Network Administration: Port Settings
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FILE LOCATION: C:\Users\gina\Desktop\Checkout_new\Dell Astute\User
Guide\Dell_Astute_Network_Admin_PortSettings.fm
D E L L CO N F I D E N T I A L – P R E L I M I N A RY 8 / 9 / 16 - F O R P RO O F O N L Y
UDLD is enabled on a port when one of the following occurs:
• The port is a fiber port and UDLD is enabled globally.
• The port is a copper port and you specifically enable UDLD on it.
How UDLD Works
When UDLD is enabled on a port, the following actions are performed:
• UDLD initiates the detection state on the port.
In this state, UDLD periodically sends messages on every active interface
to all neighbors. These messages contain the device ID of all known
neighbors. It sends these messages according to a user-defined message
time.
• UDLD receives UDLD messages from neighboring devices. It caches these
messages until the expiration time (3 times message time) has passed. If a
new message is received before the expiration time, the information in
that message replaces the previous one.
• When the expiration time expires, the device does the following with the
information received:
–
If the neighbor message contains the local device ID
—The link
status of the port is set to bidirectional.
–
If the neighbor message does not contain the local device ID
—The
link status of the port is set to unidirectional, and the port is shut
down.
• If UDLD messages are not received from a neighboring device during the
expiration time frame, the link status of the port is sent to undetermined
and the following occurs:
–
Device is in normal UDLD mode:
A notification is issued.
–
Device is in aggressive UDLD mode.
The port is shut down.
While the interface is in the bidirectional or the undetermined state, the
device periodically sends a message each message time seconds. The above
steps are performed over and over.
A port that was shut down can be reactivated manually in the
page. For more information, see
