Wireless mesh networks are self organising and self healing -networks that can be used to connect computers across small and large -areas, depending on the radio technology used. Normal wifi equipment -can be used to create home made radio networks, and there are several -successful examples like -Freifunk and -Athens Wireless Metropolitan Network -(see -wikipedia -for a large list) around the globe. To give you an idea how it -work, check out the nice overview of the Kiel Freifunk community which -can be seen from their -dynamically -updated node graph and map, where one can see how the mesh nodes -automatically handle routing and recover from nodes disappearing. -There is also a small community mesh network group in Oslo, Norway, -and that is the main topic of this blog post.
- -I've wanted to check out mesh networks for a while now, and hoped -to do it as part of my involvement with the NUUG member organisation community, and -my recent involvement in -the Freedombox project -finally lead me to give mesh networks some priority, as I suspect a -Freedombox should use mesh networks to connect neighbours and family -when possible, given that most communication between people are -between those nearby (as shown for example by research on Facebook -communication patterns). It also allow people to communicate without -any central hub to tap into for those that want to listen in on the -private communication of citizens, which have become more and more -important over the years.
- -So far I have only been able to find one group of people in Oslo -working on community mesh networks, over at the hack space -Hackeriet at Husmania. They seem to -have started with some Freifunk based effort using OLSR, called -the Oslo -Freifunk project, but that effort is now dead and the people -behind it have moved on to a batman-adv based system called -meshfx. Unfortunately the wiki -site for the Oslo Freifunk project is no longer possible to update to -reflect this fact, so the old project page can't be updated to point to -the new project. A while back, the people at Hackeriet invited people -from the Freifunk community to Oslo to talk about mesh networks. I -came across this video where Hans Jørgen Lysglimt interview the -speakers about this talk (from -youtube):
- - - -I mentioned OLSR and batman-adv, which are mesh routing protocols. -There are heaps of different protocols, and I am still struggling to -figure out which one would be "best" for some definitions of best, but -given that the community mesh group in Oslo is so small, I believe it -is best to hook up with the existing one instead of trying to create a -completely different setup, and thus this have decided to focus on -batman-adv for now. It sure help me to know that the very cool -Serval project in Australia -is using batman-adv as their meshing technology when it create a self -organizing and self healing telephony system for disaster areas and -less industrialized communities. Check out this cool video presenting -that project (from -youtube):
- - - -According to the wikipedia page on -Wireless -mesh network there are around 70 competing schemes for routing -packets across mesh networks, and OLSR, B.A.T.M.A.N. and -B.A.T.M.A.N. advanced are protocols used by several free software -based community mesh networks.
- -The batman-adv protocol is a bit special, as it provide layer 2 -(as in ethernet ) routing, allowing ipv4 and ipv6 to work on the same -network. One way to think about it is that it provide a mesh based -vlan you can bridge to or handle like any other vlan connected to your -computer. The required drivers are already in the Linux kernel at -least since Debian Wheezy, and it is fairly easy to set up. A -good -introduction is available from the Open Mesh project. These are -the key settings needed to join the Oslo meshfx network:
- -| Setting | Value |
|---|---|
| Protocol / kernel module | batman-adv |
| ESSID | meshfx@hackeriet | Channel / Frequency | 11 / 2462 | -Cell ID | 02:BA:00:00:00:01 | -
The reason for setting ad-hoc wifi Cell ID is to work around bugs -in firmware used in wifi card and wifi drivers. (See a nice post from -VillageTelco about -"Information -about cell-id splitting, stuck beacons, and failed IBSS merges! -for details.) When these settings are activated and you have some -other mesh node nearby, your computer will be connected to the mesh -network and can communicate with any mesh node that is connected to -any of the nodes in your network of nodes. :)
- -My initial plan was to reuse my old Linksys WRT54GL as a mesh node, -but that seem to be very hard, as I have not been able to locate a -firmware supporting batman-adv. If anyone know how to use that old -wifi access point with batman-adv these days, please let me know.
- -If you find this project interesting and want to join, please join -us on IRC, either channel -#oslohackerspace -or #nuug on -irc.freenode.net.
- -While investigating mesh networks in Oslo, I came across an old -research paper from the university of Stavanger and Telenor Research -and Innovation called -The -reliability of wireless backhaul mesh networks and elsewhere -learned that Telenor have been experimenting with mesh networks at -Grünerløkka in Oslo. So mesh networks are also interesting for -commercial companies, even though Telenor discovered that it was hard -to figure out a good business plan for mesh networking and as far as I -know have closed down the experiment. Perhaps Telenor or others would -be interested in a cooperation?
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