I used AirPort since the first generation in 1999 and always found the AirPort series to be reliable and easy to configure. But starting in mid 2016 I noticed my NTT Flets mansion (PPPoE – VDSL) service slowing down to analog modem speeds at night and during the weekends.
And so began a year-long tech support journey with NTT and internet provider So-Net to find the problem. Many configuration tests, speed tests, and traceroutes later one thing was clear: IPv4 traffic in Suginami Tokyo was chronically congested. It was time to switch to IPv6 service which So-Net offers as a free option.
The IPv6 option came with a warning: “some of our customers have problems accessing sites like Amazon or Rakuten and switch back to IPv4.” I took the plunge anyway and tried using Airport Extreme (Generation 8) via PPPoE bridging and IPv6 tunneling options.
That worked better than the previous IPv4 only setup at first but it wasn’t long before using the internet after 9 pm was impractical. I then tried using Airport Extreme in bridge mode. That helped for a while but nighttime internet speed degraded over time, by summer of 2017 I was back at square one.
Another set of tests later So-Net tech support suggested a So-Net wireless router for free (the first year) “tuned for routing IPv4 over IPv6.” At wit’s end I decided to give the NEC ATERM WG1810HP wireless router a try. Like magic my internet speed problems were over.
Poking through the ATERM settings I noticed everything was preset for DS-Lite, clearly optimized for NTT FLETS. It’s also clear from reading Japanese forum posts that the NTT FLETS transition to DS-Lite has been in place for some time and AirPort Extreme routers are not equipped for the change. With Apple getting out of the wireless router business time to say goodbye to AirPort Extreme. It was a good run.