Hardware path PBR versus software path PBR

Traffic to be routed that cannot be handled by the switching ASIC (for example IPv4 packets with IP options), is handled by the switch operating system kernel routing software.

The characteristics of network usage determine the proportion of traffic handled by software path PBR relative to the hardware path. Under normal conditions, software path PBR is likely to range from a fraction of a percent of all traffic to almost none.

Packets with IP options are sent to the hardware ASIC as well as the CPU. Since the software path PBR actions are applied to the packets in the CPU, a default entry is programmed in the hardware to take no action on those packets. This hardware entry count can be seen in diagnostics with the command diag-dump policy basic.