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What is a mesh network?
The internet as it currently exists is mostly organised according to a client/server model. Servers run the web services and store the data and clients are the laptops, desktops and other devices accessing the servers. In a mesh network there isn't any clear division between clients and servers. The computers on a mesh network are known as "peers" and they can perform the functions of both clients and servers. Commonly this is also known as a "peer to peer" network.
The client/server and mesh network models have advantages and disadvantages. If the server in a client/server system fails then you can have catastrophic service outages which affect many users. If a peer in a mesh network fails then the other peers may be mostly unaffected and communications can continue. The disadvantage of mesh networks is that each peer relays data for other peers and so the bandwidth usage by each peer may be higher than for a client in a client/server system. However, with modern hardware that's not much of an issue.
Mesh networks are useful for building local and highly resillient communications infrastructure which can be put together rapidly, in situations where the ordinary internet is either unavailable or untrustworthy.
Example use cases would be:
- Conferences / Exhibitions
- Local community networks, not run by telcos or ISPs
- Emergency services / Disaster relief
- Camp sites
- War zones
- Scientific expeditions to remote areas
- Onboard ships
- Underground (mines/caves)
- Protests
The Freedombone Mesh
The Freedombone mesh is offline - in the sense of not being part of the larger internet - and consists of a set of computers with the system installed communicating wirelessly using ordinary wifi. Peers can enter or leave the network and it will adjust automatically. All communications between peers is end-to-end encrypted, so although it's easy to join the network it's not easy to passively evesdrop.
Installation
Two types of system
Installation is split into two categories, routers and user devices.
A router is a computer which is dedicated to moving network traffic and building out the mesh infrastructure. It's not primarily intended to have a user interface. Hardware such as the Beaglebone Black is ideal for this, because it's small, inexpensive and doesn't consume much electrical power and so can be fitted in any location where an electricity supply is available. Small computers can also be battery operated or solar powered so that the mesh need not be statically sited. They could be included in a backpack for camping, fitted within moving vehicles, or on protest placards to help provide a local and transient communications system.
User devices are the computers with which you would typically access the internet - laptops, desktop machines, netbooks or any other device which can run a Debian-based distro with a working wifi connection.