Editing Ends and Means (section)

====Tier 3 Networks====
[[Tier 3 networks]] are essentially resellers - traffic does not cross a tier 3 network, but originates or ends there. A tier 3 network purchases bandwidth from an upstream provider at a [[Point of Presence]], and delivers that bandwidth to end users. They do so either by building a network, or by leasing the requisite lines from an incumbent operator. This type of operation is termed access, or [[last mile]]. 


Conventional last-mile models for broadband delivery are cost effective only in areas with population density above a certain threshold. Those in unserved rural areas must resort to expensive, high-latency satellite solutions, or settle for dial-up speeds.


Access operations are those elements of the communications infrastructure with which the customer comes into contact. These are the lines that branch out from Central Offices into each home or business. In the existing model, these circuits are exclusively vertical - that is, they allow connections only from a client to a service provider, but not from client to client. This prevents the exchange of information in such a way that the service provider does not function as a paid intermediary.


Of the [[Autonomous System|Autonomous Systems]] that make up the Internet, the vast majority are Tier 3 networks. There are upwards of twenty thousand such networks in operation today, generally outside of the United States.