CS - slr4/5

cybersecurity, networks

benefits of networks

share files, access files, share peripherals, control security, communicate

drawbacks of networks

security risk, malware/viruses spread easily, if server fails all computers may not work, increased traffic results in slower speeds

LAN / local area network

covers a small geographical area, all hardware owned by the organization using it, wired with utp/fiber optics or wireless

WAN / wide area network

covers a large geographical area, managed and owned by telecommunication companies, connected by telephone lines / fibre optic cables / satellite links

IP address

a unique address that identifies a device on the internet or local network. IPV4 uses 32 bits and IPV6 uses 128 bits

router

forwards data packets from one network to another

packet header

sender IP, receiver IP, sequence number, total number of packets, checksum

packet payload

contains the data being sent in the packet, which can include various types of information depending on the protocol used.

packet footer

end of packet flag

checksum

a value used to verify the integrity of the data in a packet by detecting errors that may have occurred during transmission.

advantages of wired networks

faster transfer speed, more secure, connection is more reliable

disadvantages of wired networks

location is limited, difficult to install, less convenient to share files

advantages of wireless networks

users can access network from anywhere when in range, less complicated to set up, easier to share files

disadvantages of wireless networks

slower transfer speeds, less secure, less reliable

factors that affect network performance

number of users, range, transmission media, bandwidth, latency

bandwidth

the maximum amount of data that can be sent and received in a given time

latency

the delay from transmitting data to receiving it

file transfer time formula

size of file in bits / network speed in bits

1 Mbps

1 million bits per second

1 Gbps

1 billion bits per second

network protocols

HTTP, HTTPS, FTP, IMAP, POP3

http (hypertext transfer protocol)

A protocol used for transferring hypertext requests and information on the internet.

https (hypertext transfer protocol secure)

provides secure communication between devices

FTP

A protocol used for transferring files over the internet.

IMAP

used by email clients to retrieve email from a mail server

smtp

sends mail to a mail server

pop3

used by email clients to retrieve emails from a server

tcp

error free transmission between two routers