Administrator Guide

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 75. 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 a far-end failure is detected on an FEFD-enabled interface:
• If the interface is in normal FEFD mode, no user intervention is required to reset the interface; it automatically resets to an FEFD
operational state.
• If the interface is in aggressive FEFD mode, manual intervention is required to reset the interface.
FEFD-enabled systems consist of one or more interfaces, which automatically switch between four states: Idle, Unknown, Bi-directional,
and Err-disabled.
1. An interface on which FEFD is not configured 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.
3. When the local interface receives the echoed packet from the remote end, the local interface transitions to the Bi-directional state.
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