Nortel Romances Roaming
Okay, sounds good -- but Nortel's partners may have more to say about when and where this is available. This is complicated stuff, and it turns out that all of the features that enable seamless roaming may take longer to develop. Mobility Networks Systems, the startup that is providing Nortel with the software and hardware that integrates access to WLAN hotspots and GSM/GPRS networks, says that initially, only some of the technology promised in the press release will be available.
The technology will allow a carrier to authenticate a user roaming on a wireless LAN hotspot by checking SIM card details against the home location register (HLR) subscriber data base held on the backend of its cellular network, according to Naveen Dhar, VP of marketing and business development with Mobility. And carriers will be able to use the software to grab information from the access point so that a subscriber can be charged on one bill for time spent on local networks and cellular networks.
However, the first iteration of the Nortel equipment will not enable a user to seamlessly roam, something that involves a radio handoff, between local- and wide-area networks, according to Dhar. "They're looking at handoffs as the next phase, not as the initial phase," says Dhar. "Initially, it is all about customer ownership."
Here at Unstrung we take "seamless roaming" to mean the ability to move out of range of a wireless LAN hotspot and have the data "call" transferred to a wide-area wireless network without dropping the connection, or having to change IP address, or any of that junk.
"Our software can do that," claims Dhar. However, he says that Mobility Networks does not see much of a market for such capabilities until wireless handheld devices are widely available that support both wide-area and local connectivity. The common laptop user, Dhar reckons, will be happy with the ability to reliably log on to access points and get charged for all their wireless usage on a single bill.
So will the new networks seamlessly roam between wide-area and local hot spots? Nortel still says yes, but it's being vague about the timing.
Dave Murashige, vice president of wireless strategic marketing with Nortel, told us via email that the GSM/GPRS variant of this technology is available immediately, with CDMA support to follow in the first quarter of next year and UMTS in the middle of 2003.
"We have created the environment that will allow our operator customers to enable the seamless interoperability between wireless hot spots and 2G/3G networks today," he wrote in answer to our question about when we could expect to see initial commercial deployments of this technology. "The exact timing and implementation of this linkage will be best determined by our operator customers based on their business plans/strategies moving forward."
So then, what's Mobility Network talking about when they said the initial release won't handle roaming?
"The reference to 'seamless roaming' was meant to explain our ability to offer the same IP services -- keyed to individuals -- in either environment," says Murashige.
In other words, says Murashige, a user with Nortel's Contivity client could log on to a WLAN with the PC at the airport, and upon arrival could log on using a 1XRTT phone as a modem in the hotel.
In other words, the end user would be switching devices to roam between the networks. But from the operators' point of view, they could anchor each of these sessions using common equipment in their networks.
This is "seamless in implementation, not temporally," says Murashige.
"As to when true handoff will be implemented, this is more of a market question vs. a technical one," Murashige adds. "As mentioned, we can demonstrate that capability today, but the number of commercial devices that support mobile IP using two radio protocols simultaneously is severely limited."
— Dan Jones, Senior Editor, Unstrung www.unstrung.com