In message <201107272350.p6RNodKa019978@xxxxxxxxxxxxxxxxxxx>, Martin Rex writes : > Mark Andrews wrote: > > > > Dave Cridland writes: > > > > > > Happy eyeballs - try everything as soon as you can, in parallel. Drop > > > everything else when one does. > > > > 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 (I > > use 1/2 the original timeout, but that is a implementation detail). > > You continue to use the address that works for that session. You > > drop any other connections to other addresses that complete. > > 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. > While this might currently "improve" the end user experience > of clients, it simultaneously adds a deterrant to server operators > to announce IPv6 addresses (even multiple IP addresses -- they're > better of with IPv4 NAT if they have multiple servers at a single > location). -- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: marka@xxxxxxx _______________________________________________ Ietf mailing list Ietf@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf