Network Topologies

1. Network Topologies • A network topology describes ways of configuring or laying out a network. • The main topologies: • Star • Bus • Hybrid or tree network

2. Bus Topology Many devices connect to a single cable backbone cable. If the backbone breaks, the entire segment fails – like Christmas tree lights.

3. Bus Topology • relatively cheap and easy to install • don't require much cabling • if too many nodes connect to a single bus, you get network congestion. • Good for small networks.

4. Bus • Advantages – peripherals and computers can be removed at any time with no effect on the network’s capabilities. If a problem occurs with a computer, it has no effect on any other computer. This is a very cheap and easy method. • Disadvantages – having only one backbone cable can lead to down time if the cable has problems, also it too many computers and peripherals are connected to the backbone network congestion is likely to occur.

5. Star Topology • central connection point (e.g. server, switch) with cables branching to many computers. • Simple & easy to manage • If a cable fails, only one node will fail. • If switch fails entire network inoperable • A lot of cabling required

6. Hybrid or Tree Topology Combines bus and star topologies. It looks like a tree. Very common in larger networks. e.g. one cable from a file server leads to a 24 port switch. Many cables branch from this switch to the computers in the computer room. They share the bandwidth of the incoming cable.

7. Intranets • An internal, secure network operating as a LAN, which uses internet and web technologies • Uses a web server to deliver web pages • Benefits: • Communication within organisation, notices, policies, et • Training through publication of, eg, online manuals • Contacts re who to approach for problems • Reduce costs in organisations, as require less paper, less time to find data, reduced queries from employees • Accessing intranet is fast as not going through a modem • Restricted access to company information