MPLS
A Multiprotocol Label Switching (MPLS) metro Ethernet network uses MPLS in the service provider's network. The subscriber will get an Ethernet interface on copper (for example, 100BASE-TX) or fiber (such as 100BASE-FX). The customer's Ethernet packet is transported over MPLS and the service provider network uses Ethernet again as the underlying technology to transport MPLS. So, it is Ethernet over MPLS over Ethernet.