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From: Carsten Bormann <cabo@tzi.org>
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Date: Sat, 30 Nov 2019 23:17:33 +0100
Cc: Sebastian Moeller <moeller0@gmx.de>,
 ECN-Sane <ecn-sane@lists.bufferbloat.net>,
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To: Jonathan Morton <chromatix99@gmail.com>
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Subject: Re: [Bloat] [Ecn-sane]  sce materials from ietf
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On Nov 30, 2019, at 15:32, Jonathan Morton <chromatix99@gmail.com> =
wrote:
>=20
> There are unfortunate problems with introducing new TCP options, in =
that some overzealous firewalls block traffic which uses them.  This =
would be a deployment hazard for SCE, which merely using a spare header =
flag avoids.  So instead we are still planning to use the spare bit - =
which happens to be one that AccECN also uses, but AccECN negotiates in =
such a way that SCE can safely use it even with an AccECN capable =
partner.

This got me curious:  Do you have any evidence that firewalls are =
friendlier to new flags than to new options?

Gr=C3=BC=C3=9Fe, Carsten