Telecommunication network can be categorized according to wide geographic that covered. Big city usually have high-density users and heavy traffic per user. Telecommunication network characteristic on big city to consist of lots of local central and one with the other have close distance. Network designed for that condition, usually known as urban network or metropolitan network.
Rural area have characteristic with low density, user that spread everywhere on large area, low traffic per user, just only have one or two central for handling users in wide area, long distance between user and central, bad condition environment and also less to support infrastructure facilities. That area must served by rural network.
Long distance network or Toll functioned as backbone interconnection a metropolitan network and rural network. That networks to support communication intra-country, inter-country, and inter-continent. In the telephone network context, urban network and rural network usually is called local network. But on data network context, local network form usually a network in building or campus.
Right now the gigantic telecommunication network is Public Switched Telephone Network (PSTN) or known as POTS (Plain Old Telephone System). Right now there are more then 500 million telephone in the world and the distance cable for that telephone network is to guess already to reach more than 12 time distance between earth and sun. Speed of growth value exactly already increased. Right now that growth speed has far away from computer industry.
Telecommunication industry and also the services in one country usually government authorized, but development already to show that public sector also can to involve actively. In US almost for the greater part the service provider industry and telecommunication industry is public sector authority. Monopoly by a government usually to covers the pos sectors, telegraph, and telephone. Committee or government department is to authority that sector usually known as post administration, telegraph and telephone (PTT).
With so many agency who involved in to supply telecommunication service, then clearly need a world scale capability guarantee so that between the networks got to be connected each other. This coordination performed by International Telecommunication Union (ITU) is part of United Nation (UN). ITU have 3 main groups, anything such as handling telephone and data communication. This group known as Committee Consultative Internasionale de Telegraphique et Telephonique (CCITT) or International Consultative Committee for Telegraph and Telephones.
