Starting an LU-LU Session from a PLU

The PLU program can start unsolicited LU-LU sessions. The PLU starts sessions by generating a BIND command. A subsequent positive response establishes the agreement to communicate. A data field that is associated with the BIND command contains the name of the PLU application program and the session BIND parameters. For more information about the format of this data field, refer to Systems Network Architecture: Formats.

For nonnegotiable BINDs, the SLU returns a positive response if the parameters are acceptable. If the parameters are unacceptable, the SLU returns a negative response with sense data to the PLU.

The negotiable BIND command permits the SLU to return a positive response with a minimum of 26 bytes of updated session parameters indicating compatibility with the PLU parameters. If the PLU finds the returned parameters acceptable, it sends a Start Data Traffic (SDT) command. If the returned parameters are unacceptable, the PLU sends an UNBIND command that indicates unacceptable negotiable BIND command parameters from the SLU.