The Internet is a network of networks. An Inter-Net. (And keep in mind that the Internet is way more than “The Web” which is just one service running within this gigantic infrastructure.)
The Role of the ISP — Individuals and companies who have their own networks interconnect those nets by plugging in through Internet Service Providers [ISPs]. And in turn, each ISP is linked to “upstream” network providers, and through those to a group of very large carriers who form what’s called the Internet backbone. It’s not just a two-dimensional backbone, but itself is a distributed network of very-high-speed carriers with real-world physical interconnection points. There are many possible routes from an end user to another end user through this backbone. The big providers do what is called peering at these interchange points, where they are all peers, handing off traffic from one to the other with the flow based, of course, on how much traffic is going in any given direction, but otherwise “equally” in terms of priority. [Read more…]