3.3 Networks

Two or more computers connected together so that they can transmit data between each other.

local area network LAN wide area network WAN

hardware is privately owned small geographic area MAC addresses used to communicate between LAN devices

makes use of external or third party hardware large geographic area connects to other networks IP addresses are used for routers to connect networks together

The physical topology is the layout of the wires or the way in which components are connected whereas logical is about how the data flows and is transmitted.

bus star mesh

A layout where all terminals/devices are connected to a backbone cable. The ends of the cable are plugged into a terminator.

cheap to set up doesn’t require additional hardware

entire network disconnects if the backbone cable fails all computers have access to the data transmission heavy traffic reduces performance and is all transmitted through one cable

A layout where all devices are connected to a central node which is typically a switch. MAC addresses are used to uniquely identify each device on the network.

media access control

A physical device that receives and forwards data packets between computers/network devices on a LAN to connect them. Recipient’s MAC address is stored in packet headers.

if one cable fails, only that device is affected transmits data faster than a bus topology easy to add new devices no data collisions

more expensive than a bus topology if the central switch fails, the entire network disconnects

A network layout where any node can be connected to any other node. A full mesh is where every node is connected to every other node, otherwise its a partial mesh.

as the number of nodes increases, the speed and reliability of data transmission improves no single point of failure

if wired, lots of cables which is expensive if wireless, data transmission may be slower or less reliable network maintenance is difficult and expensive difficult to add new nodes

A set of rules that governs the transmission of data and communication across a network.

So that devices know how to communicate between each other despite having different hardware/software architectures.

hypertext transfer protocol (secure) - used for web pages

transmission control protocol/internet protocol - used for forwarding packets through networks

post office protocol - used for downloading email

internet message access protocol - used for accessing emails on a web server

file transfer protocol - used for transmission of files through networks