Date: Mon, 16 Apr 2018 09:27:37 +0100 From: Tom Jones <tom@erg.abdn.ac.uk> To: Nick Wolff <darkfiberiru@gmail.com> Cc: freebsd-net@freebsd.org Subject: Re: QOS/TOS in carp/freebsd in general Message-ID: <20180416082736.GB48822@tom-desk.erg.abdn.ac.uk> In-Reply-To: <CACxAneCODxbgA3qWDqtt%2B_dOZfEmUrCnw_T8eEovZK8a6c5GtQ@mail.gmail.com> References: <CACxAneCODxbgA3qWDqtt%2B_dOZfEmUrCnw_T8eEovZK8a6c5GtQ@mail.gmail.com>
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On Sun, Apr 15, 2018 at 04:30:45PM -0400, Nick Wolff wrote: > Hi, > > I currently have a review in to make carp use dscp values on outgoing > packets. This will make it easier to preform QOS on modern switches as we > have been able to drive carp insane on 10g links while throwing storage > traffic at it.On an interesting side note apparently after 64k mac address > moves for a single mac address in the cam table arista 7050t seems to with > out warning give up and stop moving address but leaves it in the table > where ever it last was. > > I was originally going to just toggle between cs7 and the old TOS low delay > setting. But it was requested that I just make it a settable Integer value. > In this case I'm planning to do 0-63 to match dscp with a default of 54 > (CS7) (Network Control) but you could still set the old value by setting > the sysctl to 4. Anything larger then 64 would be truncated as two shifts > are needed to align with the field leading. > > Does anybody do anything anywhere with the old TOS values like low delay in > there networking infrastructure? Should this be updated in other places in > kernel and userland? It's been 20 years since TOS was deprecated and > replaced with DSCP. > > Any other comments or thought are always welcome. I cannot speak to network stacks, but we have performed some large scale DSCP measurements of the Internet and found TOS semantics still in use. You might want to look up: Exploring DSCP modification pathologies in mobile edge networks: IEEE/IFIP Workshop on Mobile Network Measurement I think there is more work in line to be published based on similar measurement campaigns. > References: > > Open Review - https://reviews.freebsd.org/D14536 > General DSCP reference - https://www.tucny.com/Home/dscp-tos > > > Thanks, > > Nick "darkfiberiru" Wolff > _______________________________________________ > freebsd-net@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org" -- - [tj]
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