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When the Initiate request is processed by the SSCP, the SSCP notifies the VTAM® application program that the Initiate has been received by sending a Control Initiate (CINIT) request on the SSCP-to-application program LU session. Information derived from the original Initiate that requested the session is transmitted in the CINIT request and includes session parameters and, optionally, a user logon message. The user logon message contains particular user data that the terminal operator or LU that initiated the session wants to be passed to the VTAM application program. Session parameters and the user logon message are available in the CINIT for inspection by the program. Session parameters indicate the communication rules that the initiating LU wants used for the session that is about to be established. Parameters specify whether chained or unchained requests are sent, what kinds of responses are requested, which LU starts and ends brackets, and so on. These session protocols are described in Communicating with logical units.