Virtual WiFi helps a user connect to multiple IEEE 802.11 networks with

one WiFi card. VIt works by exposing multiple virtual adapters, one for

each wireless network to which connectivity is desired. Virtual WiFi

uses a network hopping scheme to switch the wireless card across the

desired wireless networks. Switching between networks is transparent to

the applications, such that the user feels she is connected to multiple

wireless networks simultaneously. Virtual WiFi is implemented as an

NDIS intermediate driver, and a user-level service in Windows XP.

Virtual WiFi interacts with the card device driver at the lower end,

and network protocols at the upper end. The buffering protocol is

implemented in the kernel and the switching logic is implemented as a

user-level service.

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