1. Jesse Oleyar Baker College NET 101

2.  Serves as an interface between user and network  application software

3.  Translates data to a language receiving computer understands

4.  Establishes and maintains sessions  Session: the period between establishment of a connection, transmission of the data, and termination of the connection

5.  Ensures data arrives correctly and in the proper sequence  Divides data into segments  Checksum: mathematical sum based on data

6.  Routes message from sender to receiver  Splits data segments further into packets  Packets: small bits of data  Reroutes packets to avoid network congestion

7.  Supervises message transmission  Calculates checksum to ensure everything is in order and undamaged

8.  Encodes all the packets into a signal that will be recognized by the medium of travel

9.  Entire sequence in reverse  Identifies recipient, converts bits into readable data, removes some error checking and control information, and directs to proper application.