OSI for CCNA Layer 5: Session
As a certified CCNA, you'll work in communications between applications. Some applications need to open logical communication channels between the computer hosts. Logical communication channels (sessions) maintain data about the communication established between the network application running on the sending host and the network application running on the receiving host. The session layer does the following:
Opens and maintains logical communication channels between network applications running on the sending host and network applications running on the receiving host.
Handles authentication: Some network applications use authentication mechanisms before they open a logical communication channel (session) with a remote host.