CAC polls a global resource monitor so that IKE knows when the router is running short of CPU cycles or memory buffers. You
can configure a limit, in the range 1 to 100000, that represents the level of system resource usage in system resource usage
units. When that level of resources is being used, IKE drops (will not accept new) SA requests. To configure the system resource
usage limit, enter the call admission limit command.
For each incoming new SA request, the current load on the router is converted into a numerical value, representing the system
resource usage level, and is compared to the resource limit set by the call admission limit command. If the current load is more than the configured resource limit, IKE drops the new SA request. Load on the router
includes active SAs, CPU usage, and SA requests being considered.
The call admission load command configures a multiplier value from 0 to 1000 that represents a scaling factor for current system resource usage and
a load metric poll rate of 1 to 32 seconds. The numerical value for the system resource usage level is calculated by the formula
(scaling factor * current system resource usage) / 100. It is recommended that the call admission load command not be used unless advised by a Cisco Technical Assistance Center (TAC) engineer.