Users Guide
Dell(conf-if-po-1)#switchport backup interface gigabitethernet 1/2
Apr 9 00:16:29: %STKUNIT0-M:CP %IFMGR-5-L2BKUP_WARN: Do not run any Layer2 protocols on Po 1
and Gi 1/2
Dell(conf-if-po-1)#
Far-End Failure Detection
Far-end failure detection (FEFD) is a protocol that senses remote data link errors in a network. FEFD responds by sending a unidirectional
report that triggers an echoed response after a specied time interval. You can enable FEFD globally or locally on an interface basis.
Disabling the global FEFD conguration does not disable the interface conguration.
Figure 61. Conguring Far-End Failure Detection
The report consists of several packets in SNAP format that are sent to the nearest known MAC address.
In the event of a far-end failure, the device stops receiving frames and, after the specied time interval, assumes that the far-end is not
available. The connecting line protocol is brought down so that upper layer protocols can detect the neighbor unavailability faster.
FEFD State Changes
FEFD has two operational modes, Normal and Aggressive.
When you enable Normal mode on an interface and a far-end failure is detected, no intervention is required to reset the interface to bring it
back to an FEFD operational state. When you enable Aggressive mode on an interface in the same state, manual intervention is required to
reset the interface.
FEFD enabled systems (comprised of one or more interfaces) automatically switches between four dierent states: Idle, Unknown, Bi-
directional, and Err-disabled.
1 An interface on which FEFD is not congured is in Normal mode by default.
2 After you enable FEFD on an interface, it transitions to the Unknown state and sends an FEFD packet to the remote end of the link.
416
Layer 2