The Wi-Fi Alliance has allied with the Wireless Broadband Alliance to sort out some standards for Wi-Fi roaming, taking its queue from the mobile industry, which does it so well.

The details are still under development, but the idea is that a traveller will be able to just fire up their PC/tablet/smartphone and have it automatically log onto the nearest Wi-Fi network that has a roaming agreement with the home network, just as they can with a mobile telephone – which sounds terrific until one realises how complicated it is beneath the surface.

BT was on hand to lend credibility to the plan, which involves using one of the various Extensible Authentication Protocol (EAP) standards to allow roaming users to securely authenticate themselves without mucking about with password screens and such.

Kit supporting the roaming system will get a "Wi-Fi Certified Hotspot" logo from the Wi-Fi Alliance, but the partners are keen to avoid a publicly-displayed service mark for compliant networks, preferring to assume that every network will join, while admitting that they still have to work out a precedence mechanism for when more than one network is available.

Cellular roaming is hugely complicated by the requirement that the roamed-to network has no access to the encryption keys used to authenticate the user, and this is one aspect that the new alliance plans to emulate though the use of EAP, ideally based on the GSM SIM which can be found in so many Wi-Fi devices these days.

Mobile networks also have to deal with knocking credit off pre-paid tariffs, and tunnelling all data through the home network, neither of which will form part of the proposed Wi-Fi roaming system though some operators are reportedly keen for tunnelling to be explored. That would enable operators to enforce content restrictions, but would also mean we could access the BBC iPlayer when using a Wi-Fi hotspot abroad.

How much users should pay for roaming is another question as yet unresolved. Apparently users don't want to pay by the minute, though that's how BT OpenZone currently bundles its roaming deals. Whether it will eventually come as part of a subscription, or an optional extra, will depend on the home provider and the tariffs it decides to offer.

Equally unclear is how much the operators will charge each other for access. Cellular roaming rates are ruinously high, so much so that the EU had to step in and cap the amount companies were charging each other. The partners expect the low cost of Wi-Fi to be the driving force for adoption, but if roamed-to partners decide to overcharge then that could easily disappear. ®