Public and Private Networks

When applied to a network,the term public refers to the availability of the service,not to the data transferred.In particular,most public networks provide private communications i.e when a computer sends a message across a public network,only the intended recipient receives the copy.Some public networks permit a group of computers to communicate analogous to a telephone conference hall.However,the public network doesn't use the broadcast technology.That is,the public network doesn't have a broadcast address nor it does forward broadcast packets.

The chief advantage of a private network is that owner has full control over both the technical decisions and policies.In addition to this it also have some disadvantages like a large private network can be expensive to install and maintain.In addition to purchasing the network hardware,a corporation must hire and train a staff to install,manage and operate the network.

On the other hand the chief advantage of a public network are flexibility and the ability to use state of the art networking without maintaining the technical expertise. public network is flexible because an arbitrary subscriber at a arbitrary location can connect to the network at any time.Furthermore,connections between a computer owned by one organization and a computer owned by another can be made broken the same way a public telephone system allows voice connections to be made or broken