H3C S7500 Series Ethernet Switches Operation Manual

Operation Manual – DLDP

H3C S7500 Series Ethernet Switches Chapter 1

DLDP Configuration

1-1

Chapter 1 DLDP Configuration

When configuring Device Link Detection Protocol (DLDP), go to these sections for

information you are interested in:

z Overview

z DLDP Fundamentals

z DLDP Configuration

z DLDP Network Example

1.1 Overview

1.1.1 Introduction

You may have encountered unidirectional links in networking. When a unidirectional

link occurs, the local device can receive packets from the peer device through the link

layer, but the peer device cannot receive packets from the local device. Unidirectional

link can cause problems such as Spanning Tree Protocol (STP) loops.

Unidirectional links can be caused by

z Fiber cross-connection, as shown in Figure 1-1

z Fibers that are not connected or disconnected, as shown in Figure 1-2, the hollow

lines 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 as

super category 5 twisted pair). If DLDP finds a unidirectional link, it disables the related

port automatically or prompts you to disable it manually according to the configurations,

to avoid network problems.

SwitchB

SwitchA

GE2/0/3

GE2/0/4

SwitchB

SwitchA

GE2/0/3

GE2/0/4

Figure 1-1 Fiber cross-connection