Operation Manual – DLDPH3C S7500 Series Ethernet Switches Chapter 1 DLDP Configuration1-1Chapter 1 DLDP ConfigurationWhen configuring Device Link Detection Protocol (DLDP), go to these sections forinformation you are interested in:z Overviewz DLDP Fundamentalsz DLDP Configurationz DLDP Network Example1.1 Overview1.1.1 IntroductionYou may have encountered unidirectional links in networking. When a unidirectionallink occurs, the local device can receive packets from the peer device through the linklayer, but the peer device cannot receive packets from the local device. Unidirectionallink can cause problems such as Spanning Tree Protocol (STP) loops.Unidirectional links can be caused byz Fiber cross-connection, as shown in Figure 1-1z Fibers that are not connected or disconnected, as shown in Figure 1-2, the hollowlines in which refer to fibers that are not connected or disconnected.DLDP can detect the link status of an optical fiber cable or copper twisted pair (such assuper category 5 twisted pair). If DLDP finds a unidirectional link, it disables the relatedport automatically or prompts you to disable it manually according to the configurations,to avoid network problems.SwitchBSwitchAPCGE2/0/3GE2/0/3 GE2/0/4GE2/0/4SwitchBSwitchAPCGE2/0/3GE2/0/3 GE2/0/4GE2/0/4Figure 1-1 Fiber cross-connection
