Asynchronous Transfer Mode is a network protocol that encodes data traffic in small cells, designed to facilitate the movement of large amounts of rich data over wide areas, now being gradually superseded by carrier Ethernet.


Dense Wavelength Division Multiplexing combines data from different sources on an optical fibre, with each signal carried on its own separate light wavelength. Often used with Ethernet running over it.


Ethernet in the First Mile, also known as IEEE 802.3ah, is a group of protocols defining how Ethernet works at access network level.


Ethernet Local Management Interface is an Ethernet layer operation, administration and management (OAM) protocol, allowing for configuration of customer edge devices.


Ethernet Operations, Administration, and Maintenance (OAM) is a protocol for installing, monitoring, and troubleshooting Ethernet metro networks and WANs.


Ethernet over MPLS is useful for the consolidation of multiple services over a single user network interface, and provides a cost-effective alternative to Ethernet over SDH/Sonet, Ethernet over DWDM and Ethernet over copper.


Ethernet Passive Optical Network is an IEEE standard for using Ethernet for packet data, with around 25 million installed subscribers.


Ethernet Private Line is a data service providing a point-to-point connection between a pair of dedicated User Network Interfaces (UNIs). To be distinguished from Ethernet Virtual Private Line (EVPL), which does much the same via a point-to-point Ethernet Virtual Connection (EVC), allowing for multiple EVCs or Ethernet services per UNI.


The Institute of Electrical and Electronics Engineers – a not-for-profit body promoting common standards in electronics and computing.


The Internet Engineering Task Force develops and promotes internet standards on a global basis.

Long-haul Ethernet

Ethernet is becoming an increasingly important aspect of the international WAN market, with many carriers adding new Ethernet offerings to their WAN service portfolios as an alternative to ATM, Frame Relay, SDH/Sonet and Layer 3 IP-VPN products.

Metro Ethernet Forum

MEF is a global industry coalition, comprised of more than 170 organisations from carriers to software vendors. It is dedicated to worldwide awareness of the benefits of Ethernet services and networks.


A virtual circuit that tunnels through an MPLS cloud providing a standalone, point-to-point connection between two offices, generally at a lower cost compared to a port-based VPLS service (see VPLS).

Frame Relay

A service designed for cost-efficient transmission of data traffic between LANs and endpoints in a WAN. Based on X.25 packet-switching technology which was designed for transmitting analogue data, but faster. Now largely outdated itself.


A network-to-network interface is an arrangement specifying signalling and management functions between two networks. An eNNI is an NNI between two Ethernet networks.


Multi Protocol Label Switching was designed to provide a unified data-carrying service for both circuit-based clients and packet-switching clients, and can be used to carry many different types of traffic including IP packets, native ATM, Sonet and Ethernet frames.


Quality of Service encapsulates the idea that transmission rates, error rates and other network characteristics can be measured, improved on and, to some extent, guaranteed in advance.


Virtual Private LAN Service is a way to provide Ethernet-based multipoint-to-multipoint communications over IP/MPLS networks, making it possible to connect LANs over the internet so they appear to users like a single Ethernet LAN. VPLS port-based services generally apply to large, multi-site applications.

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