European users of wide-area WiFi networks would be interested to know that Allied Telesyn is planning to deploy a system which would allow them to move from one AP to another without losing a connection. Allied's proprietary technology is already deployed in Asia. The mobile IP system was developed by Japanese company Root and acquired by Allied Telesis Holdings KK earlier this year.
The system is based on Root's proprietary Layer 3 Roaming technology and it enables hand-over of IP connections in wireless networks in a manner similar to the hand-over of voice and data calls in cellular networks. Thus, if a sufficient number of APs are installed along a rail track and the train is equipped with a mobile router, passengers can view streaming video without interruption. The company says that its technology can hand over connections in vehicles traveling at speeds up to 300 kph. (It occurs to me that at that speed Allied will have only race car drivers as customers.) Root's technology is access-technology agnostic.
Root's proprietary system would soon have a competitor: 802.20. The standard is designed to support connections up to 1.5 Mbps in vehicles moving at 120 kph. 802.16e, when it comes, may also pose a challenge to Allied's plans.