networks Flashcards
what is a network
2 + computers connected together that can transmit data
what are the 2 types of networks
local area networks
wide area networks
what is a protocol
a set of rules defining hoow 2 computers communicate
they are standard
what are the 6 types of protocols
HTTP
TCP / IP
POP3 IMAP
FTP
what is HTTP (HyperText Transfer Protocol)
used for web page rendering
what is TCP (Transmission Control Protocol) and IP (Internet Protocol)
networking protocol used in the routing of packets through a network
what is POP3 (Post Office Protocol) and IMAP (Internet Message Access Protocol)
mailing protocols used for email access
what is FTP (File Transmission Protocol)
used for the transmission of files over networks
what is the order of the TCP/IP stack
application layer
transport layer
network layer
link layer
what does the application layer do
its based at the top of the stack
it specifies what protocol needs to be used to relate to the application that is being sent
what does the transport layer do
uses TCP to establish end - end connection between source and recipients computer
split data into packets label w packet number, how many packets the og data was split into and the port number being used for communication
if any packet gets lost the transport layer requests retransmissions
what does the network layer do
adds the source and destination IP addresses
routers operate on the network layer and uses IP addresses to forward packets
sockets are used to specify which device the packets are sent to and the application being used on that device
what does the link layer do
connection betweek the network devices
adds mac adress identifying the network interface cards of the source and destination computers for devices on same network
destination MAC address is the same of the recipients computer otherwise it would be of the router
what happens when the destination has been reached of the tcp
mac address is removed by link layer
ip addresses are removed by network layer
transport layers remove port numbers and reassemble the packets
application layer presents data into the form it was requested in
what is the DNS
the domain name system is used to name and organise internet resources
what are packets
segments of data
what information does the header packet contain
sender and recipients IP addresses
protocol being used
order of the packets
time toe live / hop limit (tells the packet when to expire)
what information does the payload packet contain
raw data to be transmitted
what information does the trailer packet contain
checksum or cyclic redundancy check
a code that detecs whether any errors occured during transmission
what is packet switching
communiccation method where data is sent in the most efficient route which can vary
packet switching advantages
multiple methods to ensure data arrives intact
multiple routess can be used so if 1 path breaks
packets can be transferred over very large networks to allow global communication
packet switching disadvantages
time is spent deconstructing and reconstructing data packets
must wait for all packets to arrive before data is recieved
what is circuit switching
method of communication direct link is created betweek 2 devices
maintained for entire conversation
requires devices to transfer and recieve data at the same time
circuit switching advantages
data arrives in logical order - quicker reconstruction
enables 2 users to hold a call without delay in speech
