Reference Guide
Dell(conf-if-po-1)#switchport backup interface tengigabitethernet 0/2
Apr 9 00:16:29: %STKUNIT0-M:CP %IFMGR-5-L2BKUP_WARN: Do not run any Layer2 protocols on
Po 1 and Te 0/2
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 specified time interval.
You can enable FEFD globally or locally on an interface basis. Disabling the global FEFD configuration does not disable the
interface configuration.
Figure 67. Configuring 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 specified 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 switchs between four different states: Idle,
Unknown, Bi-directional, and Err-disabled.
1. An interface on which FEFD is not configured is in Normal mode by default.
Layer 2
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