The History of Ethernet

The history of Ethernet technology has been around since the 1970s, devised as a local area network (LAN) protocol used to link computers and transfer information across short distances, often several hundred yards or less. Over the years Ethernet history has bested competing local network technologies, including token ring, FDDI and ATM, to become utterly dominant as an inexpensive plug-and-play LAN protocol. The latest generation of carrier Ethernet services is the result of service providers responding to the demand by enterprise customers for a simple way to connect their premises networks across metro and wide area networks. Enterprise IT departments like the idea of an Ethernet service that represents an extension of familiar LAN networks across metropolitan areas, instead of having to deal with the (to them) puzzling world of telco standards such as SONET, frame relay and ATM. Finally, Ethernet is also emerging as an access alternative to TDM circuits, providing enterprise customers with high bandwidth access to the Internet, or to an IP VPN service, or to a data center, without incurring the higher cost of WAN interface cards on the routers.

While all customer-facing Ethernet ports may look alike, the underlying approaches used to transport Ethernet traffic across carrier networks vary greatly, which is reflected in factors such as service price, available bandwidth, network performance, class of service and service level guarantees.

The original transparent LAN services were most often supported by the incumbent local telco’s ATM networks in the 1990s, and some of these services are still operated that way today. Once Ethernet’s dominance in the LAN solidified in the late 1990s and beyond, carriers began installing enterprise-class Ethernet switches in central offices to provide service within a metropolitan area. However, as the number of customers grew, this approach soon ran into stability, capacity and scaling issues, and providers turned to carrier-grade switches and routers to support the burgeoning demand for metro Ethernet services.

Today, carrier Ethernet is most commonly transported over dedicated fiber optic lines to the customer premises, and Ethernet-over-SONET services are available for those willing to pay for higher availability. Carrier Ethernet services are also available on alternative transport technologies, such as resilient packet ring (RPR) protocol (802.17) for multipoint connectivity within a metro area, or encapsulated in MPLS for transport over carriers’ IP backbone networks. Ethernet on a wavelength is also available for large customers, while at the low end, some carriers are rolling out mid-band Ethernet using copper pair bonding techniques to deliver up to 10 Mbps or more at distances of one to two miles from the central office. The cable multi-system operators (MSOs) are also moving into the metro Ethernet market, drawing on their extensive regional fiber optic networks and local access facilities. At the same time, the cable operators have also moved down market in the past year with the advent of Ethernet over DOCSIS-enabled hybrid fiber coax (HFC) networks, which allows them to reach the 90+ percent of business sites that are not served by fiber optics.