This topic describes the guidelines and limitations to configure IP event dampening, including how penalties accumulate and decay, how the interface transitions between the dampened and unsuppressed states, and the supported interfaces and IP client behavior.
Penalty accumulation and decay
Consider the following behavior for how penalties are assigned and reduced when IP event dampening is enabled on an interface:
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When dampening is enabled, a penalty value is assigned to an interface. This value starts at 0 and increases by 1000 each time the interface state transitions from up to down.
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For each flap of the interface, a certain penalty is added. The penalty decays exponentially when parameters are configured.
Dampening state transitions
Consider the following behavior for how the interface transitions between the dampened and unsuppressed states:
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When the penalty exceeds a certain high level, the interface is dampened. It is unsuppressed when the penalty decays below a low level.
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When an interface is dampened, the IP address and the static routes are removed from the interface. All the clients of IP get an IP delete notification.
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When an interface is unsuppressed, the IP address and the relevant routes are added back. All the clients of IP get an IP address add notification for all the IP addresses of the interface.
Applicability and IP client impact
Consider the following applicability guidelines when configuring IP event dampening:
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All Layer 3 interfaces that are configured on the Ethernet interface, port changes, and SVI support this feature.
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Due to changes in the netstack-IP component, all IP clients observe the impact of interface dampening.