Multiple Wireless Networks with one Wi-Fi Card!

You’ve experienced it before. You’re at work, you need to copy files from one file server to the other, but your misconfigured network infrastructure means you need to connect to one wireless network, copy the files to your hard drive, disconnect, connect to the second network, and then transfer. Or maybe you’re at home, and you want to erm.. “borrow” some files off your neighbor’s unprotected wireless network and upload them through your internet connection. Either way, you had to spend a lot of time connecting and disconnecting, associating your card with first one network access point then another. But you don’t have to, because there is another way.

Microsoft Research‘s “VirtualWiFi” utility could do with a better name and could definitely use a lot better marketing, because this amazing utility let’s you connect with one wireless card to as many separate wireless networks as your bandwidth can support – yet no one knows about it!

What’s even more amazing is what this represents – another part of Microsoft that no one knows about: the open source half. VirtualWiFi is the only program of its kind, letting a user connect to a theoretically unlimited number of wireless networks with only one network card – regardless of what wireless card you use or the type of network! The implications alone are amazing.

The $100 Laptop that’s gaining media attention will be using something just like this (although they haven’t got that far yet) to create what is called a “mesh network” where in many wireless cards connect together and through one-another connect many PCs simultaneously without the use of a router – ad hoc networking taken to the next level.

You can also use this to double or triple your internet speed if you connect to two (or more!) seperate APs (provided you have the right software accelerator utilities installed locally) with just one card!

We’ve been using this at the (really cool!) NeoSmart Labs for quite a while, ever since it’s initial release a while back. It seems to work fairly well, at any rate, the kernel driver is stable and doesn’t crash often (almost never), can handle a load really well, and emulates multiple cards very well. It works with most cards we’ve used, but several times we had to use alternate drivers (normally the stock Broadcom Wireless a/b/g drivers), and it seems to work all right. It may be worth the time to look at Microsoft’s own list of verified and/or troublesome drivers.

Microsoft VirtualWiFi is open-source. Yes – open-source as in free, open-source as in the source-is-available-for-you-to-download-change-and-use and open-source as in Linux-like free! The terms of Microsoft’s own open source license (“Shared Source” License) are very similar to the now famous Creative Commons (Attribution-NonCommercial-ShareAlike) licenses; here is an excerpt.

You may use, copy, reproduce, and distribute this Software for any non-commercial purpose, subject to the restrictions in this MSR-SSLA … You may also distribute this Software with books or other teaching materials, or publish the Software on websites, that are intended to teach the use of the Software for academic or other non-commercial purposes … You may not use or distribute this Software or any derivative works in any form for commercial purposes.

1. That you will not remove any copyright or other notices from the Software.

3. That if you distribute the Software or any derivative works of the Software, you will distribute them under the same terms and conditions as in this license, and you will not grant other rights to the Software or derivative works that are different from those provided by this MSR-SSLA.

4. That if you have created derivative works of the Software, and distribute such derivative works, you will cause the modified files to carry prominent notices so that recipients know that they are not receiving the original Software.

Besides being a wonderfully powerful and useful program that’s full of innovation, it shows a side of Microsoft that’s rarely talked about today, and it means that this can be taken to the next level: refined, integrated, used, and published thanks to the Open Source initiative.