Elements of Networking: Size

Another defining characteristic of a network is its size.

• At its simplest form, a network can be composed of nothing but two computers and a network cable.

• A typical home network has two or more computers separated from the Internet by a router, which directs internal network traffic and manages connections to and from your Internet service provider. For a description of a typical home network's components, and how each element can represent a section of a much larger network, see Parts of a Network.

• Subnetworks within a larger network share many characteristics with a home network, since they are separated from the rest of the network by some form of routing and make a distinction between computers that belong to the subnet and computers that don't.
  
  Subnetworks usually include many more computers and printers than a home network, and may contain computers from more than one building, but the basic architecture is the same. Access to resources on computers in the subnetwork can be controlled based on whether a request comes from another computer within the subnetwork, from elsewhere in the larger network, or from elsewhere in the world.

• UIUCnet is in a unique position in terms of network size. From the perspective of an on-campus user, UIUCnet resembles a small-scale model of the Internet as a whole: a large group of computers providing a large group of services to users around the world. However, from the perspective of an off-campus user, UIUCnet resembles a very large-scale private network: some features are available worldwide, and others are restricted only to computers that are identified as members of UIUCnet and located within the campus firewalls that control access to on-campus resources.
  
  If you're off campus and need to claim UIUCnet membership for your computer from elsewhere in the city or elsewhere in the world, the campus VPN server can establish your computer's credentials to join the UIUCnet network. (VPN for Wired Users explains why this is valuable.)
  
  
• The Internet is, as its name implies, the largest interconnected network on the planet. While there are some private networks that do not share any connection with the Internet for security purposes, most public and private networks (such as UIUCnet) are connected to the Internet.

Next element: Connection methods