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Ethernet turns 40 years old today

From local area to worldwide deployment
Wed May 22 2013, 00:00
Ethernet cable

FOUR DECADES AGO the Ethernet protocol made its debut as a way to connect machines in close proximity, today it is the networking layer two protocol of choice for local area networks (LANs), wide area networks (WANs) and everything in between.

For many people Ethernet is merely the RJ45 jack on the back of a laptop, but its relative ubiquity and simplicity belie what Ethernet has done for the networking industry and in turn for consumers and enterprises. Ethernet has in the space of 40 years gone from a technology that many in the industry viewed as something not fit for high bandwidth, dependable communications to the default data link protocol.

Ethernet for the first two decades was deployed widely in LANs, competing and winning against Token Ring networks and various other more exotic and costly technologies. What Ethernet had going for it was the relatively low cost of network interface cards (NICs) and switching equipment, as well as the fact that its adaptive data link protocol that tolerated ad hoc LAN segment configuration and device connections and disconnections made it far easier and less expensive to implement and maintain.

While IBM's Token Ring technology had both the brand name and the bandwidth to match Ethernet, a standard that had been ratified by the Institute of Electrical and Electronics Engineers (IEEE) as 802.3, its switch gear equipment, physical wire and network engineering overhead were significantly more expensive, making Ethernet based LANs more attractive.

Now Ethernet sockets and network interface circuitry can be found on most laptops and desktop motherboards, but back in the 1990s hardware vendors would sell separate network interface cards (NICs) that supported 10BASE-T, a standard that provided 10Mbit/s over twisted copper pairs. Eventually the IEEE ratified what would be commonly known as 100BASE-T, resulting in 100Mbit/s bandwidth over copper and today it is common to find 1000BASE-T, or gigabit Ethernet, supported by most NICs.

Ethernet's deployment over copper is arguably what made it as successful as it is today. Even when the IEEE ratified the 802.3 standard, by which time Ethernet was 10 years old, it still used coaxial cable as the physical cable, but copper twisted pair wires - effectively the same cabling used in the telephone system - were found to work just as well, offering simplicity and once again lower cost.

Now Ethernet is deployed not just over copper wires, usually labeled as unshielded twisted pair (UTP), but fibre optic cables. Ethernet over fibre optic cables is usually first to see bandwidth increases and offers greater range, especially when deployed in single mode.

But Ethernet's biggest accomplishment is away from the LAN and in the telecoms industry that in the past used protocols such as synchronous data hierarchy (SDH) and asynchronous transfer mode (ATM). Henry Bohannon, senior director and head of Ethernet Product Management at Tata Communications told The INQUIRER that Ethernet was initially viewed as an unreliable technology but has now matured into one to which transit providers can attach service level agreements (SLAs).

Bohannon said, "People associated it with a being a LAN technology so they weren't confident it was robust in the WAN. But now it has gained a lot more acceptance and people are seeing you have same types of SLA in terms of guarantees of availability, uptime, time to repair just like you have with traditional technologies so there is no difference. [...] People now have a level of confidence that [Ethernet] has been engineered as a WAN technology."

Bohannon added that as enterprises already had knowledge of deploying and managing Ethernet within LAN environments, deploying Ethernet over WANs such as point-to-point links between offices or over the internet was a logical step. While firms can still pick up SDH or ATM links, it is unlikely that telecoms operators such as BT are seeing very much demand from enterprises, especially given the choice of providers in the market for internet protocol (IP) transit over Ethernet.

Ethernet might be a 40 year old technology, but thanks to the IEEE's relentless push to increase bandwidth and transit providers' ability to attach reliability guarantees, it means there is a good chance that Ethernet will not only reach its half century with ease but continue to be widely deployed even 20 years or more from now. There are very few technologies in use today that can lay claim to being 40 years old and still on the cutting edge, but Ethernet can. µ

 

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