Layer 5: Session
The session layer manages sessions, which provide maintenance on connections. Mounting a file share via a network requires a number of maintenance sessions, such as remote procedure calls (RPCs), which exist at the session layer. The session layer provides connections between applications and uses simplex, half-duplex, and fullduplex communication.
*For Certification Exams*
The transport and session layers are often confused. For example, is “maintenance of connections” a transport layer or session layer issue? Packets are sequenced at the transport layer, and network file shares can be remounted at the session layer; you may consider either to be maintenance. Words like “maintenance” imply more work than packet sequencing or retransmission; it requires “heavier lifting,” like remounting a network share that has been unmounted, so session layer is the best answer.