Multiple learning domains for a bridge domain or VPLS instance are implicitly created with the vlan-id all statement. This statement provides a mechanism to configure bridging for several VLANs with a minimal amount of configuration and switch resources.
The vlan-id all statement implicitly creates a learning domain for:
A learning domain is a MAC address database where the MAC addresses are added based on the normalized VLAN tags. The normalized VLAN tags associated with a learning domain are always carried within packets sent over VPLS virtual interfaces.