Overload Control (OLC) is a mechanism that prevents CPU resources from being exhausted. OLC monitors certain CPU-bound protocol packets and tasks. According to the priorities of different services, OLC rate-limits the monitored protocol packets and tasks if the CPU usage exceeds a certain threshold. In this way, OLC not only reduces consumption of CPU resources but also prevents CPU overload from affecting normal processing of other services.
On a complex live network, the CPU may be overloaded if a large amount of service traffic is sent to the CPU or the CPU is attacked by unauthorized services. CPU overload will affect both the device's performance and its ability to process services.
OLC uses the multi-level leaky bucket algorithm (involving a token bucket and multi-level leaky buckets) to control the CPU-bound monitored protocol packets and tasks. OLC offers the following benefits:
Prevents sustained overloading of the CPU, ensuring availability of device resources.
Prevents devices from being attacked by unauthorized services, ensuring device security.
Prevents certain services from impacting the normal processing of other services, ensuring fairness of service processing.