NTT Flet’s fails in the Covid traffic crunch

NTT FLET’S internet service has been around forever in many configurations, the latest being Flet’s Hikari ‘optical fiber’. I call it flexible fiber because NTT uses the term Hikari when they should not. My Hikari only comes into the apartment building junction box then branches into each apartment with good old cooper wire phone lines and a VDSL modem. NTT calls that Hikari, I don’t.

PPPoE/IPv4 traffic has been tapped out in Tokyo since at least 2017. When I first upgraded from PPPoE/IPv4 to IPoE/IPv6, I saw a pleasant bump in speed with none of the night time internet traffic meltdowns when using PPPoE.

I thought my problems were solved but over time IPoE/IPv6 download speed has slowed down while iPhone NTT Docomo 4G LTE speed has skyrocketed past NTT Flet’s:

A year ago Twitter user shao, who posts wonderful network and payment tech tweets with the deep tech background to back them up, noted that the Japanese Internet Provider Association was in a collective hissy fit with NTT. IPoE/IPv6 junction points to NTT main lines where tapping out and providers needed more junction points, they also wanted IPoE access pricing brought in line with PPPoE and better traffic control. NTT gave internet providers the cold shoulder with ‘we’ll consider it if you do the work.’ The result of that is NTT East/West Flet’s service is seriously slowing down in face of stay home telework, bored kids streaming content and too much online shopping.

As shao notes 4G and KDDI au Hikari nuro service are, so far, unaffected. The strange thing here is that KDDI is simply renting NTT dark fiber for nuro. So yes, NTT has the capacity, but doesn’t seem inclined to put in the effort to share it unless providers do the work, and also pay up. To be fair I think one of the problems is hinted at in a recent annual NTT financial report: a shortage of field engineers and technicians. Somehow it seems fitting that the human problem of Covid is also the human problem of slow internet speeds.

Choosing the right WiFi router for Japan


When my father had WiFi problems in his apartment, too many dead spots for a decent FaceTime conversation unless he stayed tethered near his Comcast Xfinity WiFi box, I picked up a Linksys Velop mesh WiFi router set for him while in the USA. It could not have worked out better. All the WiFi dead spots were gone, my father can FaceTime wherever he wanders. Velop truly ‘just worked’ out of the box.

Velop and similar ‘mesh’ WiFi routers from Google Nest, Amazon erro et all are good products but I do not recommend any of them for WiFi use in Japan: they all lack support for the IPv6 protocols used by Japanese internet service providers (ISP) who use the NTT NGN backbone…basically everybody.

Goodbye PPPoE (IPv4) Hello IPoE (IPv6)
The problem with Nest, error, Velop is the same one with the outdated Apple AirPort Extreme (part 1, part 2): no support for DS-Lite and Map-E IPv6 protocols used by NTT FLETS. Both DS-Lite and Map-E use IPv6 IPoE (IP over Ethernet) and replace the IPv4 only PPPoE connection protocol.

IPoE is also called IPv4 over IPv6 which means all IPv4 packets are encapsulated inside IPv6. Fast internet connections in Japan use IPv6 but this means that your home router needs to encapsulate everything IPv4 in IPv6 before going out on the NTT internet backbone.

Any router that does not support IPoE/IPv6 on the internet in Japan does not get priority routing at crucial exchange points between local area lines, the ISP, and the NTT backbone. PPPoE is worthless because PPPoE/IPv4 in Japan is ‘tapped out’ and sits in a traffic jam on the local internet highway on-ramp while IPoE/IPv6 get priority and whizzes by on the IPv6 super highway.

Japan Internet Basics
Do yourself a favor and do not waste time and money with any WiFi router that does not support DS-Lite/Map-E protocols and IPoE/IPv6 service. Completely eliminate all PPPoE connection on your home network if you want fast internet service in Japan.

Step 1
Get a free IPv6 service option. All of the Japanese internet providers offer free ‘v6 Plus’ or ‘IPoE’ or similar service options for connecting your home internet directly with IPv6. This is easy to do by phone or online.

Step 2
Get a WiFi router that supports DS-Lite and Map-E, which all routers do that list IPv6 support in the tech specs. The major Japanese WiFi home router manufacturers maintain IPv6/IPoE lists of internet providers and services qualified for their WiFi routers:

Check the qualification list and purchase a listed WiFi router model. I picked up a Buffalo WSR-5400AX6S WiFi mesh router and it worked perfectly out of the box with NTT Flets. The only thing I changed later on was setting my own SSID and network password.

If you are unsure of buying a router you can also rent a pre-configured WiFi router from your Japanese internet service provider. Rental prices vary, So-Net for example charges ¥400 a month. If you are in Japan for the long-term, a good WiFi router investment from the lists above can save you money and give you good internet connections speeds. Happy IPv6 web surfing.