Three good months of learning about wi-fi, writing and re-writing business plans, and networking, and I'm approximately where I was when I wrote the last entry.

But I'm learning a lot.

I started out by evaluating Meraki - they have very nice equipment and a system that is really both beautiful and effective. I was able to get a couple of Meraki nodes on Ebay and put them up on my home network. I can't say enough good about them - the system really works well for providing well-isolated internet access across a geographical area. However, my problem is that I want to distribute a LAN, not just internet access, and Meraki's system does not enable access to your LAN. This is a good thing in a "metro" network (you don't want random folks wandering through your LAN) but doesn't fit into my needs.

I then evaluated Open-Mesh, buying two nodes from Open-Mesh.com. I found some basic reliability problems with them, particularly the well-documented problem of the nodes losing connectivity after a brief poser outage. I actually found mine would not connect if the power was off for less than 20 seconds. When I move or reboot a node, I have to remember to unplug it, go do something else, then plug it in again.

I initially decided that they couldn't access my local network because, while they posessed 192.168.1.x addresses (my local NAT) and I could SSH to them at that address, they were providing DHCP addresses in a different net. The Open-Mesh nodes are also very low-power and not suitable for outdoor use. Given those disadvantages, I decided to put them aside.

I took a look at Ubiquiti's radios, particularly the Nanostation 2. It's a terrific radio - sealed, weather-resistant, with an open-source-derived OS called AirOS for which they provide an entire SDK to suppport the creation of third-party software. It also puts out 26 dBm to either an external antenna (now attached with the "standard" SMA-RP connector) or an internal "adaptive polarity" 10 dBi directional patch antenna. One of the standard features is a Wireless Distribution System (or Wireless Domain System, WDS) implementation with an "Auto" feature that can automatically associate with other nearby WDS radios. They also implement Spanning Tree Protocol (STP) to prevent looping in this sort of an ad-hoc network. This provides the same benefits of B.A.T.M.A.N., the protocol used in Open-Mesh, and just distributes the LAN instead of providing "public" hotspots, client isolation, and other features I don't want or need.

It turns out that there are two problems with this approach. First, the "Auto" feature generates a lot of traffic as the number of nodes increased. With three nodes on "Auto" WDS mode, the traffic overwhelmed my little (factory-spec) Linksys WRT54GS. I was afraid of what might happen when I pushed that up to 10 or 20 nodes.

The second problem is that WPA cannot be used in conjunction with WDS. This is a technical limitation of at least their implementation (see here and numerous other places in the Ubiquiti forums) if not WDS and WPA in general.

This brings me to a conundrum: WEP is not very secure (better than nothing, but still...) and the only way to get WDS to work reliably is to set up the partnering manually.

Now, going back to Open-Mesh, it turns out that you can access the LAN, but it does not seem to be reliable in my network. Sometimes it works, sometimes for some nodes, sometimes it doesn't work, for any nodes. However, if I could get the B.A.T.M.A.N. - RoBIn combo working the way I want, I could load OpenWRT onto the NanoStations and try building a NanoStation OpenMesh node. In fact, I might even try just running B.A.T.M.A.N. and see if I could build what I want without the other parts.

That's where the ag mesh network is as we swing into the Thanksgiving holiday.

More to come...