A mesh network is a team of APs that interact with each other on their radio side. All APs are on the same channel. All APs are aware of the Radio Frequency ( RF ) and network performance parameters of other meshed APs within radio range. All APs report information on their neighbors; received signal strength, network throughput and other parameters.
Mesh networks are Ad Hoc networks. There is no central AP that all others must associate with. Every AP in a mesh network is also a client of its neighbors. Each AP reports the number of clients it has associated with. The mesh creates a self-healing network that routes network traffic based on the workload of the APs in use and the RF performance of the meshed APs. Only one AP needs to be connected to a wired LAN to give the mesh clients access to that LAN.
You can create an inexpensive mesh network with Linksys WRT54G routers and freifunk firmware. Freifunk network APs can be configured on the CAT5 side, but not through the wireless interface. You can plug a different ISP into any router. The clients will connect to the internet through the nearest router with Internet access. If any ISP fails, the clients will connect to the nearest working ISP when they refresh their browsers. Free. Easy to configure.
Freifunk networks are open and unsecured. If you need access control, you need to configure that by inserting a server between the ISP and a mesh router, or by using VPN on all auhorized clients
The range of the mesh network is the combined area of all the APs. Some overlap is necessary to form a mesh, but the combined coverage of a dozen APs is much larger than the coverage of one AP.
Enterprise grade mesh networks use two radios per node. One radio uses 5.8 gHz for the mesh, the other provides 2.4 gHz access to the end users. This reduces overhead and data packet collisions. Mesh network, step by step:
Mesh networks are best explained graphically: A large drawing of a Freifunk network in Leipzig http://db.leipzig.freifunk.net/uptime/png/ Things to remember:
Links: English Wiki Freifunk Firmware (English) freifunk-texas.net How To page with an outdated firmware link ( use the link below for newest firmware )
- A typical one AP wireless network has one point of failure; the AP
- A failure of one AP is not a problem in a mesh network
- A mesh network can cover a much larger area than one AP
- Mesh networks are self generating and self healing
the latest firmware at the time this was written: Index of /ipkg B.A.T.M.A.N. A 44 page .PDF description of a large Freifunk net in Africa