On Fri, Apr 17, 2015 at 12:28 PM, Brian E Carpenter <brian.e.carpen...@gmail.com> wrote: > On 17/04/2015 15:17, Erik Kline wrote: >> On Thu, Apr 16, 2015 at 7:41 PM, Phil Mayers <p.may...@imperial.ac.uk> wrote: >>> On 16/04/15 01:57, Lorenzo Colitti wrote: >>> >>>> For the avoidance of mystery: Google performs measurements of IPv6 >>>> connectivity and latency on an ongoing basis. The Google DNS servers do >>>> not return AAAA records to DNS resolvers if our measurements indicate >>>> that for users of those resolvers, HTTP/HTTPS access to dual-stack >>>> Google services is substantially worse than to equivalent IPv4-only >>>> services. "Worse" covers both reliability (e.g., failure to load a URL) >>>> and latency (e.g., IPv6 is 100ms worse than IPv4 because it goes over an >>>> ocean). The resolvers must also have a minimum query volume, which is >>>> fairly low. >>> >>> >>> Lorenzo, >>> >>> Thanks for the response. >>> >>> Do you know if Google have given any thought as to how long they might find >>> it necessary to take these measures? Years, indefinitely? >>> >>> Just curious. >> >> It seems to keep on finding things, so... > > But the incentive is wrong. Forcing users to drop back to IPv4 offers > no incentive to fix the IPv6 problem. The correct incentive would be to > tell an operator that they will be blacklisted unless they fix {X and Y}.
We almost never know what X or Y are. We only detect that there appears to be a problem.