ingress policying for realtime protocol

["Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>]

Hello,

I hope this is the/a right list to ask this question. If not, I'd be
happy to learn the right alternative.

For a system that implements the Media Redundancy Protocol (MRP,
http://en.wikipedia.org/wiki/Media_Redundancy_Protocol) I'm faced with
the task to assert that the corresponding ethernet packets are handled
"in time". Currently this fails already if I do

	scp somebigfile mymrpsystem:

The first idea was to use ingress policying to limit all packets that
are not related to MRP to a certain rate.

The problem in practise however is that the rate that has to be used
above is very low (100kbit) so we're looking for alternatives. I wonder
what's missing to get ingress policying more versatile to allow for
example a prio qdisc or if there is some conceptual problem that I don't
see. I'm not sure this would solve our problem, but it's definitely
something I want to play with before trying/resorting to hackish
solutions (like hacking the eth-driver to pipe MRP packets directly to
the network userspace application instead of through the network stack).

Do you have any ideas or hints?

Thanks in advance
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |