IPL Access Control Algorithm is implemented in linsec_check_ipl function (kernel/linsec_access_control.c) as specified in Chapter 4 (Subsection 4.4.8). The algorithm is triggered by the same set of events that cause SAC (Subsection 5.10.2) algorithm to execute. A call to linsec_check_ipl is, however, placed before a call to SAC algorithm, in the affected network subsystem functions, to avoid the costly invocation of the SAC algorithm if much faster IPL algorithm fails the service request.