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Changing the Logical Loopback Interface for Provisioning

The loopback interface supports many different network and operational functions and is an always-up interface. This means that the loopback interface ensures that the device is reachable, even if some of the physical interfaces are down or removed, or an IP address has changed. In most cases, you always define a loopback interface.

Junos OS follows the IP convention of identifying the loopback interface as lo0.

Junos OS requires that the loopback interface always be configured with a /32 network mask, thus avoiding any unnecessary allocation of address space.

Typically, the VRF or virtual-router routing instance IP address is drawn from among the IP addresses associated with interfaces configured for that routing instance. If none of the interfaces associated with a VRF or virtual-router routing instance is configured with an IP address, you need to explicitly configure a logical loopback interface with an IP address. This interface must then be associated with the routing instance.

You change the logical unit of the loopback interface to be a logical unit other than unit 0 to be used as the default loopback logical interface for all provisioning tasks that are initiated from Connectivity Services Director

Note:

Although Junos OS allows you to assign multiple loopback addresses to the same loopback unit, the Junos Space software recognizes only the first address assigned to the loopback unit. Therefore, when you change the loopback address of an N-PE device, it must be to that of a different loopback unit.

To change the logical unit of the loopback interface:

  1. From the Junos Space user interface, click the System icon on the Connectivity Services Director banner.

    The options that you can configure in System mode are displayed in a drop-down menu.

  2. Select Preferences from the drop-down menu to open the Preferences page.

    The Preferences page opens with User Preferences as the default tab.

  3. Click the Services Activation tab to configure the services activation-related settings.

    The settings that you can configure on the Services Activation tab are displayed.

  4. Click the right arrow beside the Prestage Device section to expand it.

    The parameters that you can configure for prestaging devices are displayed.

  5. In the Loopback Unit field, specify the logical unit of the loopback interface that must be used as the default loopback logical interface for all provisioning tasks that are initiated from Connectivity Services Director. The default logical unit for the loopback interface is 0.
  6. Click OK to save the settings. You are prompted to confirm the changes you made to services-activation preferences.
  7. Click Yes to confirm. The Preferences page is closed. A dialog box is displayed to confirm the successful saving of the preferences. Click OK to close the dialog box.

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