On Tue, 14 Jun 2011 10:59:47 -0700 Lorenzo Colitti <lorenzo@xxxxxxxxxx> wrote: > On Tue, Jun 14, 2011 at 10:30 AM, james woodyatt <jhw@xxxxxxxxx> wrote: > > > > Very few of the people using 6to4 in this way will show up in Google's user > > behavior analysis, of course, because Google doesn't run its own 6to4 > > return-path relay as I-D.ietf-v6ops-6to4-advisory recommends. > > > > We would not see these users even if we operated reverse path relays as > recommended in the draft - from the point of view of the server, in both > cases it's just a TCP connection to a 2002::/16 address, regardless of > whether the relay is inside the Google network or outside it. > > Those users would become visible if we added AAAA records with 6to4 > addresses, but that's a bad plan because it would likely lead to the > double-digit connection failure rates that Geoff observes. It would also > become visible if Google operated an open anycast relay, which we do not > plan to do. > I don't know if it is intentional, however if I use Google's public 8.8.8.8 and 8.8.4.4 resolvers, and prefer 6to4 over native IPv4 (via /etc/gai.conf under Linux/glibc), it seems that the video content of all youtube videos is now being delivered over IPv6. The same thing happens if I use my ISP's resolvers - I know they're doing IPv6 work behind the scenes, however I don't know but dont think their resolvers are Google whitelisted. That suggests that if there are hosts out there that blindly prefer tunnelled IPv6 over native IPv4, and have 6to4 available, there is a likelyhood that more people are using 6to4 now than there was before World IPv6 day. I'm having no performance problems at all with any videos I select, including 1080P ones. > > > The way to find these people is to crawl the BitTorrent networks. What's > > that old maxim? "You can't test what you don't measure." Do you measure > > the BitTorrent networks? > > > No, we don't. The measurements we conduct have the purpose of determining > the impact of adding AAAA records to web sites, so we don't measure the > population of users that has 6to4 but does not use it to make HTTP > connections to dual-stack websites. We do measure the impact of 6to4 on the > reliability of websites indirectly, e.g., by observing the difference > between OSes that prefer IPv4 over 6to4 and OSes that don't. > > Also, is there a way we can put this debate to rest using real data? What if > we asked someone like Hurricane Electric how much traffic on their network > is native IPv6 vs. 6to4? > > That said, I would argue that most or all 6to4 traffic could just as well > use IPv4, since both parties to the communication obviously have access to a > public IPv4 address. What is the advantage of using 6to4 over IPv4 that > makes it worth suffering an 80% failure rate? I'm having and have been having 100% success rate (or near enough to it that I can remember) using 6to4 for a number of years, including with an IPv6 MTU of as large as my PPPoE connection will support i.e. my 6to4 tunnel has an IPv6 MTU of 1472. Since noticing that youtube videos are coming over IPv6, I've paid a bit more attention to the "quality of experience" I've had, and have not found any reasons to change my preference back to native IPv4 instead of 6to4. _______________________________________________ Ietf mailing list Ietf@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf