3.5 Computer Networks Flashcards
What is a computer network?
Two or more computers connected together
Advantages of computer netoworks 4x
- share files
- share internet connection and hardware devices
- improved communication
- roaming profile
- central backup
Disadvantages of computer networks 4x
- reliance on networked sources
- expensive hardware
- risk of spread of viruses
- specialist staff often required (maintenance & installation)
What is PAN + examples
Personal Area Network
Connect electronic devices within a user’s immediate area
Wired or wireless
Mouse, keyboard, printer, headphones
LAN
Local Area Network
Network contained within one building or site
WAN
Wide Area Network
Computer network that extends over a large geographical area, connecting LANs
LAN topologies
Star & bus
Router
A network device that forwards data packets between computer networks
Gateway
A device used to connect two different networks, especially a connection to the internet
Internet
A global computer network of interconnected networks using standard communication protocols
Broadband
A high speed internet connection
Firewall
A network security system designed to prevent unauthorised access to or from a private network
Define network protocol
A set of rules that allow devices and computer networks to communicate securely and transfer data reliably
Ethernet network protocol
Data transmitted via wired LAN
Copper cable vs fibre optic cable
F.O is faster using protons rather than electrons
Plus not a fire hazard
Wi-Fi
=group of wireless network protocols
Using radio signals
WAP
Wireless access point
Enables mobile devices to have wireless access to wired network
TCP/UDP/IP
IP is an identifier of data
TCP/IP tgt to connect devices
UDP/IP tgt to route and transport data
TCP VS UDP
TCP connect devices and labels packets
UDP sends packets
FTP
file transfer protocol
Legacy communication to transfer files to another computer
Email protocols
Both transfer electronic messages
SMTP: from client to servers or between servers
IMAP: only from an email server to client
4 layer TCP/IP model
Application
Transport
Internet
Link
differences between LAN and WAN
- LAN links only in one site
- speed of LAN transmission is higher than WAN with traffic
- WAN are typically public networks, LANs private, hence no need encryption
define network protocol
a set of rules that allow computer networks to communicate securely and transfer data reliably
what protocols are in application layer?
http https
smtp imap
what protocols are in transport layer?
tcp udp
what protocols are in the internet layer?
ip
what protocols are in link layer?
ethernet, WiFi
network security measures
authentication
encryption
firewalls
mac address filtering
advantages of using wireless networks as opposed to wired networks
-lower setup costs
-no wires/cables required
-easy to connect new devices
-can connect multiple devices without need for extra hardware
advantages of using wired networks as opposed to wireless networks
-connection speeds usually faster
-typically have higher bandwidth
-fewer security risks
disadvantages of using wireless networks as opposed to wired networks
-slower connection
-connection not as stable
-more security risks
disadvantages of using wired networks as opposed to wired networks
-cables are hazardous and unaesthetic
-expensive to set up
-not all devices can connect via cables eg tablets
how does authentication work?
takes one or more data specific to user
and compare to stored credentials to compare if valid
how does mac address filtering work?
takes unique MAC address for a device, and check if its in the whitelist and allow connection to network
advantages of using a star topology instead of bus
- better security
- a faulty connection only disables one computer
why is HTTPS often used rather than HTTP?
S is secure
can only be read by intended recipient
what is encryption?
changing data so they cannot be read (except for those with decryption key)
to prevent unauthorised people from reading sensitive data
