FTOS Configuration Guide for the C-Series - Force10 Networks

The SONET ring has its own restore time whenever there is a failure. During this time, however,
the Ethernet interface connected to the switch will flap. Link Debounce Timer instructs the
Ethernet switch to delay the notification of the link change to the upper layers. If the link state
changes again within this period, no notification goes to the upper layers, so that the switch
remains unaware of the change.
Note: Enabling the link debounce timer causes link up and link down detections to be delayed,
resulting in traffic being blackholed during the debouncing period. This situation might affect
the convergence and reconvergence of some Layer 2 and Layer 3 protocols.
Important Points to Remember
• Link Debounce Timer is configurable on physical ports only.
• Only 1G fiber, 10/100/1000 copper, 10G fiber, 10G copper are supported.
• This feature is not supported on management interfaces or SONET interfaces.
• Link Debounce takes effect only when the operational state of the port is up.
• Link Debounce is supported on interfaces that also have link dampening configured.
• Unlike link dampening, link debounce timer does not notify other protocols.
• Changes made do not affect any ongoing debounces. The timer changes take affect from the next
debounce onward.
Assigning a debounce time to an interface
Command Syntax Command Mode Purpose
link debounce time [milliseconds] INTERFACE Enter the time to delay link status change notification
on this interface.
Range: 100-5000 ms
• Default for Copper is 3100 ms
• Default for Fiber is 100 ms
Figure 183 Setting Debounce Time
Force10(conf)#int gi 3/1
Force10(conf-if-gi-3/1)#link debounce time 150
Force10(conf-if-gi-3/1)#
FTOS Configuration Guide, version 7.7.1.0 279