The Evolution of Ethernet and Carrier Ethernet

- The History of Traditional Ethernet

First developed by Xerox PARC in the 1970s and ratified by IEEE as a standard in 1983, the evolution of Ethernet has taken this LAN technology through dozens of specifications. 

For hundreds of years, scientists believed a mysterious substance known as ether served as the medium for light to disperse through space. 

The notion was ultimately dismissed once physicists discovered that photons act as both particles and waves. But the archaic word lives on in the modern term Ethernet - the technology by which bits of information travel through complex computer networks.

- Traditional Ethernet - The First Local Area Network (LAN)

The first LAN in the world was the original version of Ethernet. Robert Metcalfe and his coworkers at Xerox designed it more than forty years ago. On May 22, 1973, Bob Metcalfe (then at the Xerox Palo Alto Research Center, PARC, in California) wrote a memo describing the Ethernet network system he had invented for interconnecting advanced computer workstations, making it possible to send data to one another and to high-speed laser printers.

The first Ethernet standard was published in 1980 by a consortium of Digital Equipment Corporation, Intel, and Xerox (DIX). Metcalfe wanted Ethernet to be a shared standard from which everyone could benefit, and therefore it was released as an open standard. 

The first products that were developed from the Ethernet standard were sold in the early 1980s. In 1985, the Institute of Electrical and Electronics Engineers (IEEE) standards committee for Local and Metropolitan Networks published standards for LANs. These standards start with the number 802. The standard for Ethernet is 802.3. 

The IEEE wanted to make sure that its standards were compatible with those of the International Standards Organization (ISO) and OSI model. To ensure compatibility, the IEEE 802.3 standards had to address the needs of Layer 1 and the lower portion of Layer 2 of the OSI model. As a result, some small modifications to the original Ethernet standard were made in 802.3.

Ethernet operates in the lower two layers of the OSI model: the Data Link layer and the Physical layer. Ethernet uses CSMA/CD when transmitting packets. The Carrier Sense Multiple Access with Collision Detection (CSMA/CD) is an algorithm, for transmitting and receiving packets over a common network hardware medium, by aiding in avoiding transmission collisions.

- The History of Carrier Ethernet

Carrier Ethernet (CE) is a marketing term for extensions to Ethernet to enable telecommunications network providers to provide Ethernet services to customers and to utilize Ethernet technology in their networks. The CE story is today moving on. New capabilities and features are being deployed that go further than the minimum requirements established by the Metro Ethernet Forum (MEF), ushering in the age of Carrier Ethernet (CE).

Carrier Ethernet supports 802.1ad Provider Bridging and can deliver and transport MEF services using MPLS/ H-VPLS and PBB-TE technologies, along with SDH-like 50ms restoration capabilities.  By supporting these important technologies, Carrier Ethernet enables carriers to leverage existing network investments and select, mix, and match the wide-area services that best meet their needs today and in the future.

Carrier Ethernet builds on all the advantages of Ethernet by providing a flexible framework, universal frame format, simple design, and enhanced Operations, Administration, and Maintenance (OAM) capabilities for high-performance networks ideally suited for both enterprises and carriers. And like Ethernet, the growing adoption of Carrier Ethernet is changing how networks are built.

Carrier Ethernet is commonly employed in industries such as banking, healthcare, education, government, and military for high-capacity, high-performance application support. A growing number of operators are building on these CE connectivity services to provide enhanced managed services using Software-Defined Networking (SDN) and Network Functions Virtualization (NFV) technologies. 

Carrier Ethernet innovation is moving at an impressive pace. Between the various industry groups and standards bodies, as well as multiple concurrent standards efforts, it’s often hard to keep up. To make sense of it all, here is an overview of the speeds, standards and services associated with Carrier Ethernet. 

- Carrier Ethernet versus Traditional Ethernet

The primary attributes of Carrier Ethernet that differentiates it from traditional Ethernet are:

• A Carrier Ethernet network provides service to many organizations, while an Ethernet LAN renders service to only one organization.
• A Carrier Ethernet network covers a wide area and so spans outside a single building. On the other hand, an Ethernet serving a LAN is typically located within a building.
• For connecting to a Carrier Ethernet, the entire organization connects to a particular carrier Ethernet port; while, in Ethernet LAN each user connects to a dedicated Ethernet port.

(800G MAC High Level Block Diagram - The Ethernet Technology Consortium)

- Carrier Ethernet Speeds

Ethernet is a popular method of networking computers in a local area networks (LANs) using copper cabling. In the past, Ethernet had a reputation for being slower than fiber optic cable, but that has started to change. Ethernet speed was once limited to 10 megabits per second (Mbps). However, “Fast Ethernet” offers speeds of up to 100Mbps, and “Gigabit Ethernet” can provide speeds of up to 1000Mbps. 

Ethernet network speeds have evolved significantly over time and typically range from Ethernet (802.11) at 10 Mbps, Fast Ethernet (IEEE 802.3u) at 100 Mbps, Gigabit Ethernet (IEEE 802.3-2008) at 1000 Mbps and 10 Gigabit Ethernet (IEEE 802.3a) at 10 Gbps. In fact, history shows that Ethernet bit rates grow tenfold each time a new rate is defined. Gigabit Ethernet (GbE) interfaces are widely deployed in PCs and servers, and 10 Gb/s is quickly becoming the standard for LAN backbones. 

But there is a new trend in the evolution of Ethernet where new data rates are envisioned that support specific applications, instead of the habitual 10x rate leap we’ve seen in the past. The 2.5Gb/s rate, for instance, is envisioned specifically to address connecting WiFi access points capable of more than 1Gb/s but nowhere near 10Gb/s. Since cost is of paramount concern in this environment, this rate makes a lot of sense for enterprises and real-estate tenants/landlords. 

Similarly 5Gb/s and 25Gb/s find specific applications in the data center environment. Interestingly, the Ethernet Alliance chart does not show the next logical 10x rate (1Tb/s) given some technical challenges that will probably push it out beyond the chart’s time horizon, but rest assured, with bit rates in the hundreds of Gb/s and extensions to the standard continuously under development the increasing Ethernet speeds won’t abate any time soon. 

Just as the stage is set for 400G Ethernet (GbE) to roll out in force later 2020, mainly in hyperscaler, telco and large data-center networks, there is a call to boost that speed to 800GbE or even higher in the coming years.

- 800 Gigabit Ethernet Technology

The Ethernet Technology Consortium is the new name for the group previously known as ‘The 25 Gigabit Ethernet Consortium’. While the original name clearly reflected the group’s aim, the rebranding of the consortium is to “reflect a new focus on higher-speed Ethernet technologies”. Now, Ethernet Technology Consortium – or ETC for short – has announced the 800 Gigabit Ethernet specs.

The brief explanation for how the leap in Ethernet technology is achieved is through using already existing 106.25 Gb physical lanes - 8 of them together. This pushes the speed all the way up to 800 Gb/s which means that, at least in theory, it’s possible to transfer a 100 GB file over Ethernet in one second. However, it’s worth emphasizing that in practice bottlenecks may bring down the speed to lower than what is specified.

With an increasing demand for networking speed and throughput performance within the datacenter and high performance computing clusters, the newly rebranded Ethernet Technology Consortium  has announced a new 800 Gigabit Ethernet technology. Based upon many of the existing technologies that power contemporary 400 Gigabit Ethernet, the 800GBASE-R standard is looking to double performance once again, to feed ever-hungrier datacenters.