3com S7906E Installation Instruction

 

1-2 

Figure 1-1 Two nested MDs 

 

 

 

CFD exchanges messages and performs operations on a per-domain basis. By planning MDs properly 

in a network, you can use CFD to locate failure points rapidly.  

A maintenance association (MA) is a set of maintenance points (MPs) in an MD. An MA is identified by 

the “MD name + MA name”. 

An MA serves a VLAN. Packets sent by the MPs in an MA carry the corresponding VLAN tag. An MP 

can receive packets sent by other MPs in the same MA. 

An MP is configured on a port and belongs to an MA. MPs fall into two types: maintenance association 

end points (MEPs) and maintenance association intermediate points (MIPs). 

z 

MEP 

Each MEP is identified by an integer called a MEP ID. The MEPs of an MD define the range and 

boundary of the MD. The MA and MD that a MEP belongs to define the VLAN attribute and level of the 

packets sent by the MEP. MEPs fall into inward-facing MEPs and outward-facing MEPs. 

The level of a MEP determines the levels of packets that the MEP can process. The packets transmitted 

from a MEP carry the level of the MEP. A MEP forwards packets at a higher level and processes packet 

of its level or lower. The processing procedure is specific to packets in the same VLAN. Packets of 

different VLANs are independent.  

The direction of a MEP determines the position of the MD relative to the port. In 

outward-facing MEPs are configured on the two ports. In 

, inward-facing MEPs are 

configured on the two ports. 

An outward-facing MEP communicates through the wire side connected to the port; an inward-facing 

MEP communicates through the relay function side.