CertiGuide to Network+  9  Chapter 0000:  Network Basics       9  VI  Private vs Public Networks

VI  Private vs Public Networks 1 Public Networks

A private network is one in which all devices on the network and all links between those devices are used and administratively controlled by a single organization. Prior to the Internet, most large corporate networks were private networks. In a private network, when a network is spread out among multiple geographic locations in a WAN, the organization arranges for one or more telephone-company-provided leased lines, to connect each pair of sites, which will communicate with each other.

The major advantage of private networks is privacy. No one but the companies connected at either end of the leased line can access the data traveling across them, providing a high degree of security in terms of data privacy and ensuring that any users accessing machines on the network are authorized to do so.

The primary downside to private networks is cost. If you need to connect machines in Atlanta and San Francisco, it’s necessary to pay the phone company a tariff-based fee (usually based mostly on distance) for the cross-country leased line. If you add offices in Dallas and Milwaukee, you have to pay more tariff-based fees for thousands of miles of leased lines to add these sites to your private network.

VI  Private vs Public Networks 1 Public Networks