OSI And TCP/IP Models Flashcards
OSI Model
provides guidance between networks for communication (framework for new technologies)
model 1st, protocol follows
no protocol definition, protocol independent
connection oriented and connectionless
7 layers
7 layers of OSI model
application > presentation > session > transport > network > data > physical
encapsulation:»_space;
decapsulation: <
layer 7 of OSI
application
host network service
layer 6 of OSI
presentation
sent data is readable, http
layer 5 of OSI
session
establishes, manages, and terminated communication between hosts
layer 4 of OSI
transport
flow contol; segmentation, transfer, and reassembly; ftp, http
layer 3 of OSI
network
connectivity between networks, router
layer 2 of OSI
data
error correction, switch
layer 1 of OSI
physical
physical connection, cables
TCP/IP layers
application > transport > internet > data link
encapsulation:»_space;
decapsulation: <
layer 4 of tcp/ip
application
access app for network communication
layer 3 of tcp/ip
transport
flow control and data error correction
layer 2 of tcp/ip
internet
send packet
layer 1 of tcp/ip
Data link
provides encapsulation
tcp/ip model
made to replace OSI model, less layers (4)
protocol dependent
connectionless
protocol 1st, model 2nd
CSMA/CD
collision detection
used in wired connections listens for quiet line, yes? send data, no? wait rand # ms
collision = back off algorithm used: each collidee picks rand #, 3 chances to to get unique number otherwise you have to wait again for a quiet line
doesn’t prevent collisions
CSMA/CA
collision avoidance
used in wireless connections
listens for idle channel: yes? start transmission, no? back off for rand # ms
Gigabit Network
1999
lack of hub = no collisions
CSMA/CD not required but may be for backwards compatibility
less time to send and receive data
simultaneous conversations
everyone must have gigabit for it to run at max performance
