[Idr] Éric Vyncke's Discuss on draft-ietf-idr-flow-spec-v6-19: (with DISCUSS and COMMENT)

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

Éric Vyncke has entered the following ballot position for
draft-ietf-idr-flow-spec-v6-19: Discuss

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DISCUSS:
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Thank you for the work put into this document. It is indeed due time to filter
also those IPv6 packets ;-)

Please find below one blocking DISCUSS point, some non-blocking COMMENT points,
and some nits.

I hope that this helps to improve the document,

Regards,

-éric

== DISCUSS ==

I am puzzled by the absence of a flow spec for the first Next-Header being a
specific value and by the absence of a flowspec for the occurence of any
extension header in the extension header chain. Extension headers are an
important difference compared to IPv4 and could be 'nasty' as well (e.g.,
hop-by-hop header). Why was this not considered by the authors ? Or is there
another document in the WG to address this issue ?


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COMMENT:
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== COMMENTS ==

-- Section 3.1 --
Smart idea to have an offset but I wonder whether "Offset < Length < 129" is
true... Esp. with some IPv6 addresses with an embedded IPv4 address (32 bit) at
offset 96. Isn't "Offset + Length <= 128" better ?

-- Section 3.3 --
How is the upper-layer defined here? Basically, how a node can determine
whether it is an extension header or an upper-layer header? While I agree that
there are not too many new upper-layer protocols being specified, I would
prefer to have a definition of "upper-layer" here either by listing (or
referring to a IANA registry) all existing extension headers (then all 'next
header' not being 'extension header' are by default 'upper layer') or
vice-versa.

-- Section 3.6 --
Just curious ;-) Why is bit 7 not used in this encoding ?

-- Section 3.7 --
I share Ben Kaduk's concern about the encoding of the flow label in less than
20 bits.

== NITS ==

-- Section 3.1 (and possibly others) --
Sometimes the field 'length' is all lower case and sometimes it is capitalized.

-- Section 3.8.2 (and possibly others) --
Please use RFC 5952 to write IPv6 addresses.