A-roaming we will go: the wish of many IT managers is for seamless and secure roaming between different wireless networks. EAP SIM will help make that happen

Telecommunications International, Feb, 2004 by Wynne Davies

The momentum driving the rollout of public WLAN (wireless LAN) access--the so-called Wi-Fi 'hotspots'--appears to be unstoppable. According to a report from market research firm, IDC, the number of western European wireless hotspots is expected to grow to more than 32,500 locations by 2007, generating total revenue of US$1.4 bn. It also predicts that there will be nearly eight million hotspot users in western Europe by 2007, with the majority of those users logging in to networks in airports, hotels, and restaurants.

Furthermore, IDC's recent study in the Asia-Pacific region showed that the hotspot market has displayed steady growth, nearly 13-fold in subscriber terms, over the last 18 months; it predicts that this PWLAN subscriber market will hit close to seven million subscribers by the end of 2008 with total revenues exceeding US$600 m.

In recent months, there has been a huge amount of activity in this market with all sorts of players getting in on the act. 'The Cloud', arguably one of Europe's largest public access WLAN networks, has plans to take its successful UK strategy of deploying dense, wholesale Wi-Fi networks into Europe and sell capacity to branded service providers like mobile and broadband operators. BT Openzone was one of the first such providers to sign up with the Cloud in the UK. Furthermore, Boingo Wireless, a leading Wi-Fi network aggregator, has signed a deal with The Cloud whereby Boingo's users will be able to access The Cloud's 2,500 hotspots across the UK.

In addition, GRIC Communications, a leading provider of secure enterprise remote access solutions, has announced that it has signed agreements with three major Wi-Fi service providers, immediately adding more than 2,200 live Wi-Fi access locations in five European countries and South Africa to the GRIC TierOne Network. Another major player in this space, iPass, a virtual network operator (VNO) that has built a global internet access network that includes over 2,800 Wi-Fi hotspots worldwide, has announced it has launched roaming agreements with Swisscom Eurospot and ADP Telecom of France. iPass even has an agreement with China Telecom which supplies Wi-Fi to venues such as McDonalds in Shanghai and Guangdong inside Mainland China.

It is not surprising, therefore, that WLAN hotspots are receiving a considerable amount of attention from the mobile cellular operators. Indeed, some mobile operators, such as T-Mobile, are already deploying Wi-Fi compliant wireless LANs in large numbers at various locations in Europe and the US.

Good news, bad news

The increase in the public Wi-Fi global network footprint is not, however, all good news for business travellers. While it may well help them overcome large gaps of non-productivity in their itinerary by providing a reliable high-speed internet connection in airport departure lounges and hotels in particular, the problem is they will most likely have to navigate a variety of services from different wireless ISPs. This means having to cope with multiple authentication requirements and accommodate inconsistent billing relationships from a multiplicity of sources.

Neither is it necessarily good news for the network operator. A public hotspot wireless LAN system requires more than just wireless LAN cards for the terminals and wireless access points. "Although it is relatively easy to set up a hotspot service, it is not easy to generate a certain level of traffic that will provide enough revenue from single locations to be successful in the early stage of the hotspot market," says Evelien Wiggers, senior research analyst at IDC. "Without roaming possibilities to other locations it's hard to sell subscriptions and create a customer base."

It has become clear that for the WLAN hotspot market to reach its full potential, roaming agreements signed between service providers that allow users to seamlessly access multiple networks are crucial. It turns out that this is not simple a matter. There are many technical and commercial challenges to be overcome, including resolving complex security issues in the authentication, data privacy, and message-integrity mechanisms when using a public hotspot

This has led to the formation of the WLAN SmartCard Consortium. The consortium published their first specifications in July and October of 2003 that define a smartcard interface to provide authentication, session key distribution and identity management using a SIM. The humble SIM (subscriber identity module) found in all mobile phones is in fact a sophisticated and intelligent smartcard, capable of a lot more than storing personal phone book entries and identifying the user. This development allows hotspot operators to extend SIM technology for WLAN authentication. It also allows cellular operators to expand services with WLAN while using their existing infrastructure. It utilises industry-endorsed standards for authentication, such as EAP SIM.

What exactly is EAP SIM?

Standard EAP (extensible authentication protocol) is not particularly new; it is a general protocol for authentication that is specified in the IEEE 802.1 x standard that is used not only for wireless communications but also for wired LANs, such as ethernet. EAP is also embodied in the 802.11i draft security specification for wireless LANs and proposed in the latest WPA (wireless protected access) specifications of the Wi-Fi Alliance.