Link Debounce Timer; Important Points To Remember About Link Debounce Timer; Assign A Debounce Time To An Interface - Dell Force10 S4810P Configuration Manual

Link Debounce Timer

Link Debounce Timer
The Link Debounce Timer feature isolates upper layer protocols on Ethernet switches and routers from
very short-term, possibly repetitive interface flaps often caused by network jitter on the DWDM equipment
connecting the switch and other devices on a SONET ring. The Link Debounce Timer delays link change
notifications, thus decreasing traffic loss due to network configuration. All interfaces have a built-in timer
to manage traffic. This feature extends the time allowed by the upper layers.
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 about Link Debounce Timer

• 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.

Assign a debounce time to an interface

Command Syntax
link debounce time [milliseconds]
FTOS(conf)#int gi 3/1
FTOS(conf-if-gi-3/1)#link debounce time 150
FTOS(conf-if-gi-3/1)#=
is supported on platform
Command Mode
INTERFACE
e
Purpose
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
Interfaces | 501