as it is
more accurate.

-- Section 3.6 --

The section title refers to "data rate" while it is rather "fragment generation
rate" (which will of course increase the data rate as a consequence). BTW, I
never thought about that ;-)

-- Section 3.7 --

Is it still the case that "Many implementations set the Identification field to
a predictable value" ? Would it be possible to have some data backing this
statement?

-- Section 3.8 --

AFAIK, RFC 4890 is only applicable to IPv6 ICMP and not to IPv4 ICMP
messages... please rewrite this part.

-- Section 3.8.1 --

s/ICMP rate limiting/ICMP generation rate limiting/

Also RFC4442 is IPv6 specific. Add some text for IPv4 ?

-- Section 3.8.2 --

Unsure what the "zone-based" has to do with the content of this section.

-- Section 3.8.3 --

It may be worth adding that the paths TO and FROM the anycast DNS server can be
different, hence, causing the described problem.

-- Section 3.8.4 --

While actually correct, this would also mean that BCP38 is not implement in
this network.

-- Section 6.3 --

"that behavior MUST be clearly documented" unsure whether a "MUST" can be used
for a non protocol action.

-- Section 6.5 --

"MAY rate limit ICMP messages" please state "MAY rate limit the generation ICMP
messages"

Unsure how "Network operators SHOULD NOT filter IP fragments " can be
implemented as non-initial fragments have no UDP/TCP ports... Doing statefull
filtering is probably undoable. Even with a SHOULD this is probably too
restrictive.

== NITS ==

-- Section 2.1 --

s/Whlie/While/