On Sat, Feb 12, 2005 at 02:16:09AM +0000, Andy Furniss wrote: > > >Are we all on the same page as to what the problem is? Any more > >thoughts on how to tackle it? I'm still not convinced that delaying > >ACK's is really any better than the current option to buffer incoming > >data. > > I suppose the gain for marco is that he will not just be delaying acks - > OK he could do the same for data and I agree that there isn't much > difference and it could be better to work with date in some ways eg. you > can really drop whereas with acks it would be harder to simulate a drop.
note that drop means 'losing correct data already received'. so when we drop, we need a retransmission, so we are wasting bandwidth. btw, simulate a drop is easy just send two (or three - it depends on the implementation of the tcp stack) duplicate ack that means: we have received out of order packet so please retransmit. > I don't think he will be just buffering though - thats the advantage for > him - to build in intelligence to handling the problem of shaping from > the wrong end of a bottleneck without the handicap of using dumb queues > that are seeing traffic that's allready shaped by a fifo and whose fill > rate is determined by what percentage of the fifo rate you set their rate. yes, that's the idea. > I guess the receiving machine TCP stack gets it earlier so the > >app looks more responsive, but other than the lower lag I don't see much > >difference really? > > > >Curious to hear how your project gets on though! Please keep us informed! > > Me too - Thomas Graf is also playing with delaying acks - see the dummy > replacing imq thread this & last month on a netdev archive. > > I also remember seeing another shaper that uses delay pools for acks > bandwidth arbiter or arbitrator IIRC. If you can't find it say, I > probably have it squirreled away somewhere on my old PC. thank you for those references. ciao ciao. -- BOFH excuse #270: Someone has messed up the kernel pointers _______________________________________________ LARTC mailing list / LARTC@mailman.ds9a.nl http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/
