Check QoS and control-plane policing

This three-router lab lets us compare traffic to the middle router with traffic through it.

Verify that both destinations reply before applying a policy.

Match echo traffic addressed to the middle router and attach an output policer.

The matching burst loses packets and the interface policy records the excess.

The other destination still replies because it does not match the class.

Increase the permitted burst and repeat the same test.

Remove the output policy before applying a separate control-plane policy on the middle router.

Compare traffic addressed to the router with traffic that only passes through.

Check the control-plane class counters for the locally addressed traffic.