Guidelines for Configuring VLAN Identifiers for Bridge Domains and VPLS Routing Instances
For a bridge domain that is performing Layer 2 switching only, you do not have to specify a VLAN identifier.
For a bridge domain that is performing Layer 3 IP routing, you must specify either a VLAN identifier or dual VLAN identifier tags.
For a VPLS routing instance, you must specify either a VLAN identifier or dual VLAN identifier tags.
