Prerequisites to an SNA Session

An LU-LU session consists of communication between a primary logical unit (PLU) and a secondary logical unit (SLU). The SLU is implemented by the LUA application program. Before data can be transferred between a PLU and an SLU on an LU-LU session, the following events must occur:
  1. Personal Communications and Communications Server activate the data link.
  2. When the data link is ready, the system services control point (SSCP) establishes a session between itself and a physical unit (SSCP-PU session) by sending an Activate Physical Unit (ACTPU) command and reading a positive response from either the Personal Communications or Communications Server program. Then either program sends a positive response if the PU address from the ACTPU command corresponds to the configuration information.
  3. The SSCP establishes a session between itself and the logical unit (SSCP-LU session) by sending an Activate Logical Unit (ACTLU) command and reading a positive response from either the Personal Communications or Communications Server program. Then either program sends a positive response if the LU address from the ACTLU command corresponds to the configuration information.