The Virtualization Architecture

The virtualization of wireless adapters is implemented by the MultiNet Protocol Driver that is placed as an intermediate layer, between IP and the MAC. This driver exposes the wireless LAN media adapter as multiple always active virtual wireless LAN media adapters, one per desired network. The IP stack sees all the adapters as always active even though at the driver level only one is active (connected) at any given time. Other than exposing virtual adapters, the MultiNet Protocol Driver is also responsible for switching the wireless cards across the different networks, and buffering packets for networks that are currently inactive.

Figure 1: Modified network stack

Figure 1 illustrates the virtualization of a WLAN card when a user wants to connect to 3 wireless networks. The MultiNet Protocol Driver exposes 3 virtual adapters, and all of them appear active to IP although only Network 2 is active at the instant shown in the figure.