A L2 sub-interface is a logical bridging endpoint associated with traffic on an interface distinguished by 802.1Q tags, where each <interface, 802.1Q tag> tuple is treated as a first-class bridging interface. 

Ingress policing provides the ability to monitor the data rates for a particular class of traffic and perform action when traffic exceeds user-configured values. This allows users to control ingress bandwidth based on packet classification.  Ingress policing is done by a policing meter which marks incoming traffic and performs actions based on the results of policing meters. 

The Interface Reflector feature allows performing certain actions (such as source/destination MAC address swap) on bridged packets that are reflected back from the interface. It is useful to test properties and SLAs before deploying the service for a customer.