[PATCH] Add a new TCP_IGNOREIDLE socket option

[Lawrence Stewart]

On 02/14/13 05:37, Adrian Chadd wrote:
> 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.)

This is an area I've thought about and would form the basis for an
interesting applied research project. On a related tangent, we (CAIA)
also have some ongoing research looking at using different CC algorithms
per subflow of a multipath TCP connection.

> 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. :-)

There is quite a bit of relevant literature out there. You could start
with some of the stuff CAIA has had a hand in (e.g. [1]) and follow the
citation trail from there...

Cheers,
Lawrence

[1] http://caia.swin.edu.au/urp/newtcp/papers.html