[willis936]

>Empirically, some ISPs route IPv4 more efficiently and some route IPv6 more efficiently.

It is so refreshing to see this written down somewhere. All of the academic papers I've seen comparing the empirical routing performance between IPv4 and IPv6 show a negligible performance difference. However, in the two states I've lived where I have looked at IPv6 vs IPv4 performance I see consistently higher pings with IPv6. Traceroute reveals that each individual hop adds the about the same amount of latency, but there are ~15% more hops for IPv6.

If I play a competitive game then I don't want to be adding 10 ms of latency unnecessarily. So I just disable IPv6 on my gaming rig? C'mon. We can do better.

[rkeene2]

You can thank large backbone providers for this. IPv6 works just fine over the same L2 link as IPv4, so there would never need to be any more hops than IPv4 (sometimes they do need to upgrade equipment to support IPv6 so they may be DIFFERENT hops over DIFFERENT L2 links, but they could also move their IPv4 traffic to that new equipment).

What happens is when the large backbone providers have disputes, the de-peer with each other IPv6, which causes rerouting to be visible. They can't "punish" the other with IPv4 depeering, since that would make their own customers angry.