What are networks?

A network is a number of computers and peripherals linked together so that data can be passed between them. The rise in the popularity of networks has led to a variety of approaches to network construction. To help distinguish between different approaches, engineers categorise
networks according to:
size
the way they are arranged (the topology)
the set of rules they observe when com
municating (the protocols)
the model or architecture of how the
network functions (peer-to-peer or
client/server).
Network Transmission

The commonest forms of data transmission in a network use packets, or frames, of data. A
packet is simply a block of data that originates at one point in the network and is destined for another point. The packets of data are transmitted via the cabling or wireless communication used by the network.
In order to identify the destination of the data packet, an address is attached to it. The address is a unique identifier of the destination point, whether it is a workstation, printer, or other network component. The address attached to the packet ensures that it is directed to the right part of the network, and that only the addressee will receive it. The structure and addressing of packets is determined by the protocols of the network operating system. Overall standards are set by the IEEE (Institute of Electrical and Electronics Engineers). Standard 802.2 defines framing and addressing standards.
LANs and WANs

Generallay networks are divided into to catagories:
1. LANs (Local Area Networks) and
2. WANs (Wide Area Networks).