Enabling Udld Globally - Cisco IE-4000 Software Configuration Manual

Configuring UDLD
How to Configure UDLD
If you enable aggressive mode when all the neighbors of a port have aged out either in the advertisement or in the
detection phase, UDLD restarts the link-up sequence to resynchronize with any potentially out-of-sync neighbor. UDLD
shuts down the port if, after the fast train of messages, the link state is still undetermined.
Figure 71 UDLD Detection of a Unidirectional Link
Switch B successfully
receives traffic from
Switch A on this port.
Default UDLD Settings
Feature
UDLD global enable state
UDLD per-port enable state for fiber-optic media
UDLD per-port enable state for twisted-pair (copper) media
UDLD aggressive mode
How to Configure UDLD

Enabling UDLD Globally

Follow these steps to enable UDLD in the aggressive or normal mode and to set the configurable message timer on all
fiber-optic ports on the switch:
Switch A
TX RX
TX RX
Switch B
Default Setting
Globally disabled
Disabled on all Ethernet fiber-optic ports
Disabled on all Ethernet 10/100 and 1000BASE-TX ports
Disabled
505
However, Switch A does not receive traffic
from Switch B on the same port. If UDLD
is in aggressive mode, it detects the
problem and disables the port. If UDLD is
in normal mode, the logical link is
considered undetermined, and UDLD
does not disable the interface.