Disable Port On One Sfm; Link Dampening; Important Points To Remember - Dell Force10 C150 Configuration Manual

When an E300 system boots up and a single SFM is active this configuration, any ports configured with
this feature will be shut down. All other ports are booted up.
Similarly, if an SFM fails (or is removed) in an E300 system with two SFM, ports configured with this
feature will be shut down. All other ports are treated normally.
When a second SFM is installed or replaced, all ports are booted up and treated as normally. This feature
does not take affect until a single SFM is active in the E300 system.

Disable port on one SFM

This feature must be configured for each interface to shut down in the event that an SFM is disabled. Enter
the command
available.

Link Dampening

Interface state changes occur when interfaces are administratively brought up or down or if an interface
state changes. Every time an interface changes state or flaps, routing protocols are notified of the status of
the routes that are affected by the change in state, and these protocols go through momentous task of
re-converging. Flapping therefore puts the status of entire network at risk of transient loops and black
holes.
Link dampening minimizes the risk created by flapping by imposing a penalty for each interface flap and
decaying the penalty exponentially. Once the penalty exceeds certain threshold, the interface is put in an
"error-disabled" state, and for all practical purposes of routing, the interface is deemed to be "down." Once
the interface becomes stable and the penalty decays below a certain threshold, the interface comes up again
and the routing protocols re-converge.
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
• Link dampening can be applied to Layer 2 and Layer 3 interfaces.
• Link dampening can be configured on individual interfaces in a LAG.
448 | Interfaces
disable-on-sfm-failure
from INTERFACE mode to disable the port when only a single SFM is