Switches don't eliminate the need for handoffs altogether. Unless every AP in a network is linked to the same switch, the switch will at some point need to transfer connections to another switch. Without such a handoff, networks suffer from what Proxim calls the lobby problem: As people enter a building, their connections are initially routed through whichever switch handles the AP closest to the front door. Unless they can be transferred seamlessly to other switches as they move to different rooms and floors, their traffic will continue to be routed through the lobby's switch all day.
The IEEE is working on a standard for handoffs known as 802.11r, but this is unlikely to be completed before 2006. In the meantime, every Wi-Fi vendor will continue to use a different proprietary mechanism, forcing network managers to build their networks from a single vendor's switches. And since there are no standards for connecting switches to APs, they'll also need that single vendor's APs, too.
The notable exception is Cisco, which can't do interswitch handoffs at all. In Cisco's defense, its switch is so large that few customers need handoffs. It supports up to 300 APs, 10 times as many as some of its competitors. But it also costs at least 10 times as much, though thanks to a modular design it can be used for other functions such as routing and Ethernet switching.
Most networks don't yet have enough APs to require Cisco's giant switch or its competitors' handoff schemes, but VoIP might push them closer to that point. This is because voice usually requires wider coverage than data. Though people don't often surf the Web in corridors or elevators, they expect their phones to work everywhere.
Improving coverage entails more than just buying APs and switches. It also means redesigning the entire network, as most vendors require adjacent APs to use different radio channels to avoid interference.
Discover the benefits of scalable backbone and network services for application and cloud providers.
Network automation is gaining momentum. Here's how you can drive this powerful technology to its full potential.
Subsea cable alternatives can provide a level of comfort for those concerned about disruptions. Realistically, they will continue to play a small, but critical role in the short term.
