Before starting out here is a warning: rental devices from NTT and internet providers like So-net are constantly being updated with firmware updates, backend services running on them are constantly updated as well. NTT Router IPv6 and PPPoE IPv6 settings shown in online documentation may not match router settings of the most recent firmware versions. Also remember that rental NTT router models are different depending on your connection plan.
When in doubt confirm with NTT Flets or your internet provider tech support.
I have a NTT Flets Hikari Phone + ‘Mansion’ internet connection plan with So-Net as the internet provider. As I wrote in the first piece, IPv4 traffic is extremely congested in my local area which So-net tech support checked and confirmed. So-net suggested their free IPoE IPv6 option service as a possible solution.
Unfortunately my AirPort Express Base Station was not very good routing IPv6 traffic. Even in Bridge mode most of the network traffic outside of YouTube remained stuck in the clogged IPv4 stream. This makes sense as AirPort was conceived in the IPv4 era and Apple isn’t updating the software features anymore. The So-net IPoE IPv6 support site mentions that Apple routers “may not be compatible.”
The So-net site does list NEC, BUFFALO and I-O DATA WiFi Routers that are compatible with IPoE IPv6. The key is IPv6 Bridge / IPv6 Pass-Through support which all of them appear to have.
Instead of buying my own WiFi router to replace the AirPort Extreme however, I decided to rent a So-net WiFi router preconfigured for IPoE IPv6 service and DS-Lite (IPv4 over IPv6). The So-Net WiFi router is free for the first 7 months, ¥400 a month there after. So-net tech support said I could return the router at any time in the first 7 months, no questions asked. These things can change so be sure to confirm any rental agreement with your internet provider.
NEC, Buffalo and I-O DATA WiFi Routers can be configured for DS-Lite and Map-E as well but after a year of wrangling with AirPort Extreme configurations, I was done with doing my own IPv6 setup.
I ran with both AirPort Extreme and the So-net rental WiFi router for a few weeks until I was sure IPoE IPv6 and DS-Lite were working OK, then pulled the plug on AirPort. The only tweak on the So-net WiFi router side was renaming the default WiFi network names and login passwords.
The final step was shutting off PPoE on the NTT router. PPoE is a IPv4 only legacy technology and leaving it on can hamper DS-Lite/IPoE performance. The easiest thing to do is reset the NTT router to factory defaults and do not set it up for PPoE.
There are some simple ways for NTT Flets and So-net customers to confirm if IPv6 running correctly:
1) NTT Flets IPv6 Speed Test site If IPv6 is configured correctly you can access the site and test NTT Flets connection speed.
2) Download the Ookla SpeedTest App from the Mac App or iOS App Store. If So-net IPoE IPv6 and DS-Lite are correctly configured your should see “INTERNET MULTIFEED” as the home network name.