I just had one idea, about this. what if make iptables module which will make something like enlarged copy of syn packet and send it back to the sender? (another option would be to kill 1 or 2 ack packets for one syn packet this whould force server to reduce speed) that way htb could count upcoming packet and prepare by reducing other connetions speed? of course that synthetic packet will have higest possible priority since it supposed to be appear in future so cant be shaped anyway I will try to add this functionality to my imq module next week probably. ------------------------ connbytes solution is not good for this, it slows down small picture loading in web pages very much, and big downloads get even more "unused" bandwitch. so effect is not good. expecialy that looks bad on network, when pages become incredibly slow, but big downloads fast. ----- Original Message ----- From: "Andy Furniss" <andy.furniss@xxxxxxxxxxxxx> To: "Patrick Petersen" <lartc@xxxxxxxxxx> Cc: <lartc@xxxxxxxxxxxxxxx> Sent: Sunday, April 18, 2004 2:13 AM Subject: Re: Making tcp start transfers slow > Patrick Petersen wrote: > > Hey list > > I have almost gotten my shaping setup up and running as > planned. The > > last barrier seems to be tcp overshooting availible bandwidth > when its > > starting a transfer, and thereby bursting the line, so ping > rises for a > > moment. At least this is my best guess at the problem > :) > > I sortof workaround this using the connbytes netfilter patch to make the > first 80k of new connections go into a short queue limited to 1/3 - 1/2 > of my downstream bandwidth. It works well in the case where the link is > empty apart from a gamestream and someone is browsing '"'heavy .jpg'"' type > web paged. It also helps a bit if there is other traffic - but if there > are enough tcp connections on the go there will be higher latency bursts > caused by new connections as HTB can't throttle until it's a bit too late. > > > > There is a possibility that its just plain old traffic being > bursty for > > some reason.. I am using bittorrent to test this, as it seems > to be what > > stresses the line the most. > > Ahh bittorrent - this is a special case. It uses full duplex tcp - so > may break some upstream shapers, you can assume that a fair number of > your peers have flooded modem buffers - so there could be quite a few > '"'unstoppable'"' packets headed your way. The worse thing about it, though > is that it runs it's own algorithm on allready open tcps - so existing > connections may go back into slowstart. > > > Would it be possible to lower the default window size, and > thereby > > making tcp start up slower, or would this just lower the > overall speed? > > It could help, but may also give you less of a share of a given > uploaders bandwidth. Reducing MTU may also help (if you run BT on linux > it may reduce rwin for you aswell). > > > My efforts so far can be seen here: > > http://tc.schmakk.dk/betashaper > > Had a quick look - Some thoughts: > > I don't think you can catch all BT traffic by marking the BT ports, I > see ipp2p - can you do it with this or maybe do per IP fairness for bulk > traffic? > > Be carefull about priorotising acks - don't all TCP packets after syn > have ack set. Being lazy on a home setup I get away with giving small > packets priority - saves alot of marking :-) > > For ingress shaping - I find it nicer to shape per IP with htb and use > esfq classic to get per tcp fairness rather than esfq on dst which is > going to effectively make many bittorrent connections go into a FIFO, > which could make for more burstiness. > > Andy. > > > > > _______________________________________________ > LARTC mailing list / LARTC@xxxxxxxxxxxxxxx > http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/ > _______________________________________________ LARTC mailing list / LARTC@xxxxxxxxxxxxxxx http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/
