H3C Technologies H3C S10500 Series Switches - Manual (Page 29)

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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. CCM frames are multicast
frames.
Loopback
Similar to ping at the IP layer, loopback verifies the connectivity between a local device and a remote
device. To implement this function, the local MEP sends loopback messages (LBMs) to the remote MEP.
Depending on whether the local MEP can receive a loopback reply message (LBR) from the remote MEP,
the link state between the two can be verified. LBM frames and LBR frames are unicast frames.
Linktrace
Linktrace 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 properly, 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 for 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 for 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
Enabling CFD Required
Configuring the CFD protocol version Optional
Creating a service instance with
the MD name
Configuring service
instances
Creating a service instance
without the MD name
Required
Perform either task
Configuring MEPs Required
Configuring basic
CFD settings
Configuring MIP generation rules Required
Configuring CFD Configuring CC on MEPs Required