Meshed networks are nothing inherently new, but i know only very few pepole that have played around with it The theory states that a meshed network uses a network topology in which each node (called a mesh node) is able to relay data for the network. In the wild there are big wireless mesh networks utilized to build up a network which is not dependent on the internet and which is used to connect multiple clients in a town - or even across towns. These networks (In Austria: funkfeuer.at and in Germany: freifunk.net) are open for everybody who is interested and willing to contribute. The only thing you have to do is to register yourself an to set up a network node.

Ham radio enthusiasts have also discovered the power of mesh networks because in case of a disaster the provide a cheap and reliable way how to setup a TCP/IP network. Thanks to the properties of mesh networks they are (if there are enough nodes around) very reliable because with the right software the nodes are self-configuring, self-healing and self-advertising which renders the whole setup very failure-tolerant.

The guys from the HSMM Broadband Hamnet website have developed a firmware image which is based on OpenWrt and can be flashed on cheap WRT54GL routers. This software is intended to be used by hamradio operators, but it works also for non licensed guys because the technques behind the firmwares are the same (olsrd) but the HAM radio version is, in opposite to the other imgaes simpler to configure. However: Be sure not to violate any law! If you dont know what you are doing contact one of you local ham radio clubs. They can help you to gain the appropiate knowledge about HSMM and the are also very supportive if you want to make your license. If you want to dig deeper into the world of wireless communication grab a free copy of WNDW (Wireless Networking in the Developing World) a FREE e-book (PDF or  HTML). Once you know what you are doing then you will see that the HSMM software is like a swiss army knife of networking.

Setup procedure

Hardware setup

1. Buy a cheap WRT54GL Router. Currently they are very cheap (~8€/pc. for a used one at my local hardware dealer). Better by a few of them, because otherwise you will not end up with a sinngle node and not with a network.
2. Read the Getting Started guide on the HSMM website. It contains a lot of useful information.
3. Download the HSMM image for the WRT54GL V1.1.
4. Flash it onto the router. The step-by-step install guide shows you how to do this with a WRT54GL.
5. Repeat this for all the other routers.

Configuration

The configuration for each node is simple:

1. Connect your computer to one of the LAN ports of the router. It will assign you a random IP adress.
2. Open the administration website on http://localnode.local.mesh:8080 
3. Press the [Setup] Button - you will be asked for login data. The default username is root and the password is hsmm
4. Enter the name of your node. Usually this is your callsign and some additional description like OE6GUE-MOBILE or OE6GUE-NODE1 or something like that.
5. Enter a new Password for the node and reboot it.
6. After the reboot of the node you have to renew your IP Adress. In Linux a $sudo dhclient eth0 is sufficient and under windows c:\>ipconfig /renew should do the trick.
7. Finished.

Even if there are more settings availabe it is not necessary to modify any of them. All of the settings are explained in the help which can always be accessed under: http://localnode.local.mesh:8080/help.html

Results

I bought 4 routers and it took me ~30 minutes to flash and configure all of them. Everything worked out of the box. I was able to ping devices on the mesh network:

Since it is a pure HAM radio implementation of a mesh network it is by nature very flexible, but it provides NO ENCRYPTION ON THE AIR. So everybody who comes along with a flashed router can join your network. A neat feature was that i was able to join the internet if only one of the clients was connected to my router via the WAN port of the node and the checkbox "Mesh Gateway" was checked. The datapackets always found their way out.

All in all i would say that it is very simple to setup. It is perfectly suited for HAM radio, but the lack of encryption renders it unuseable for replacing your house cabeling - but there are other dirtibutions like dd-wrt where you can have both: encryption AND mesh-networking.