On Wed, 24 Sep 2014, David Lang wrote:
The problem is that you don't know what the connectivity is going to be. (unless you are connecting to the same IP as an existing connection). Your first few hops are fairly predictable, but after that you have no idea if you are going to be connecting to a server on a low bandwidth link, one behind a very congested router, or one with better connectivity than you have.
I am not saying that we *know*, but we might have a pretty good idea. Better than to do the same thing regardless of circumstances. If I know my home connection is 250/50 megabit/s, then there is no reason to treat it like a 0.1 megabit/s connection or a 10GE connection.
using fq_codel on every bottleneck link will make TCP work pretty well across that entire range of connectivity
Well, that'll fix one thing, but for instance the IW4 and IW10 debate. I'm sure IW10 works *great* on a 100/100 megabit/s connection when the server is 10GE connected, but it's less than optimal for a 0.1 megabit/s connection.
So why can't the client hint the server that, hmm, I seem to be on a fairly slow connection here, don't send me too much at once? Or it can hint that hey, it seems most times I get pretty large TCP window sizes, so it's ok to start with IW10?
-- Mikael Abrahamsson email: [email protected] _______________________________________________ Bloat mailing list [email protected] https://lists.bufferbloat.net/listinfo/bloat
