[PATCH] Add a new TCP_IGNOREIDLE socket option

Adrian Chadd adrian at freebsd.org
Wed Feb 13 18:37:54 UTC 2013


On 13 February 2013 02:27, Andre Oppermann <andre at freebsd.org> wrote:

> Again I'd like to point out that this sort of modification should
> be implemented as a congestion control module.  All the hook points
> are already there and can readily be used instead of adding more special
> cases to the generic part of TCP.  The CC algorithm can be selected per
> socket.  For such a special CC module it'd get a nice fat warning that
> it is not suitable for Internet use.
>
> Additionally I speculate that for the use-case of John he may also be
> willing to forgo congestion avoidance and always operate in (ill-named)
> "slow start" mode.  With a special CC module this can easily be tweaked.

There are some cute things that could be done here - eg, having an L3
route table entry map to a congestion control (like having an MSS in
the L3 entry too.)

But I'd love to see some modelling / data showing competing congestion
control algorithms on the same set of congested pipes. Doubly so on
multiple congested pipes (ie, modelling a handful of parallel
user<->last-mile<->IX<->various transit feeds with different levels of
congestion/RTT<->IX<->last mile<->user connections.) You all know much
more about this than I do. :-)

Thanks,


Adrian


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