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?
+ +