R3303-HP HSR6800 Routers High Availability Configuration Guide

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LB
Similar to ping at the IP layer, loopback verifies the connectivity between a source device and a target
device. To implement this function, the source MEP sends loopback messages (LBMs) to the target MEP.
Depending on whether the source MEP can receive a loopback reply message (LBR) from the target MEP,
the link state between the two can be verified. LBM frames and LBR frames are unicast frames.
LT
Linktrace is similar to traceroute. It identifies the path between the source MEP and the target MEP. This
function is implemented in the following way—the source MEP sends the linktrace messages (LTMs) to the
target MEP. After receiving the messages, the target MEP and the MIPs that the LTM frames 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 target MEP. LTM frames are multicast frames and LTRs are unicast frames.
Protocols and standards
IEEE 802.1ag, Virtual Bridged Local Area Networks Amendment 5: Connectivity Fault Management
CFD configuration task list
For CFD to work correctly, design the network by performing the following tasks:
• Grade the MDs in the entire network, and define the boundary of each MD.
• Assign a name to each MD. Make sure that the same MD has the same name on different devices.
• Define the MA in each MD according to the VLAN you want to monitor.
• Assign a name to each MA. Make sure that the same MA in the same MD has the same name on
different devices.
• Determine the MEP list of each MA in each MD. Make sure that devices in the same MA maintain
the same MEP list.
• At the edges of MD and MA, MEPs should be designed at the device port. MIPs can be designed
on devices or ports that are not at the edges.
Complete the following tasks to configure CFD:
Tasks Remarks
Configuring basic CFD
settings
Enabling CFD Required.
Configuring the CFD protocol version Optional.
Configuring MEPs Required.
Configuring MIP generation rules Required.
Configuring CFD
functions
Configuring CC on MEPs Required.
Configuring LB on MEPs Optional.
Configuring LT on MEPs Optional.
Typically, a port blocked by the spanning tree feature cannot receive or send CFD messages except in the
following cases:
• The port is configured as an outward-facing MEP.