Introduction What is a Network? Networking Introduction What is a Network?

What is a Network? A network can be defined as a group of computers that share resources. Typically a network is a system of computers that send and receive data and messages enabling two or more computers to communicate with each other and allows the sharing of files, printers and the sending of messages to each other.

Types of Network LAN – Local Area Network A network contained within one building or over several buildings on a site is called a Local Area Network (LAN). MAN – Metropolitan Area Network A network that spans several sites across a city is called a Metropolitan Area Network (MAN) WAN – Wide Area Network A network that spans several cities, country or even the world is called a Wide Area Network (WAN). A Client/Server network may be a LAN, MAN or WAN, however a peer-to-peer network can only be a LAN. The most famous and widely used Wide Area Network is the Internet, which contains many thousands of servers and many millions of clients right across the world.

Network Topologies There are 4 basic types of network topology: - Bus, Star, Ring and Mesh

Bus Topology BUS TOPOLOGY is a specific kind of network topology in which all of the various devices in the network are connected to a single cable or line

In a ring network, every device has exactly two neighbours for communication purposes. All messages travel through a ring in the same direction (effectively either "clockwise" or "counter clockwise"). A failure in any cable or device breaks the loop and can take down the entire network. Ring Topology

With a star topology, the workstations, fileservers, printers etc With a star topology, the workstations, fileservers, printers etc. are attached via cables to a central hub. The hub is central to a star topology and the network cannot function without it. The cables used in star topologies are twisted pair wires. Star topologies are difficult to install, but once installed are easy to maintain and expand. A fault in a cable only affects the computer or node it is attached to and is easy to locate Star Topology

Mesh Mesh topologies involve the concept of routes. Unlike each of the previous topologies, messages sent on a mesh network can take any of several possible paths from source to destination. (Recall that in a ring, although two cable paths exist, messages can only travel in one direction.) Some WANs, like the Internet, employ mesh routing.

Mesh

Conclusion Topologies remain an important part of network design theory. You can probably build a home or small business network without understanding the difference between a bus design and a star design, but understanding the concepts behind these gives you a deeper understanding of important elements like hubs, broadcasts, ports, and routes.