A sessioninitiation request generated when an ACF/VTAM application program issues a SIMLOGON macroinstruction.The request specifies a logical unit (LU) with which the application program wants a session and in which the requesting application program will act as the primary logical unit (PLU).; 当IBM的通信系统软件ACF/VTAM的应用程序发出宏指令SIMLOGON时所产生的一种启动话 路的请求,这个请求指定该应用程序打算与其进行一次通话的一个逻辑单元(LU),在这个 LU中的应用程序将充当主逻辑单元(PLU)。