Chapter 6: Session Layer

• Layer 5
• The session layer is responsible for establishing a connection between the two applications, maintain it during the transfer of data, and controlling the release of this connection (Harris, 523).
• The session layer works in three phases:
1. Connection establishment
2. Data transfer
3. Connection release
• The session layer protocol controls application-to-application communication.
• The session layer protocol can enable communication between two applications to happen in three different modes:
• Simplex, communication takes place in one direction.
• Half-duplex, communication takes place in both directions, but only one application can send information at a time.
• Full-duplex, communication takes place in both directions, and both applications can send information at the same time.
• The session layer protocols provide interprocess communications channels, this allows a pice of software on one system to call upon a piece of software on another system without the programmer having to know the specifics of the software on the receiving system.
• They are lease used protocols in a network environment.