QOS/TOS in carp/freebsd in general

[Nick Wolff]

On Mon, Apr 16, 2018, 6:55 PM Lee Brown <leeb at ratnaling.org> wrote:

> On Mon, Apr 16, 2018 at 1:27 AM, Tom Jones <tom at erg.abdn.ac.uk> wrote:
>
> > 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.
> >
> > You can already do this with ipfw?
>
> setdscp cs7 from me to 224.0.0.18
> _______________________________________________
> freebsd-net at freebsd.org mailing list
> https://lists.freebsd.org/mailman/listinfo/freebsd-net
> To unsubscribe, send any mail to "freebsd-net-unsubscribe at freebsd.org"
>

You can do this in ipfw but not in pf as far as I'm aware. While having the
ability in firewalls is great to me that is an administrative flexibility
tool. I think it's important that we have the right code paths to handle
this without workarounds. This is also a update of current code paths that
brings us up to date with 20 years ago and adds the functionality for IPv6
where it was never implemented.

>