Symptom
Due to hardware lack of support for general traffic policing and shaping on Nexus 3500 platforms, the "police cir" and "shape kbps" commands are hidden in the "class" sections of a policy-map construct. However, if entered in their entirety, they will still be accepted by the CLI and added to the configuration.
If such a policy-map is applied to an interface, it will obviously have no impact on the actual traffic due to the lack of hardware support, but it will have several disruptive impacts on the behavior of the switch:
1.) It will not be possible to modify the CoPP configuration in any way, either to add a new custom-defined class, or to edit an existing system static class by, for example, changing the PPS rate - these attempts will end with a misleading "ERROR: undefined class". In essence, the switch becomes unable to apply any CoPP settings.
2.) Due to inability to apply CoPP settings during switch bootup, BFD will break: On Nexus 3500 platforms, BFD traffic handling is internally configured as a part of applying CoPP. If the CoPP settings are not successfully applied, the BFD traffic redirection will not be programmed, and BFD sessions will never come up.
3.) In 6.0(2)A8(x) versions, attempting to apply "service-policy type qos input ..." referring to "police cir" to an interface will fail in a subtle way: The interface configuration will not show this command; however, "show accounting log" will state that the command was accepted successfully, and "show queuing interface ..." will actually show this policy-map being applied to the interface.
Conditions
A policy-map type qos is configured for at least one class with "police cir ..." and applied to an interface.
Workaround
Do not attempt to configure "police cir ..." in any policy-map applied to an interface; this is unsupported on the Nexus 3500 platforms. Remove all such commands from policy-maps applied to interfaces.
