H3C Technologies H3C S12500 Series Switches - Manual (Page 65)

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The output shows that the link status of both Gigabitethernet 2/0/1 and Gigabitethernet 2/0/2 is
down.
Assume that in this example, the unidirectional links are caused by cross-connected fibers. Correct
the fiber connections, and then bring up the ports shut down earlier.
# On Device A, bring up Gigabitethernet 2/0/1 and Gigabitethernet 2/0/2:
[DeviceA-Gigabitethernet2/0/2] undo shutdown
[DeviceA-Gigabitethernet2/0/2]
%Jan 18 18:22:11:698 2010 DeviceA IFNET/3/LINK_UPDOWN: Gigabitethernet2/0/2 link
status is UP.
[DeviceA-Gigabitethernet2/0/2] quit
[DeviceA] interface gigabitethernet 2/0/1
[DeviceA-Gigabitethernet2/0/1] undo shutdown
[DeviceA-Gigabitethernet2/0/1]
%Jan 18 18:22:46:065 2010 DeviceA IFNET/3/LINK_UPDOWN: Gigabitethernet2/0/1 link
status is UP.
The output indicates that the link status of both Gigabitethernet 2/0/1 and Gigabitethernet 2/0/2
is now up.
Troubleshooting
Symptom
Two DLDP-enabled switches, Switch A and Switch B, are connected through two fiber pairs, in which two
fibers are cross-connected. The unidirectional links cannot be detected. All the four ports involved are in
Advertisement state.
Analysis
The problem can be caused by the following.
• The intervals for sending Advertisement packets on Switch A and Switch B are not the same.
• DLDP authentication modes/passwords on Switch A and Switch B are not the same.
Solution
Make sure the interval to send Advertisement packets, the authentication mode, and the password
configured on Switch A and Switch B are the same.