TECH NEWS

Roam Between Wi-Fi and Cellular Networks

Lucent and NetMotion are working to let mobile workers maintain data and application connectivity as they move across various types of wireless networks.

Lucent Technologies, which designs networks for communications service providers, has demonstrated handoff of a wireless data call from a Wi-Fi (802.11) wireless LAN (WLAN) to a third-generation UMTS network (UMTS is based on the GSM cellular standard). Lucent says the capabilities will let mobile laptop users browse the Web while roaming between two network types and avoid interruption in their session.

For the test, Lucent used its 3G UMTS network equipment and a laptop PC equipped with a UMTS test mobile phone, a Proxim ORINOCO 802.11 WLAN card, and ipUnplugged's Roaming Gateway client-server software. With this gear, users were able to initiate a secure Internet session on an 802.11 WLAN or a 3G UMTS network and maintain it while moving from one network to the other.

The capabilities could have a number of implications. For example, Lucent says, someone downloading large files on the road can be sure they won't lose their connection and the related files.

Lucent says the capabilities rely on the Mobile IP standard from the Internet Engineering Task Force (IETF). Mobile IP supports inter-technology handoffs between 802.11 and 3G technologies. (One of the characteristics of 3G wireless technology is "always on" high-speed mobile Internet connection.)

The company has also demonstrated roaming capabilities between Wi-Fi and 3G CDMA2000 wireless networks.

It will use these roaming capabilities in its wireless data products for businesses. The company's UMTS and CDMA2000 networking technology will let mobile workers use laptops and PDAs to tap into business data and applications "behind the firewall" to ensure the same security that in-office workers have.

Other work in roaming technology

NetMotion Wireless () is also looking to improve mobility across networks. The NetMotion Mobility software secures applications running on wireless networks and maintains connectivity to applications and data as the user moves across subnets, various network types (Wi-Fi, cellular, dial-up, etc.), and coverage gaps.

To optimize performance as users move between networks with different bandwidth capabilities, the software automatically switches compression "on" or "off" based on the speed of the wireless interface. For example, users can roam between high-bandwidth 802.11b LANs and lower-bandwidth GPRS or CDPD wireless data networks and be sure they're getting the best data speeds possible.