Short for Open System
Interconnection, OSI is a network model developed by ISO
in 1978 where peer-to-peer communications are
divided into seven layers. Each layer performs a specific task or tasks, and builds upon
the preceding layer until the communications is complete. Below are the purposes of
each of the seven layers.
1 - Physical layer
- responsible for the electrical, mechanical and timing across the link.
2 - Data link layer
(also known as the link layer) - responsible for transmitting data across
a link.
3 - Network layer -
responsible for routing information through the network and allowing
systems to communicate.
4 - Transport layer -
responsible for transferring information between endpoints on the
network and deals with errors such as lost or duplicate packets.
5 - Session layer -
responsible for managing a session between two applications.
6 - Presentation layer
- responsible for the data formatting and display, allowing for
compatibility.
7 - Application layer
- responsible for user interaction. An example of an OSI
application is the FTAM.
