Definition: Carrier Ethernet

A standard for carrier-class Ethernet services for network service providers. Carrier Ethernet extends Ethernet from the local area network (LAN) to the wide area network (WAN), enabling companies to connect their Ethernet LANs to service provider networks via the same Ethernet interface they use to attach every device in the network. It provides a transparent LAN service that bridges LANs in separate locations together as if they were one network. An administrator can manage a global Ethernet network using virtual LAN tools, which group computers together logically no matter where they physically reside. See virtual LAN and carrier class.

Using traditional TDM and SONET backbones, service providers have taken days and weeks to establish wide area networks for new customers and make subsequent changes. Since Carrier Ethernet connects to a LAN using Ethernet plugs and sockets, new customers can be hooked up to Gigabit Ethernet and 10 Gigabit Ethernet interfaces in a much shorter time. See TDM and SONET.

From Local Networks to Subscriber Networks
Residing within a building or campus, almost all business networks are Ethernet. In order to extend Ethernet to a global network that serves multiple customers, Ethernet had to be extensively upgraded to handle fault tolerance, levels of service and continuous changes in a timely manner. For detailed information about the standards, visit the Metro Ethernet Forum (MEF).

MPLS for Service Quality
Most LAN traffic is IP based; therefore the bulk of all Carrier Ethernet traffic is IP packets. Since MPLS is a method for providing quality of service (QoS) in an IP network, it can also be used to ensure quality levels in a Carrier Ethernet network. See MPLS and QoS.

Carrier Ethernet Over SONET
Although Carrier Ethernet is designed to transport Ethernet frames natively (layer 2 in the OSI model), network providers can deploy it over legacy point-to-point SONET circuits. Carrier Ethernet can also ride directly over fiber (see WDM).

Ethernet Virtual Connection (EVC) Topology
Carrier Ethernet is based on a virtual connection between two user network interface (UNI) points. An "E-Line" is one EVC (point-to-point), whereas an "E-LAN" offers a multipoint EVC topology just like any local network. See Metro Ethernet.

Private or Virtual Point-to-Point

There are two types of point-to-point E-Line connections: an Ethernet Private Line (EPL) is a dedicated connection between two points, whereas an Ethernet Virtual Private Line (EVPL) is shared with other network connections.

Multipoint Topology

An E-LAN provides a multipoint topology like a local network. Each node can reach any other node.