Reference Guide
Interfaces | 621
Parameters
Defaults
Enabled 
Command Modes
INTERFACE
Command
History
Usage
Information
When you configure keepalive, the system sends a self-addressed packet out of the configured 
interface to verify that the far end of a WAN link is up. When you configure 
no keepalive, the 
system does not send keepalive packets and so the local end of a WAN link remains up even if 
the remote end is down.
lfs enable (EtherScale)
e
Enable Link Fault Signaling (LFS) on EtherScale 10 Gigabit Ethernet interfaces only.
Syntax
lfs enable 
To disable LFS, enter 
no lfs enable.
Defaults
Enabled.
Command Modes
INTERFACE (10 Gigabit Ethernet interfaces only)
Command
History
Usage
Information
If there is a failure on the link, FTOS brings down the interface. The interface will stay down 
until the link failure signal stops. 
link debounce-timer
e
Assign the debounce time for link change notification on this interface.
Syntax
link debounce [milliseconds] 
seconds
(OPTIONAL) For SONET interfaces with PPP encapsulation enabled, enter the 
number of seconds between keepalive packets.
Range: 0 to 23767
Default: 10 seconds
Version 8.3.19.0 Introduced on S4820T
Version 8.3.7.0 Introduced on S4810 
Version 8.1.1.2 Introduced on E-Series ExaScale
Version 7.6.1.0 Introduced on S-Series
Version 7.5.1.0 Introduced on C-Series
pre-Version 6.2.1.0 Introduced for E-Series
pre-Version 6.1.1.0 Introduced for E-Series
Note: On TeraScale line cards, LFS is always enabled by default.










