C
HAPTER
32
| UniDirectional Link Detection Commands
– 1055 –
problem. Because this type of detection can be event-less, and lack of
information cannot always be associated to an actual malfunction of the
link, this mode is optional and is recommended only in certain
scenarios (typically only on point-to-point links where no
communication failure between two neighbors is admissible).
EXAMPLE
This example enables UDLD aggressive mode on port 1.
Console(config)#interface ethernet 1/1
Console(config-if)#udld aggressive
Console(config-if)#
udld port This command enables UDLD on an interface. Use the no form to disable
UDLD on an interface.
SYNTAX
[no] udld port
DEFAULT SETTING
Disabled
COMMAND MODE
Interface Configuration (Ethernet Port)
COMMAND USAGE
â—† UDLD requires that all the devices connected to the same LAN segment
be running the protocol in order for a potential mis-configuration to be
detected and for prompt corrective action to be taken.
â—† Whenever a UDLD device learns about a new neighbor or receives a re-
synchronization request from an out-of-synch neighbor, it (re)starts the
detection process on its side of the connection and sends N echo
messages in reply. (This mechanism implicitly assumes that N packets
are sufficient to get through a link and reach the other end, even
though some of them might get dropped during the transmission.)
Since this behavior must be the same on all the neighbors, the sender
of the echoes expects to receive an echo in reply. If the detection
process ends without the proper echo information being received, the
link is considered to be unidirectional.
EXAMPLE
Console(config)#interface ethernet 1/1
Console(config-if)#udld port
Console(config-if)#
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