3com S7906E 설치 설명서

 

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Linktrace is responsible for identifying the path between the source MEP and the destination MEP. This 

function is implemented in the following way: the source MEP multicasts linktrace messages (LTMs) to 

the destination MEP. After receiving the messages, the destination MEP and the MIPs that the LTMs 

pass send back linktrace reply messages (LTRs) to the source MEP. Based on the reply messages, the 

source MEP can identify the path to the destination MEP. Note that LTMs are multicast frames while 

LTRs are unicast frames.  

The CFD function is implemented in accordance with IEEE 802.1ag. 

For CFD to work effectively, you should first design the network by performing the following tasks: 

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Grade the MDs in the entire network, and define the boundary of each MD. 

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Assign a name for each MD. Make sure that the same MD has the same name on different devices.  

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Define the MA in each MD according to the VLAN you want to monitor. 

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Assign a name for each MA. Make sure that the same MA in the same MD has the same name on 

different devices. 

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Determine the MEP list of each MA in each MD. Make sue that devices in the same MA maintain 

the same MEP list.  

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At the edges of MD and MA, MPs should be designed at the device port. MEPs can be designed on 

devices or ports that are not at the edges. 

Complete the following tasks to configure CFD: 

Required 

These configurations are the foundation for other 
configuration tasks. 

Required 

Configuring the MEPs to send CCMs to manage 
link connectivity 

Configuring LB on MEPs 

Optional 

Checking link state by testing link connectivity 

Configuring LT on MEPs 

Optional 

Tracing link fault and finding the path between 
the source MEP and target MEP 

 

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Normally, a port blocked by STP cannot receive, send, or respond to CFD messages. However, if it 

is configured as an outward-facing MEP, it can still receive and send CCM messages.  

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Only Ethernet ports support CFD.