Nov 7, 2006

Wireless Mesh with OpenWrt

I've been following the progress with open source firmware wireless routers and the available Linux-based third party firmware variations for some time now. I recently purchased the Asus WL-HDD so I can play a bit with OpenWrt firmware. Be warned that OpenWrt is the least user friendly firmware, so the faint of heart need not attempt to use this particular firmware.

Having used it and played with the configuration for a couple of weeks now I must admin I like it. Although it now comes with a simple web user interface for simple settings, the strength of this firmware is it's shell interface. Pre-made packages are easily installed using 'ipkg', and the available packages are too numerous to list up here.

The small amout of flash memory in the unit (4MB) is, however, a limiting facting when installing new packages. This is also what makes OpenWrt so interesting. It comes with a basic set of software, and you install what you want beyond that. In this way, it is easier to fully take advantage of your hardware (if it is supported) to get the most out of it. Now, I just need a new antenna, a couple more compatible boxes and things will get much more interesting.

If mesh networking is a new term to you, it is the ability for wireless devices to dynamically create and maintain routing between the involved nodes. OLSR is a specific type of protocol that can be used in a mesh, and without an official standard being available yet, OLSR seems to have gained a lot of traction. Originally written as part of a master thesis, the project soon tool on a life of it's own. There are versions for Linux, Windows, and also OpenWRT.

Setting up OLSR, was an interesting experience. It took a while to figure out the details necessary to get it working properly, but when I was done, communication between all 4 nodes (3 WL-HDD's and my router) seemed to work flawlessly. One of the nodes is now installed at my neighbor's house, and this seems to be working nicely.

For those of you who are less technically inclined, Freifunk is a branch of OpenWRT which has incorporated OLSR direcly into the firmware. This is said to work straight of the box. The advantage Freifunk has besides the user friendly aspect to mesh networking with OLSR is they they were able to have the firmware act as both a mesh node and wireless accesspoint simultaneously. I have not yet tried it, but I am sure that is only a matter of time. It definitely sounds very interesting.

Freifunk firmware

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