1.4- Wired & Wireless Networks
Networks (general)
A network is 2 or more electronic devices connected through a wired or wireless medium
Computers not connected to a network are called stand alone computers
Types of Networks
LAN- Local Area Network
WAN- Wide Area Network
Factors which affect network performance
Client-server network
Peer-to-peer network
Hardware to connect a computer to a LAN
Virtual Networks
The Internet as a worldwide collection of computer networks
Advantages of Networks
file and hardware sharing between users
communication via email, video.etc
roaming access- sign in & access from any device on network
centralized security, maintenance & updates
Disadvantages of Networks
additional cost of equipment (expensive)
requires management by technical staff
malware spreads easily if poorly secured
if server fails, all devices connected may fail too
computers may work slower due to data traffic
A network spread over a geographically small area
Set up using UTP cable, fiber optic cable or Wi-Fi- all owned & managed by owners
E.g. schools, small businesses, homes
A network spread over a geographically large area, connecting multiple LANs
Connected via telephone lines, satellite links or fiber optic cable- may leased from telecommunication companies
E.g. connecting 2 university campuses, the Internet
Number of users- Too many users slows network
Error Rate- higher error rate reduces performance
Transmission Media- wired connections have higher bandwidth than wireless & fiber optic cable has higher bandwidth than copper cable- wired connection via fiber optic cable gives better network performance than copper cable/ wireless
Bandwidth (amount of data successfully sent & received in a given amount of time)- high bandwidth increases performance
Latency (delay in data being sent & received)- higher latency reduces network performance
A server manages everything in the network (storing files, services to clients, access to internet.etc)- they have total control & allow other devices to communicate
A client is a device which relies on the server for everything (e.g. providing & managing data)- they make requests to the server for data, services and connections
Advantages
easier to take data backups
easier to install software updates
easier to manage file security
Disadvantages
requires IT specialists for maintenance
if server fails, whole system fails
expensive to set up & maintain
There are no clients or servers, all devices are peers- no device has total control and every device is equal
Advantages
not dependent on a single machine
no specialist staff needed- easy to maintain
cheaper to set up than client-server
Disadvantages
users need to do their own backups
less secure
difficult to maintain a well-ordered file store
Network Interface Controller (NIC)- connects device to a wired/wireless network, uses protocols to ensure successful communication
Wireless Access Point (WAP)- allows devices to connect wirelessly to the network, becoming more preferred than wired connections but has lower bandwidth and is less secure
Switch- sends data between devices connected on a LAN, using NIC address to direct data
Router- sends data between devices on a network by using their IP addresses to direct it
Transmission Media
Fibre Optic- used for longer distances and WANs, has a higher bandwidth and less interference
Copper Cable (UTP)-used for shorter connections (e.g. computers to a switch), cheap, flexible & easy to install
The internet is a global connection of interconnected networks
Web addresses are converted into IP addresses for routers by a domain name server (DNS)
Provides 24/7 access, multiple users and greater security
Cloud storage
Hosting- servers store data & programs remotely that can be accessed & used on the internet
Advantages:provides collaboration on documents, automatic backup and access to files anytime & anywhere
A virtual network is a network which applies the logic of networking without the same physical layout
Disadvantages: risk of hacking, requires trust in the host, web server failure= no data access
Software is used to set user access details so they can only access files which they're permitted to do so
Advantages: easily scalable, no network infrastructure needed (cheap), secure (VLANs can't be accessed by other people who use other VLANs even if they're connected to the same switch)