Enabling CFM on a CPE device

A CPE device with CFM enabled sends control packets over all of its links, including new links that will be established in the future. You can enable or disable CFM in a CPE template or on a CPE device. CFM settings specified in the CPE template are automatically propagated to all CPE devices that use this CPE template.

When CFM is enabled on one CPE device and disabled on the other CPE device, the CPE device with CFM enabled takes precedence. In this case, CPE devices send control packets to each other over all of their links.

To enable CFM on a CPE device:

  1. Enable CFM on the CPE device in one of the following ways:
    • If you want to enable CFM in a CPE template, go to the SD-WAN → CPE templates menu section, click the CPE template, and select the CFM tab.
    • If you want to enable CFM on a CPE device, go to the SD-WAN → CPE menu section, click the CPE device, select the CFM tab, and select the Override check box.
  2. In the CFM drop-down list, select Enabled. The default value is Disabled.
  3. In the Interval drop-down list, select the time interval for sending control packets:
    • 300 ms.
    • 1 s. Default value.
    • 10 s.
    • 1 min.

    The response timeout is equal to the control packet sending interval times 3.5. The time it takes to switch a CPE device over to a new connection when no response packets are received is equal to the control packet sending interval multiplied by a number in the range from 3.5 to 7. For example, if in the Interval drop-down list, you selected 300 ms, the response timeout is 1.05 seconds, and the time it takes to switch the CPE device to a new link is 1.05 to 2.1 seconds.

    If you specified different control packet intervals on CPE devices, the largest of the specified intervals is used. For example, if in the Interval drop-down list for CPE 1, you selected 300 ms, and for CPE 2 you selected 1 s, the time interval for sending control packets is 1 second.

  4. In the upper part of the settings area, click Save to save the settings of the CPE template or CPE device.
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