R3102-R3103-HP 6600/HSR6600 Routers High Availability Configuration Guide

configured on the ports of Router A through Router F. Port 1 of Router B is configured with the

following MPs—a level 5 MIP, a level 3 inward-facing MEP, a level 2 inward-facing MEP, and a level

0 outward-facing MEP.

Figure 5 CFD grading example

MEP list

A MEP list is a collection of configurable local MEPs and the remote MEPs to be monitored in the

same MA. It lists all the MEPs configured on different devices in the same MA. The MEPs all have

unique MEP IDs. When a MEP receives from a remote device a continuity check message (CCM) with

a MEP ID not included in the MEP list of the MA, it drops the message.

CFD functions

CFD works effectively only in correctly configured networks. Its functions, which are implemented

through the MPs, include:

 Continuity check (CC)

 Loopback (LB)

 Linktrace (LT)

Connectivity faults are usually caused by device faults or configuration errors. Continuity check

checks the connectivity between MEPs. This function is implemented through periodic sending of

CCMs by the MEPs. A CCM sent by one MEP is intended to be received by all the other MEPs in the

same MA. If a MEP fails to receive the CCMs within 3.5 times the sending interval, the link is

considered faulty and a log is generated. When multiple MEPs send CCMs at the same time, the

multipoint-to-multipoint link check is achieved.

Router A Router B Router C Router D Router E Router F

5 5

3 3

2 2 2 2

0 0 0 0 0 0

MD level 5

MD level 3

MD Level 2 MD Level 2

MD level 0

Port

Outward-facing MEP and MD level

MIP and MD level

Maintenance association

Logical path of CFD messages

Port 1 Port 2

MD level 0 MD level 0

Inward-facing MEP and MD level

2 2 2 2