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Build a Wireless ISP on Linux
JuiceMan wrote to mention an article that goes into the the specifics of setting up a Wireless Internet Service Provider (WISP) using Linux and a few easy scripts. From the article: "Wireless clients will have questions, and the Linux-based management tools I'll discuss will help you answer them. Here are some quick examples of how you can answer typical user questions - Question: 'Is the Internet down today? Why can't my browser find www.flakyhost.com?' Solution: First, check your wireless network with the scanap script; it will tell you about the wireless signal quality of all associated clients, including the one that's giving you problems. Then, check IP connectivity with the pingall script; it will tell you about the latency to your ISP's gateway, the DNS, and all your clients, including the problematic one. If these two scripts establish that your network is OK, try www.flakyhost.com."
For a WISP, it's a different story than for a wired line ISP. A WISP only has so much bandwidth for a given frequency whereas a wired line ISP can keep adding massive bandwidth. In order to make a tower site cost-effective, "overselling" the bandwidth is the only way to go at low cost consumer prices. The law of averages says that at any one time, not everyone will be pulling data.
If someone resells to their neighbors, then they will be more likely to peg their bandwidth slice all the time. As someone else made mention, it isn't a big deal if it is a commercial account because the WISP probably charges a premium for a CIR on the bandwidth as opposed to charging a minimum for a consumer MIR.
CIR = Confirmed information rate (guaranteed bandwidth)
MIR = Minimum information rate (best effort bandwidth)
I run a slightly larger ISP than the article author, but he's really nailed the essence of it.
In the commercial world, you run carrier grade gear, with SNMP built into it, but I still have original (two+ year old customers) with WET-11 radios installed, and the author's script worked great.
The most important thing I've learned running a WISP is that people treat it like a utility. When they turn the tap, they expect water, when they flip the switch, they expect light, and when they click "Go", they expect the internet. As the WISP operator, the sooner you stop treating it as a hobby and start treating your service like a utility, the longer you'll keep happy customers. Automating checks and finding problems before they occur is exactly how to do that.
WET-11s usually fail in two stages, with Stage 1 being a gradual degredation of packet success rate, usually after a "close" (1/4 mile) lighting strike. Stage 2 takes about 4 weeks to reach,and it's total failure. The sooner you catch the degredation, the faster you can respond and keep your customers happy. The article author's scripts aren't too hard to extend and automate to make that happen.
John Gorkos
Wildcat Wireless ISP
DeSoto, KS
The best way to build a WISP with a WRT54G is using the Freifunk Firmware (based on openwrt.org) which builds a routed mesh network with any WRT54G flashed with the same firmware. It is really simple and totally open and free - unlike the Sveasoft weenies. Some howtos on my blog:
How to setup OLSR (a mesh protocol) with Freifunk firmware on a WRT54G
Sharing broadband with a WRT54G
Really simple antennas for the WRT54G