JSI Tip 9829. Connecting to multiple IEEE 802.11 networks with one WiFi card?

VirtualWiFi is a virtualization architecture for wireless LAN (WLAN) cards. It abstracts a single WLAN card to appear as multiple virtual WLAN cards to the user. The user can then configure each virtual card to connect to a different wireless network. Therefore, VirtualWiFi allows a user to simultaneously connect his machine to multiple wireless networks using just one WLAN card. This new functionality introduced by VirtualWiFi enables many new applications, which were not possible earlier using a single WLAN card. For example,

In more recent work, we have explored two more applications of VirtualWiFi. The first application, which is a very useful tool for fault diagnosis and recovery in infrastructure wireless networks, is called Client Conduit. Client Conduit is a tool that provides a thin pipe of communication between disconnected clients and back end servers that perform wireless diagnosis and recovery. The thin pipe is achieved by running VirtualWiFi on the connected clients. These clients dynamically connect to disconnected clients over an ad hoc network, and send messages from them to the back end servers. VirtualWiFi enables this thin pipe without requiring the connected client to explicitly disconnect from the infrastructure network. A more detailed description of Client Conduit can be found in the paper titled: "Architecture and Techniques for Diagnosing Faults in IEEE 802.11 Infrastructure Networks".

The second application of VirtualWiFi that increases the capacity of wireless ad hoc networks using orthogonal channels is called Slotted Seeded Channel Hopping (SSCH). SSCH uses VirtualWiFi to virtualize a wireless card with as many instances as the number of orthogonal channels. It then connects each virtual wireless card on a different orthogonal channel. Furthermore, SSCH proposes a novel scheme of partial synchronization that can be used with VirtualWiFi. The details of the SSCH protocol are described in another paper, titled: "SSCH: Slotted Seeded Channel Hopping for Capacity Improvement in IEEE 802.11 Ad-Hoc Wireless Networks".

We have implemented VirtualWiFi over Windows XP. The current version is a prototype implementation of VirtualWiFi, and we are in the process of making our software more robust to include more features. Your comments are very welcome.

To learn more about VirtualWiFi, see