Re: [Tsv-art] ECMP [Tsvart last call review of draft-ietf-opsec-ipv6-eh-filtering-06]

Wes Hardaker <wjhns1@hardakers.net> Tue, 11 December 2018 20:06 UTC

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From: Wes Hardaker <wjhns1@hardakers.net>
To: Brian E Carpenter <brian.e.carpenter@gmail.com>
Cc: Nick Hilliard <nick@foobar.org>, tsv-art <tsv-art@ietf.org>, OPSEC <opsec@ietf.org>, IETF-Discussion Discussion <ietf@ietf.org>, draft-ietf-opsec-ipv6-eh-filtering.all@ietf.org
References: <CAL9jLaYHVdHr+rVoWeNtXTXgLxbTaX8V9gn3424tvsLW60Kvow@mail.gmail.com> <5E70C208-0B31-4333-BB8C-4D45E678E878@isc.org> <CAN-Dau0go6_Puf0A9e7KBpk0ApJBUvcxYtezxnwNc-8pKJ3PwQ@mail.gmail.com> <4D69FA8E-FB8A-4A16-9CA6-690D8AE33C9E@strayalpha.com> <20181205122142.GJ1543@Space.Net> <F17C4944-09EC-4AAC-84A0-B660E36AAE89@strayalpha.com> <20181205133821.GL1543@Space.Net> <B6280E0C-6B20-43C1-BB34-170FB06F1EF7@strayalpha.com> <20181205135723.GN1543@Space.Net> <54C715AE-8931-4FA9-AA01-2311EB0055F0@employees.org> <20181205164558.GQ1543@Space.Net> <CCFEFC5B-53AE-4079-B64A-A72A71274FAD@employees.org> <cda0e10e-a56d-4598-dcd4-eabeeac52fb0@gmail.com> <a1b478a7-4396-3d9e-0282-c8c66250526c@gmail.com> <f86a07c8-c421-56db-005c-4db3ce4f3fe0@gmail.com> <3744b28c-3a5a-1ce4-9ff7-5374804d332e@gmail.com> <35277330-4743-4690-8ae0-9a9ab7e34f05@foobar.org> <3a182a82-b933-2d9b-52a8-24805717879b@gmail.com>
Date: Tue, 11 Dec 2018 12:06:41 -0800
In-Reply-To: <3a182a82-b933-2d9b-52a8-24805717879b@gmail.com> (Brian E. Carpenter's message of "Fri, 7 Dec 2018 11:16:25 +1300")
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Subject: Re: [Tsv-art] ECMP [Tsvart last call review of draft-ietf-opsec-ipv6-eh-filtering-06]
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Brian E Carpenter <brian.e.carpenter@gmail.com>; writes:

> "By in large, this flow label changing behaviour has been traced to
> IPv6 supporting CPE/firewalls, which change the flow label between the
> initial syn and the ack."
> 
> Broken middleboxes can prevent anything from working properly.

With my <operator> hat on, we have indeed run into a problem where a
small (~ 2%) of IPv6 TCP sessions to us were failing due to FlowLabels
being used in ECMP hashing.  We had to turn off the usage of FlowLabel
in the hashing because of even a small real world impact to end-users.
-- 
Wes Hardaker
USC/ISI