Automatically Removing VLANs with No Subscribers

You can always clear or delete subscriber VLANs manually. However, you can also configure the interface to automatically remove dynamic subscriber VLANs when no client sessions (for example, DHCP or PPPoE) exist on the VLAN.

When configuring automatic removal of dynamic subscriber VLANs, keep the following in mind:

• You can configure automatic VLAN removal only on individual physical interfaces. You cannot configure the feature globally.

• Automatic VLAN removal is not supported for use on Layer 2 Wholesale interfaces. See Layer 2 and Layer 3 Wholesale Overview.

• PPPoE subscriber interfaces require the use of a dynamic profiles when configured over dynamic VLANS. However, dynamic profiles are not required for use with DHCP subscriber interfaces that use underlying dynamic VLANs. Because the remove-when-no-subscribers functionality triggers when no dynamic client sessions exist on a dynamic VLAN, automatic removal of underlying dynamic VLANs is not supported when DHCP subscriber interfaces are not created using dynamic profiles.

• The maintain-subscriber statement and remove-when-no-subscribers statement are mutually exclusive. When the router is configured to maintain subscribers, you cannot also specify that dynamically configured VLAN interfaces are removed when no subscribers exist.

• If PPPoE subscriber session lockout is also configured, the router does not remove the unused subscriber VLAN until the lockout time has expired for each client undergoing lockout on the underlying interface.

To configure automatic removal of subscriber VLANs when no client sessions exist on the VLAN: