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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