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Network Administration: Port Settings
FILE LOCATION: C:\Users\gina\Desktop\Checkout_new\Dell Astute\User
Guide\Dell_Astute_Network_Admin_PortSettings.fm
D E L L C O N F ID E N T IA L – P R E L IM I N A R Y 8 / 9 /1 6 - FO R PR O O F O N L Y
If an interface is down and UDLD is enabled, the device removes all neighbor
information and sends at least one ULDL message to the neighbors
informing them that the port is down. When the port is brought up, the
UDLD state is changed to detection.
UDLD Not Supported or is Disabled on a Neighbor
If UDLD is not supported or disabled on a neighbor, then no UDLD
messages are received from that neighbor. In this case, the device cannot
determine whether the link is unidirectional or bidirectional. The status of
the interface is then set to undetermined. The actions taken by the device
depend on whether the UDLD mode is normal or aggressive.
Inconsistent UDLD Mode in Local and Neighboring Device
It is possible for the local device and its neighbor to be set to a different
UDLD mode (normal, aggressive). The UDLD mode is not contained in the
UDLD messages, so that the local device does not know the UDLD mode of
the neighbor and vice versa.
If the UDLD modes are different on the local and neighbor devices, the
devices act as follows:
• When the UDLD state of the link is bidirectional or unidirectional, both
devices shut down their ports.
• When the UDLD state of the port is undetermined, the side with the
normal UDLD mode merely issues a notification, while the side with the
aggressive UDLD mode shuts down the port.
If both devices are in normal mode, the port is not shut down when its state is
undetermined.
Reactivating a Shutdown Port
You can reactivate a port that was shut down by UDLD in one of the
following ways:
•
Automatically
—Configure the system to automatically reactivate ports
shut down by UDLD in the
page. In this case,
when a port is shut down by UDLD, it is automatically reactivated when
the automatic recovery interval expires. UDLD again begins running on
the port. If the link is still unidirectional, UDLD shuts it down again after
the UDLD expiration time expires, for instance.