B&B Electronics 856-14205--29 - Manual - Manual (Page 27)

Configuration
22
By default, the device is set up to access ports. However, one must be
configured to be a trunk port.
The Optics port and the Data port can be configured as an access port or a trunk
port. When configuring as a trunk port, an Ethertype can be user-defined (a
trunk port is also defined as a provider port, based on 802.1ad). If an Ethertype
value come in a trunk port and is different than the user-defined Ethertype, it