Unit 5: Fundamentals of Computer Networks

Computer Network

two or more devices that are connected together for the purpose of communication.

PAN stands for…

personal area network

What is a PAN

a network spread over a very small geographical area used to connect personal devices

example of PAN

bluetooth headphones

LAN stands for..

local area network

what does a LAN do

network that connects computers within a limited geographical area

where is LAN used

residence, school, office building

who manages a LAN

One person/organisation

WAN stands for…

wide area network

What does WAN do

network that extends over a large geographic area

Example of WAN

the internet, banks

Who controls a WAN

Under collective or distributed ownership

Router

a device that forwards data packets networks, determines the best path for data

switches

network devices that record which computers are connected to which parts. when traffic is received the switch forwards the traffic to its intended recipient only.

how do switches improve network performance

cuts down on unnecessary transmissions from older style networks

network protocol

a set of rules/procedures that allow devices/networks to communicate

node

any device connected to a network

MAC address

unique serial number assigned to each NIC, each device has a unique address, it never changes

IP address

when a device connects to a network, it is given an IP address, it will change depending on the network it is connected to

Computer network pros

sharing resources, managed backing up of data, central installation and management of software by network admin, communication between devices, monitor users and activity

computer network cons

security, spreading of malware, cost of infrastructure, cost of network admin to run the network

wired network

use of physical wiring to connect devices

when are wired networks used

office networks or for devices that are stationary, cables limit movement

wireless networks

use radio waves to carry signals, up to 50 metre range on average

when are wireless networks used

mobile devices, can connect to network as long as it is in range of WAP

WAP

Wireless access point

Wired network pros

large range 100m-2km, very secure,1GB per second on ethernet

wired network cons

installation costs is expensive, installation requires technical knowledge and space to install cables

wireless networks pros

cheaper to set up, easy connection, installation is simple

wireless networks cons

up to 50MB per second, range of only 50m, less secure

types of cable

copper wire, fibre-optic

stats of copper wire

cheaper cost, up to 10GB a second, up to 100m communication

stats of fibreoptic

more expensive, up to 100GB a second, up to 2km communication

bus topology

all nodes in the network are connected directly to the central cable that runs up and down the network, data is sent along the backbone until it reaches the correct node

bus pros

easy to connect nodes, less cabling is needed, cheaper to installcon

bus cons

if backbone broken the whole network fails, having one backbone increases the chance of data collisionsta

star topology

all nodes indirectly connect to each other through one or more switches, switch acts as a central point where all communication is passed

star pros

each node is connected separately, if one fails it doesn’t affect the others, adding nodes is simple, higher performance as message is passed directly