Users Guide

● In the unknown state, the interface starts transmitting link state information at a regular interval. The interface state
changes to bi-directional when a handshake is complete with the peer.
● When an interface is in bi-directional state, if it does not receive an echo from its peer for the time interval of three times
the configured FEFD message interval, the interface state changes to unknown in Normal mode. In Aggressive mode, the
interface state changes to err-disabled.
If the interface state changes to err-disabled, use the fefd reset [interface] global command to reset these interfaces.
The unknown or err-disabled state brings the line protocol down so that the protocols above it can detect that the peer link is
down.
Table 23. FEFD state changes
Local event
(User
intervention
)
Configured
FEFD mode
Local state
(Show
display)
(Result)
Local admin
State
(Result)
Local line
protocol
Status
(Result)
Remote
state
(Show
display)
(Result)
Remote
admin state
Remote line
protocol
status
Shutdown(us
er
configuration)
Normal Admin
Shutdown
Down Down Line protocol
is down.
Up Down
Shutdown(us
er
configuration)
Aggressive Admin
Shutdown
Down Down Line protocol
is down.
Up Down
FEFD+ FEFD
disable(user
configuration)
Normal Locally
disabled
Up Up Unknown Up Down
FEFD + FEFD
disable(user
configuration)
Aggressive Locally
disabled
Up Down Err-disabled Up Down
Link Failure
(Remove
cable or
transceiver)
Normal Unknown Up Down Unknown Up Down
Link
Failure(Remo
ve cable or
transceiver)
Aggressive Unknown Up Down Unknown Up Down
FEFD
enable(user
configuration)
Normal Bi-directional Up Up Bi-directional Up Up
FEFD
enable(user
configuration)
Aggressive Bi-directional Up Up Bi-directional Up Up
Restrictions
● You can enable FEFD globally or on an interface. If FEFD is enabled globally, the FEFD interface configuration overrides
global FEFD configuration.
● OS10 supports FEFD only on physical interfaces. FEFD is not supported on any other interfaces. However, you can enable
FEFD on individual physical interfaces that belong to a port channel.
Enable FEFD globally
To configure FEFD globally:
Layer 2
449