Using 802.1ag MAC Ping to Monitor Link Connectivity on a Layer 2 Network

802.1ag MAC ping monitors connectivity between MEPs or between MEPs and MIPs within an MA.

Context

Similar to the ping operation, 802.1ag MAC ping checks whether the destination device is reachable by sending test packets and receiving response packets. In addition, the ping operation time can be calculated at the transmit end for network performance analysis.

Before performing 802.1ag MAC ping, ensure that 802.1ag has been configured. For more information, see Configuring Basic Ethernet CFM Functions.

Procedure

A device is usually configured with multiple MDs and MAs. To monitor the connectivity of a link between two or more devices, perform either of the following steps on the router with a MEP on one end of the link to be monitored.
- In the MA view:
  1. Run system-view
    
    The system view is displayed.
  2. Run cfm enable
    CFM is globally enabled on the device.
  3. Run cfm md md-name
    
    The MD view is displayed.
  4. Run ma ma-name
    
    The MA view is displayed.
  5. Run ping mac-8021ag mep mep-id mep-id [ md md-name ma ma-name ] { mac mac-address | remote-mep mep-id mep-id } [ -c count | -s packetsize | -t timeout | -p priority-value ] ^*
    
    The connectivity between a MEP and an RMEP or between a MEP and a MIP on other devices is monitored.
    
    The following shows an example:
```
<HUAWEI> system-view 
[~HUAWEI] cfm enable
[*HUAWEI] cfm md md1 
[*HUAWEI-md-md1] ma ma1 
[*HUAWEI-md-md1-ma-ma1] ping mac-8021ag mep mep-id 1 md md1 ma ma1 remote-mep mep-id 2 
Pinging 00e0-fc12-3456 with 95 bytes of data: 
Reply from 00e0-fc12-3456: bytes = 95, time = 11ms 
Reply from 00e0-fc12-3456: bytes = 95, time = 2ms 
Reply from 00e0-fc12-3456: bytes = 95, time = 3ms 
Reply from 00e0-fc12-3456: bytes = 95, time = 3ms 
Reply from 00e0-fc12-3456: bytes = 95, time = 2ms 
Packets: Sent = 5, Received = 5, Lost = 0 (0% loss) 
Minimum = 2ms, Maximum = 11ms, Average = 4ms
```
- In all views except the MA view:
  
  Run ping mac-8021ag mep mep-id mep-id md md-name ma ma-name { mac mac-address | remote-mep mep-id mep-id } [ -c count | -s packetsize | -t timeout | -p priority-value ] ^*
  
  The connectivity between a MEP and an RMEP or between a MEP and a MIP on other devices is monitored.
When implementing 802.1ag MAC ping, ensure that:
- The MEP is configured in the MA.
- If the outbound interface is specified, no inward-facing MEP is configured on it. The interface must be added to the VLAN associated with the MA.
- If the destination node is a MEP, either mac mac-address or remote-mep mep-id mep-id can be selected. If remote-mep mep-id mep-id is selected, the remote maintenance association end point (RMEP) must already be created using the remote-mep command.
- If the destination node is a MIP, select mac mac-address.
The intermediate device on the link to be tested only forwards LBMs and LBRs. Therefore, the MD, MA, or MEP does not need to be configured on the intermediate device.
(Optional) Run display cfm statistics lblt
802.1ag protocol packet statistics are displayed.

If the test using the ping mac-8021ag command fails, you can run this command to check whether a link fault or a device fault occurs.
(Optional) Run reset cfm statistics lblt
The 802.1ag protocol packet statistics are cleared.