frottle: Defeating the Wireless Hidden Node Problem

jasonjordan writes "The West Australian FreeNet Group was the first to go War Flying - and now we've released "frottle" (freenet throttle) - an open source project to control & manage traffic on fixed wireless networks. Such control eliminates the common hidden-node effect even on large scale wireless networks. frottle works by scheduling client traffic by using a master node to co-ordinate - effectively eliminating collisions! Developed and tested on the large community wireless network of WaFreeNet, We've found it has given us a significant improvement in network usability and throughput. "

Comments

Re:Is Frottle.. is good

[Radix999]

Of course. Wireless access points generally aren't geared for large number of users OUTDOORS. The difference is that when you've got users 10-20km away collisions have a lot more effect. Individual clients don't see the traffic of other users, so it's very easy to cause collisions (this is the Hidden Node effect) - there is commercial software to solve this problem (ie. Karlnet), but the large expense and lack of Linux support (ie. use 2.4.2 kernel, Redhat 7.1 and their binary driver or else) put us off majorly.

So we rolled our own. Frottle is the result.

Re:802.11x topology change

[TheZombie187]

It sounds like this is an attempt to change the topology of 802.11x to a polled topology without the true benefit of such topology without changing the hardware.

Correct!

We have built a city-wide wireless freenet using commodity hardware. Things were working well, but as we grew larger the hidden node effect became a larger problem. Swapping all the hardware over is a big expense, and a big undertaking for a bunch of hobbyists.

We did investigate doing so, and also investigated a firmware solution (KarlNet TurboCell) but found it unsuitable to our needs.

On a whim, one of us implemented a small master/slave polling system in Perl which seemed to do the job surprisingly well, and it just grew from there.