open mesh networks

Notes for The open mesh networks.

http://www.rlhc.net/blog/2009/06/22/linuxplanet-com-setting-up-a-linux-based-open-mesh-wireless-network-part-1/

Excerpt:

“Mesh networks are a type of wireless network. As you’ll discover, mesh networking is great for blanketing Wi-Fi in larger areas. They are especially useful in places where the environment changes frequently, such as people and walls moving around in malls, trees and buildings growing around an apartment complex, boats moving around the docks, and trucks coming in and out of stops. Additionally, they are perfect for locations and applications where it’s hard to run network cabling.

Instead of having to run Ethernet cables to each of the access points, mesh networks work wirelessly. Only one mesh node (or more for larger networks) must be grounded and plugged into an Internet connection. Other mesh nodes, acting as repeaters, can be placed throughout a building or outdoor area, only requiring power. When someone surfs the web from a repeater, the traffic hops from node-to-node, making it back to a gateway. The hops can vary depending upon the current signal levels among them all. Hence the common saying about mesh, “self configuring and healing”, and why they are perfect for busy areas.

Where does Linux or open source come into play? Well, there’s Open-Mesh, a volunteer-based organization that provides hardware and services for mesh networks. The comparatively low-cost hardware, or nodes, are loaded with open-source firmware.

The service or dashboard is provided for free by Open-Mesh and lets operators manage their mesh networks online. Then for user authentication (username and password-based access) or pay-for-use applications, there’s the free CoovaOM or CoovaAAA services in addition to other paid options.

In this two-part tutorial series, we’ll set up a mesh network using the Open-Mesh gear and services. First we’ll gather the hardware, create a Dashboard account, and configure the network settings. Then in the next part, we’ll experiment with the internal splash page, third-party captive portal, set up web filtering with OpenDNS, and finally install the nodes and test coverage. Now lets get started!

Gathering the Hardware

First you need to estimate how many mesh nodes/routers you need to cover the desired area. Each node provides about the same coverage as a normal wireless router or access point. However keep in mind, each node needs to at least

overlap in coverage with one other node. You can mount them anywhere with a power outlet, however, if the budget and time is limited you’ll probably want to stick with indoor locations.

Don’t forget about pumping in the Internet. You must have at least one node hooked to an Internet connection. You’d then call it a gateway node; other nodes that aren’t directly connected to the Internet are called repeater nodes. For larger locations and networks, you’d use two or more gateways, thus multiple Internet connections would be required. This would provide users with better bandwidth, as each hop between nodes cuts the bandwidth in about half. It would also provide redundancy for the Internet access; one goes down you still have the other.

You can refer to the guide from Open-Mesh for help on designing and deploying your mesh network.

You can use the Open-Mesh line of hardware. Prices range from $29 for lower-grade nodes and $49 for professional-level–both very affordable. The professional node includes the hardware watchdog chip that auto restarts the node when errors or problems are detected. It also supports longer Power-over-Ethernet (PoE) runs. Additionally, it has both a 2dbi onboard chip diversity antenna and a removable external 2.5dbi antenna.

The following features are on both the lower-cost and professional nodes:

•Use of the Open-Mesh Dashboard to control and monitor your networks.
•Dual ESSIDs (network names); one open for the public users and another one that’s firewalled and WPA-encrypted for secure private access.
•Optional splash page feature for the public access that’s fully customizable with the HTML/WYSIWYG editor.
•User authentication and billing options via third-party solutions from Coova.org, WiFi-CPA.com, WorldSpot.net, or any RADIUS server.
•Redirect users after they view the splash page or login.
•Bandwidth (speed) limitation settings for the public access.
•Wireless bridge mode on non-gateway nodes lets you plug in a computer for the public access.
•Automatic firmware downloads and updates.
•PoE support, with longer runs supported by the professional nodes.
•SSH and Telnet redboot access.
You could alternatively flash your own supported equipment with the Open-Mesh firmware. Remember, the node features can greatly impact the design and installation. So make sure you carefully compare the features between the vendors and nodes.

Now when the postal worker drops off the equipment, don’t get ahead of yourself and start installing right off the bat.”