1.3 Flashcards
Internet
Largest most well known WAN
collection of interconnected networks spanning the world
LAN
Local area network
Covers small geographical area
Used in homes
WAN
Wide area network
Covers large geographical area
Contains hardware owned by a third party
The internet
Pros of networks
Allows communication, file transfer and sharing peripherals
Cons of networks
Security risks
Hackers/data theft
Expensive
Network
Group of electronic devices that are interconnected to exchange data and share resources
What is network performance affected by
Bandwidth, latency, transmission media and error rate
What are the two types of transmission media and examples
Wireless- Bluetooth, Wi-Fi
Wired- Ethernet, fibre optic
Pros of client server
Central backup
Better security and maintenance
Cons of client server
More expensive - hardware costs and requires more technical skill
Central point of failure
Pros of peer to peer
No central point of failure
Cheaper - no hardware costs and requires less technical skill
Computers have same level of responsibility
Cons of peer to peer
No central backup
Less security and maintenance
Network interface card
Needed by every device to connect to a network
Switch
Sends data packets within a LAN
Router
Sends data packets between other networks
Wireless access point
Allows device to connect without wires
The cloud
Servers used to store data and programs to be accessed over the internet
Cloud advantages
Accessibility- anywhere anytime
No hardware required as everything is hosted in the cloud
Protocol
Set of rules for how devices communicate and data is transmitted
HTTP
Hyper text transfer protocol
Transferring web pages
Https
Hyper text transfer protocol
Adding encryption to transferring web pages
FTP
File transfer protocol
Transferring files
Pop3
Post office protocol version 3
Receiving emails, original deleted from mail server
IMAP
Internet message access protocol
Receiving emails, original kept on mail server
SMTP
Simple mail transfer protocol
Sending emails
TCP
Sets rules for how devices connect to network
Transmission Control Protocol
Ip
Internet protocol
Directs packets to destination
Layers
Group of protocols with similar functions
Each layer does work to activate the ones beside it
4) turns data into websites and other applications (HTTP,FTP,SMTP)
3) splits data into packets and checks it’s sent and delivered (TCP)
2) makes connections between networks and directs data (IP)
1) passes data over the physical network (Ethernet)
Layers advantages
Breaks network communication into manageable layers
Each layer can be changed without affecting the others
Network topology
Arrangement of all the elements required to build a network
Star topology
Wired with central switch to connect all devices
Pros - if a single cable breaks only that computer is affected
Cons - switch is a single point of failure
Full mesh topology
Every device connected to every other device
Pros - if only one connection is broken it can be sent via a different route
Cons - more cabling and switch hardware required which adds to cost
Web server
Carry out many functions
Most common ones are hosting websites and dealing with client requests
Web server and DNS process
1) website is hosted by web server and has an IP address
2) browser sends URL to domain name service
3) URL has a linked IP and the DNS finds the IP
4) if DNS can’t find the IP it passes a request
