Network Control

Network control is the transmission of signaling messages that perform call-control functions such as supervision, call setup routing, provisioning (authorizing) of services, and call processing control. Networks are either common to all users or privately leased by a customer for some specific application. The term “network” also refers to a group of two or more broadcast stations or cable systems interconnected physically and organizationally so as to broadcast the same program schedule simultaneously without any switching functions.

In the early telephone systems, network control routing of a telephone connection was manually monitored and processed by human operators. Human operators would supervise the call by listening for request tones (ringing sounds) and manually coordinate the connection by talking to end customers (who originate calls) and other operators (for cross-connections). When the call setup process had been agreed (all the switching points established), the connection was made through physical connections (patch panels).

To provide for more efficient network control, telephone control signals (tones) were created to allow the transfer or call control information on the same audio lines as the voice signals for call setup. These control tones would either be mixed with the audio or temporarily replace the audio signals. This type of audio signal control is called in-band signaling.

As the design of telephone networks advanced, it was necessary to add more intelligence to the call setup (e.g., automatic forwarding of telephone calls), it became necessary to shift the control signaling to circuits outside the audio path. This allowed more rapid call setup and better overall control over the communications connection. When the control signals are separated from the actual communication channel, these are called out-of-band signaling.

Provisioning of a network is a process within a company that allows for establishment of new accounts, activation and termination of features within these accounts, and coordinating and dispatching the resources necessary to fill those service orders. Provisioning involves customer care and billing systems.

Picture below shows how different types of networks can be controlled. This diagram shows that a network can have no control (distribution only), can use intelligent databases to control dumb switches, or it can use intelligent switches to route information through a dumb network.