Metro Ethernet is the use of telco carrier-supported Ethernet technology in metropolitan area networks (MANs) or Wide Area Networks (WANs) vs. using Ethernet technology for just a Local Area Network (LAN), the most widely used application for the Ethernet protocol.

Because it is typically a collective endeavor with numerous financial contributors, Metro Ethernet offers cost-effectiveness, reliability, scalability and bandwidth management superior to most proprietary networks. Metro Ethernet can connect businesses LANs and individual end users to a WAN or to the Internet. Corporations, academic institutions and government agencies in large cities can use Metro Ethernet to connect branch campuses or offices to an intranet.

A typical Metro Ethernet system has a star network or mesh network topology with individual routers or servers interconnected through cable or fiber optic media. This allows for optimum reliability and scalability.

"Pure" Ethernet technology in the MAN environment is relatively inexpensive compared with Synchronous Digital Hierarchy (SDH) or Multiprotocol Label Switching (MPLS) systems of similar bandwidth. However, the latter technologies can be applied to Metro Ethernet in urban areas willing to devote the necessary financial resources to the task.