SPDU
SPDU stands for Session Protocol Data Unit. It is a data unit used by the Session Layer in the OSI reference model to manage dialog control between communicating applications. In the ISO/IEC 8328 standard, SPDU messages are exchanged between Session Protocol Entities and carry the control information required to establish, maintain, and terminate a session, as well as to transfer user data in a coordinated manner.
Structure and function: An SPDU typically consists of a header and an optional data field. The header
Typical SPDU types: The messages are categorized by function, including those for connection establishment (setting up
Context and usage: SPDU concepts arise from the OSI model and its Session Layer, and are defined
See also: OSI model, Session Layer, ISO/IEC 8328, SPDU types.