Tim Niemeyer and Jörg Knapp from Freifunk Franken on the basic idea and network building in Franconia:
More and more people are setting up and maintaining free networks on their own. The basic idea is that each participant offers other participants open peering and free transit.
Every user in the Freifunk network makes his WLAN router available for the data transfer of the other participants. In return, he or she can also transfer data such as text, music and films via the internal Freifunk network or, via services set up by participants, chat, make phone calls and play online games together in the network.
Freifunk networks are hands-on networks and the decentralized concept is very much in the foreground at Freifunk Franken. Most Freifunk participants use normal WLAN routers with adapted firmware. This firmware is based on the well-known OpenWrt firmware, which has been equipped with some special components. These so-called nodes mesh with each other automatically.
Freifunk networks are interactive networks, and the decentralized concept is also very much in the foreground at Freifunk Franken.
We use the BATMAN Advanced Routing Protocol (Better Approach To Mobile Adhoc Networking) for an intelligent and dynamic selection of the route from the client to the router with Internet or VPN connection. This ensures that every client gets the shortest available route.
In order to bridge greater distances, VPN technology is still often used. The Freifunk-Franken backbone, in which the so-called gateway servers of various participants are interconnected, also runs in this VPN network. These gateway servers are connected via a Layer 3 network using OLSR (Optimized Link State Routing), with which the Freifunk Franken network is growing together to form a large Layer 3 network.
Since many gateway servers can route the traffic to the Internet, access to the Internet is also possible.
The gateway servers thus form a network with currently 11 network segments (subnets). The gateway servers work on average at 20 Mbit to 100 Mbit continuous load.