Starting an LU-LU Session from an SLU

After the SSCP-LU session is established, the SLU program can request an LU-LU session by sending the Initiate Self (INITSELF) command to the SSCP. The SSCP receives the INITSELF command and checks whether the named host application program is valid. A host application program is valid if it is known and active. If the host application program is valid, the SSCP sends a positive response to the SLU, and the PLU starts the session. If the host application program is not valid, the SSCP sends a negative response to the SLU, and the PLU does not start the session.

If the SSCP sends a positive response to an INITSELF command but the session cannot be established, the SSCP sends a Network Services Procedure Error (NSPE) command to the SLU to stop the attempt to establish a session. The SLU can reissue the INITSELF command after the NSPE command.