Types of Networks

WAN vs LAN

 Wide Area Network (WAN) operate over large geographical area. Connects multiple networks together. Relies on third party carriers or connections such as that provided by BT.

Local Area Network (LAN) operates over a small geographical area (one office site or home) and connects devices together via Wifi or network cables. These include PCs, scanners & printers etc.


Topologies

 Physical topology – a network is its actual design layout which is important when you select a wiring system.

Logical topology – shape of the path the data travels in, and describes how components communicate across the physical topology.

Ethernet – uses a logical bus topology when components communicate, regardless of the physical layout.


Bus Topology

LAN can use different topologies. In a bus topology, all computers are connected to a single cable. The ends are plugged into a terminator.

Advantages - Inexpensive to install as it required less cable than a star topology and does not require any additional hardware.

Disadvantages - If main cable fails, network data can no longer be transmitted to any of the nodes, performance degrades with heavy traffic. Also low security – all computers on the network can see all data transmissions.


Star Topology

 Star network has a central node, which may be a switch or computer which acts as a router to transmit messages. Switch keeps a record of the unique MAC address of each device on the network and can identify which particular computer on the network, it should send it to.

Advantages - If one cable fails, only one station is affected, Consistent performance even when the network is being heavily used, higher transmission speeds can give better performance than a bus network, no problem with “collisions” of data since each station has its own cable to the server, more secure as messages are sent directly to the central computer and cannot be intercepted by other stations and easy to add new stations without disrupting the network.

Disadvantages -Costly to install because of the length of cable required, if central device goes down, network data can no longer be transmitted to any of the devices.


Wi-Fi

 Local area wireless technology used to transmit data over a small geographical area (usually no more then 20 metres). Uses Wireless Access Points (WAP) to transmit signals.

Mesh technology is become more and more popular. This is where one devices connects to another to access a signal. That device then extends the signal further. This means only one WAP has to be connected to the internet as the others just connect to that one. Saves costs on cable and is usually faster as data doesn't have to travel via a central switch.

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