The session layer defines how to start, control and end conversations (called sessions) between applications. This includes the control and management of multiple bi-directional messages using dialogue control. It also synchronizes dialogue between two hosts' presentation layers and manages their data exchange. The session layer offers provisions for efficient data transfer.

Functions of Session Layer are:

1. Creating a connection – session/communication session between an APPLICATION in one computer and another APPLICATION in another computer

2. Managing multiple sessions

   i. A computer can establish multiple sessions with several other computers

   ii. Two computers can also establish multiple sessions

3. Ending a session

4. The session layer is responsible for dialog control and synchronization.