Networks Fundamentals

A network is a combination of hardware and software that sends data from one location to another. The hardware consists of the physical equipment that carries signals from one point of the network to another. The software consists of instruction sets that make possible the services that we expect from a network.
When we communicate, we are sharing information. This sharing can be local or remote. Between individuals, local communication usually occurs face to face, while remote communication takes place over distance. The term telecommunication, which includes telephony, telegraphy, and television, means communication at a distance (tele is Greek for "far").
Data communications are the exchange of data between two devices via some form of transmission medium such as a wire cable. The effectiveness of a data communications system depends on four fundamental characteristics:
1. Delivery : the system must deliver data to the correct destination.
2. Accuracy : the system must deliver the data accurately.
3. Timeliness : the system must deliver data in a timely manner.
4. Jitter : it refers to the variation in the packet arrival time.