Re: [v6ops] Operational Implications of IPv6 Packets with Extension Headers - implications from new development for EHs

otroan@employees.org Wed, 29 July 2020 10:13 UTC

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From: otroan@employees.org
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Date: Wed, 29 Jul 2020 12:13:03 +0200
Cc: Vasilenko Eduard <vasilenko.eduard@huawei.com>, Fernando Gont <fgont@si6networks.com>, IPv6 Operations <v6ops@ietf.org>
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Subject: Re: [v6ops] Operational Implications of IPv6 Packets with Extension Headers - implications from new development for EHs
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>> I am asking, because may be the question: what to do to mitigate anticipated problem?
> 
> Do not assume EHs will work outside a very well-defined scope (SRv6 
> is an example of "will work, because won't leave the network where
> needed").  If you start work with the goal "must work across the 
> wild Internet", abandon the idea to do this with EH.

Is that significantly different from:

"Do not assume ICMP, IP fragments, or any other transport protocol than TCP port 80,443 or UDP port 53 will work. Do not assume anything but IPv4 will work."

I think the EHs suffer a bit from a chicken and egg problem.
That is, if a cross the Internet EH ever got defined, then networks would adopt to carry it transparently.
I didn't see if this draft got into localising where the breakage happens; at least previous wisdom was that it happened at the edges not in the core.

Anyway I don't quite understand what this document adds to work describing ossification in general and the previous work on operational considerations for EHs.

Best regards,
Ole