In your letter dated Fri, 29 Jul 2011 04:38:12 +0200 (MEST) you wrote: >Mark Andrews wrote: >> Martin Rex writes: >> > Mark Andrews wrote: >> > > >> > > More correctly it is try the first address and if that doesn't >> > > connect in a short period (150...250ms) start a second connection >> > > to the next address while continuing with the first. If you have >> > > more that 2 address you do something similar for the next one >> > >> > Happy eyeballs means that a clients reaction to congestion is >> > to perform an DoS attack, flood the network with additional >> > connection requests and hammer the server with many additional >> > half-open connections that will never actually get used. >> >> It is not a DoS attack. The client is almost certainly going to >> make those connection attempts anyway if the path is congested >> enough to cause the first connection attempt to fail. The only >> difference is the application gives up in 30 seconds rather than >> 60 or 90 seconds by doing the attempts serially. > >150...250ms ?! > >For a satellite link you already have started 3 parallel connects >in non-congested(!) situations. > >just some random IPv4 pings from my office (in germany) >_without_congestion_: > > ping www.asus.com.tw 300-380ms > ping south-america.pool.ntp.org 280-370ms > ping oceania.pool.ntp.org 340-420ms > ping www.eff.org 160-170ms > ping www.ietf79.cn 330-450ms > ping www.ietf76.jp 270-370ms > >So your approach is already hurting the network without congestion! There are two ways to do Happy Eyeballs. A simple immediate solution that works in most cases to use a fixed timeout value. In your case, you would have to increase that value to a bit higher than 400ms. If HE was invented a long time ago, then by now there could have been a parameter in DHCP to let the network control this parameter. The other way of doing HE is make it react to observed connect time. In that case if you are regularly connecting to sites that are more than 400ms away then the parameter will automatically increase to that value. The proposal is currently discussed in v6ops and everybody seems to be happy with it. So a critical voice may help shape the proposal a bit. _______________________________________________ Ietf mailing list Ietf@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf