Because mobile carriers are essentially extending their cellular networks to
third-party Wi-Fi networks, they are naturally concerned about quality, reliability
and service levels. VeriSign's Kershaw confirms what Motorola executives
remarked in an earlier briefing: Mobile carriers want assurances that the
organization's Wi-Fi network has the necessary QoS, seamless and ubiquitous
coverage, reliability and optimized operation between handheld device and
access point. Carriers' other concerns include feature parity between Wi-Fi and
cellular networks and handset functionality. SIP, as defined and expanded in
multiple IETF (Internet Engineering Task Force) RFCs, lacks some of the extra
features needed for specific implementations of FMC. Appreciably, SIP is
extensible and, hopefully, that functionality will be rolled into future standards-
body work.
The three universities participating in VeriSign's trial--University of Michigan,
Northwestern University and Texas A&M University--are using faculty and
students as guinea pigs, with the number of users across all the trials
numbering just over a hundred. Similar to what was rumored with the
TalkTelecom deployment in Ireland, this pilot does not use traditional candy-bar
or flip-phone handsets; rather, it is based on PDA-style HP iPaqs that include
GSM and 802.11b support. According to Kershaw, mobile voice usage in the
university setting, encompassing college dorms, classrooms and faculty offices,
is about 60 to 70 percent of the subscriber's total airtime. This is much higher
than the oft-quoted average of 30 to 40 percent in the enterprise space, and it
was a contributing factor in selecting higher education as a place to initiate
these trials. Because some schools have comprehensively deployed their
wireless LANs across their campuses, it might well be possible for students to
spend almost their entire day within proximity of a Wi-Fi access point.
Progress is definitely being made on the wireless convergence front. Although
the market is very young and the supporting technology awkward and
immature, different approaches to convergence are being worked out. The
Motorola/Avaya/Proxim partnership has the advantage of a well-tested and
feature-rich solution with a custom handset that's more acceptable than the
bulky PDA used in the VeriSign trials. Proxim and Motorola have also tweaked
their respective parts so that roaming between Wi-Fi actually works within
acceptable tolerances. But replacing your existing PBX with one by Avaya (or, in
the future, with Cisco's CallManager) is not a lighthearted task. VeriSign does
well by demonstrating an alternative dual-mode solution. Time will tell how these
competing, and sometimes complementing, concepts fair in the marketplace.
