D-Link xStack DGS-3610 Series Configuration Manual page 663

DGS-3610 Series Configuration Guide Chapter 47 RLDP Configuration
One-way link detection:
Figure 47-3 One-way link detection
The so-called one-way link detection means the link connected with the port can receive
packet only or send packets only (due to misconnection of the optical receiving line pair, for
example). As shown above, the RLDP only receives the detection packet from the neighbor
port on a port, so it is considered one-way link fault. The RLDP deals with the fault
accordingly according to the user configurations. In addition, if the port cannot receive any
RLDP detection packet, it is also considered one-way link fault.
Two-way link detection:
Figure 47-4 Two-way link detection
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