OSI MODEL Flashcards
layer 1
physical- what types of cables used, ethernet, wireless
layer 2
data link- mac adresses on this layer and switches found here
layer 3
network- ip adresses on this layer- routers found here
layer 4
transport- broken down into small packets and reassembles them using sequenced numbers-
layer 5
session- the actual connection between two systems and defines what is taking place
layer 6
presentation- converts data into a format the application can read
layer 7
application- smarts (clever code) in the applications that make them network aware
why was the OSI model created
so theres always reliable communication which can cope with stack differences and allow improvement of those stacks
the tcp/ip stack
application, transport, internet, network interface
OSI model and incoming data (how does is work)
client asks web server, Ethernet frame goes through physical (cables,hubs), Ethernet frame then goes up to data link layer where the mac adresses are stripped and senders Mac adress is kept, which leaves the IP packet. iP packet goes up to network layer where the IP adreresses are stripped leaving a TCP segment. IP adress of sender is kept. tCP segment goes up to transport layer where the data is assembled back together using sequenced numbers and sends message acknowlegement. the prts are stripped as is the sequenced number. the senders port is kept. the data goes up to session, presentation and application where it gets ingested by the application smarts of the application running on the destination port.
layer 1 TCP/IP stack
Network interface- physical and data link of the OSI model
layer 2 TCP/IP stack
internet- network layer of the OSI model
layer 3 TCP/IP stack
Transport- Transport layer of the OSI model
layer 4 of the TCP/IP stack
Application- session, presentation and application layer of the OSI model
