Dell PowerSwitch S4820T Configuration Guide for the S4820T System 9.14.1.0 - Page 422
Important Points to Remember, Configuration Example of Link Dampening
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• reuse-threshold- After exponential decay, the penalty reaches the default or configured reuse threshold. The interface is unsuppressed and the state changes to "up". The range of reuse threshold is from 1 to 20000. The default is 750. • max-suppress-time- The maximum amount of time during which the interface remain suppressed. The range is from 1 to 86400. The default is 20 seconds or four times the default half-life period (5 seconds). NOTE: suppress-threshold should be greater than reuse-threshold. max-suppress-time should be at least 4 times half-life. Link dampening: • reduces processing on the CPUs by reducing excessive interface flapping. • improves network stability by penalizing misbehaving interfaces and redirecting traffic. • improves convergence times and stability throughout the network by isolating failures so that disturbances are not propagated. Important Points to Remember • Link dampening is not supported on VLAN interfaces. • Link dampening is disabled when the interface is configured for port monitoring. • You can apply link dampening to Layer 2 and Layer 3 interfaces. • You can configure link dampening on individual interfaces in a LAG. Configuration Example of Link Dampening The figure shows a how link dampening works in a sample scenario when an interface is configured with dampening. The following figure shows the interface state change, accumulation and decay of penalty, and the interface advertised state based on the set dampening parameters. The dampening parameters are set as follows: • half-life- 10 seconds • reuse-threshold-300 • suppress-threshold-2400 • max-suppress-time-60 seconds 422 Interfaces
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