Session Layer 5

The Session layer defines how data conversations are started, controlled and finished. The Session layer manages the transaction sequencing and in some cases authorisation. The messages may be bidirectional and there may be many of them, the session layer manages these conversations and creates notifications if some messages fail. Indications show whether a packet is in the middle of a conversation flow or at the end. Only after a completed conversation will the data be passed up to layer 6. Examples of Session layer protocols are listed below:

• RPC
• SQL
• NetBIOS names
• Appletalk ASP
• DECnet SCP