Automatically Binding Ports

To automatically bind ports to an STPD (Spanning Tree Domain) when the ports are added to a VLAN, use the command:
enable stpd stpd_name auto-bind vlan vlan_name

The autobind feature is disabled on user-created STPDs. The autobind feature is enabled on the default VLAN that participates in the default STPD S0.

For EMISTP or PVST+, when you issue this command, any port or list of ports that you add to the carrier VLAN are automatically added to the STPD with autobind enabled. In addition, any port or list of ports that you remove from a carrier VLAN are automatically removed from the STPD. This feature allows the STPD to increase or decrease its span as ports are added to or removed from a carrier VLAN.

Note
The carrier VLAN's ID must be identical to the ID of the STP domain.
Enabling autobind on a protected VLAN does not expand the boundary of the STPD.

If the same set of ports are members of the protected VLAN and the carrier VLAN, protected VLANs are aware of STP state changes. For example, assume you have the following scenario:
- Carrier VLAN named v1
- v1 contains ports 3:1-3:2
- Protected VLAN named v2
- v2 contains ports 3:1-3:4
Since v1 contains ports 3:1-3:2, v2 is aware only of the STP changes for ports 3:1 and 3:2, respectively. Ports 3:3 and 3:4 are not part of the STPD, which is why v2 is not aware of any STP changes for those ports.

In addition, enabling autobind on a protected VLAN causes ports to be automatically added or removed as the carrier VLAN changes.

For MSTP (Multiple Spanning Tree Protocol), when you issue this command, any port or list of ports that gets automatically added to an MSTI (Multiple Spanning Tree Instances) are automatically inherited by the CIST. In addition, any port or list of ports that you remove from an MSTI protected VLAN are automatically removed from the CIST. For more information, see Automatically Inheriting Ports--MSTP Only.
To remove ports, enter the command:
configure stpd stpd_name delete vlan vlan_name ports [all | port_list]

If you manually delete a port from the STPD on a VLAN that has been added by autobind, ExtremeXOS records the deletion so that the port does not get automatically added to the STPD after a system restart.

To learn more about the member VLANs, see Member VLANs. For more detailed information about these CLI commands, see the ExtremeXOS 22.2 Command Reference Guide.

Published March 2020prev | next

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