Huawei Quidway S3900 Series Operation Manual page 212

Operation Manual - DLDP
Quidway S3900 Series Ethernet Switches-Release 1510
Note:
When two switches are connected through fibers in a crossed way, two or three ports
may be in the disable state, and the rest in the inactive state.
When a fiber is connected to a device correctly on one end with the other end
connected to no device:
If the device operates in the normal DLDP mode, the end that receives optical
signals is in the advertisement state; the other end is in the inactive state.
If the device operates in the enhance DLDP mode, the end that receives optical
signals is in the disable state; the other end is in the inactive state.
# Restore the ports taken down by DLDP
[QuidwayA] dldp reset
2) Configure Switch B
The configuration of Switch B is the same to that of Switch A.
Note:
For DLDP to detect fiber disconnection in one direction, you must configure the port
to work in mandatory full duplex mode at the mandatory rate.
When the port works in non-mandatory full duplex mode at the non-mandatory rate,
even if DLDP is enabled, it does not take effect when fiber in one direction is
disconnected, in that case, it considers that the port is down.
Huawei Technologies Proprietary
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Chapter 1 DLDP Configuration