4. If the FEFD enabled system is configured to use FEFD in Normal mode and neighboring echoes are
not received after three intervals, (you can set each interval can be set between 3 and 300 seconds)
the state changes to unknown.
5. If the FEFD system has been set to Aggressive mode and neighboring echoes are not received after
three intervals, the state changes to Err-disabled. You must manually reset all interfaces in the Err-
disabled state using the fefd reset [interface] command in EXEC privilege mode (it can be
done globally or one interface at a time) before the FEFD enabled system can become operational
again.
Table 33. State Change When Configuring FEFD
Local
Event Mode Local State Remote
State Local
Admin
Status
Local
Protocol
Status
Remote
Admin
Status
Remote
Protocol
Status
Shutdown Normal Admin
Shutdown
Unknown Down Down Up Down
Shutdown Aggressive Admin
Shutdown
Err-
disabled
Up Down Up Down
FEFD
enable
Normal Bi-
directional
Bi-
directional
Up Up Up Up
FEFD
enable
Aggressive Bi-
directional
Bi-
directional
Up Up Up Up
FEFD +
FEFD
disable
Normal Locally
disabled
Unknown Up Down Up Down
FEFD +
FEFD
disable
Aggressive Locally
disabled
Err-
disabled
Up Down Up Down
Link Failure Normal Unknown Unknown Up Down Up Down
Link Failure Aggressive Err-
disabled
Err-
disabled
Up Down Up Down
Important Points to Remember
• You can enable FEFD globally or on a per-interface basis. Interface FEFD configurations override
global FEFD configurations.
• The system supports FEFD on physical Ethernet interfaces only, excluding the management interface.
Configuring FEFD
You can configure FEFD for all interfaces from CONFIGURATION mode, or on individual interfaces from
INTERFACE mode.
To enable FEFD globally on all interfaces, use the following command.
• Enable FEFD globally on all interfaces.
CONFIGURATION mode
fefd-global
540 Layer 2