The sale of the 700 MHz spectrum in the USA and attempts to pass network neutrality bills have led to a lot of discussion about open networks, but what does one really look like?
Open communication networks are not new. To a geographer, the term communications has a very broad meaning. Pheidippides running from Marathon to Athens was an early example of an open communications network in operation; the roads and paths he used were unrestricted. This kind of infrastructure was "free" in the libertarian sense: Anyone could send runners with messages, and anyone with a sword could try to stop them.
More recently, we've seen national postal services with special legal protections. These are required by law to carry any message anywhere in a designated area (typically a country) in a non-preferential way, and in exchange they're not held liable for anything they transport.
The Internet has openness as an emergent property rather than as a part of the design. No one owns the modern Internet. More accurately, no one owns all of the modern Internet, but most of it is owned by someone. I own the machine on which I'm typing this article, as well as a co-located server. When I connect from my PC to my server, I connect via cables owned by my ISP and my co-lo company (and a dozen or so others in the middle).
The result is that it's very difficult for anyone to impose strict rules on usage of the entire Internet. My ISP could block some ports, but I could always switch to another ISP. My hosting provider could refuse to allow me to run some services, but I could always switch providers. The backbones in the middle could drop certain kinds of traffic, but they would start losing business.
I just said that I could always switch to another ISP, but that's not necessarily true. ISPs are a natural monopoly—or, at least, a natural oligopoly. I have two real alternatives when it comes to last-mile connectivity: cable or ADSL. The cable network was built with private funds and, due to a recent set of mergers, is now owned by a single entity. The telephone network, over which ADSL runs, was built with public funds by a company that was later privatized. As such, it's subject to quite strict regulation. Local loop unbundling (LLU) rules allow third parties to install equipment at my local exchange and provide their own services over the copper going to my house.
This kind of regulation helps to reduce the barrier to entry for a new ISP. Running cables to every house in an area would be incredibly expensive and would cause a lot of disruption to the local community, so it's in the best interests of the residents to discourage this idea.
What About Wireless?
When wireless enters the picture, the rules change. Wireless Internet connections cost very little to create. Assuming that an available uplink exists, I could build a transmitter in a very small area of land and provide a wireless service to the surrounding area. Exactly how big the area and how fast the connection would be depends a lot on the wavelength I would choose to use.
That's the theory, anyway. In practice, the spectrum is a scarce resource. If I start using a particular band, no one else in range of my transmitter can use it without causing problems for me.
Some bands, such as the 2.4 GHz region, are unregulated. You can do whatever you like in this band—with a few minor restrictions, specifically related to power and antenna size. You could build, say, a mobile phone network using 802.11g (which runs in the 2.4 GHz band), but it would be very expensive, since you'd need to deploy access points every few tens of meters to get reasonable coverage. This plan would be possible for something the size of a corporate or university campus, but for even a small city it's a massive undertaking.
The situation here is somewhat like a party in a large room. Anyone can talk to anyone else, but it's considered rude to shout so loudly that no one else can hear, and you're likely to get kicked out if you keep doing it.
There are other bands that anyone can use, however. The Citizens' Band (CB) allows anyone to use it and has very long range. Restrictions on its use have to do with what you send, rather than how strongly you transmit it. Whether you need a license for CB radio varies from region to region. (And the lack of a license is often disregarded in places where you do need one, as long as you don't interfere with other traffic.) A common restriction, however, is that you must broadcast unencrypted analog voice traffic.
In order to be useful, a truly open network would have to abide by a set of rules defining fair use. If the person with the strongest transmitter could drown everyone else out, that would cause problems. Fortunately, this isn't a new problem. Things like the venerable Ethernet protocol have been designed to allow lots of computers to share a finite amount of network bandwidth. An area of spectrum designated for an open network would require a mandated protocol that handled distribution of bandwidth, and any compliant devices would be allowed to connect.