Ethernet at 50: Why It's Still the Backbone of Networking

The faithful Ethernet cable (and its supposed protocol) turns 50 years old, and despite its age, it continues to power network infrastructure all around the world. How has Ethernet changed over the years, why does it remain a popular choice for engineers, and what does the future hold for Ethernet?

 Fiber optic cables and UTP network cables are linked to hub ports.  

How has Ethernet changed over the years?

Ethernet, the ubiquitous networking technology that forms the backbone of modern local area networks (LANs), has a rich history spanning several decades. From its humble beginnings as a research project to its widespread adoption across industries, Ethernet has revolutionised the way we connect and communicate.

The story of Ethernet begins in the early 1970s at Xerox Corporation’s Palo Alto Research Center (PARC). In 1973, Dr Robert Metcalfe, a computer scientist, and his team embarked on a project to connect computers and peripheral devices in a local network. This project, known as the “Alto Aloha Network,” laid the foundation for what would eventually become Ethernet. For instance, the Alto computer, developed at Xerox PARC, was one of the first to use Ethernet for networking. This marked a significant milestone in the evolution of networking technology.

In 1976, Metcalfe and his team introduced the Ethernet concept in a paper titled “Ethernet: Distributed Packet-Switching for Local Computer Networks”, whereby they proposed a packet-switching network that utilised a shared coaxial cable, known as the “Ethernet cable”, to enable multiple computers to communicate simultaneously. This paper, published in the Communications of the ACM, is widely regarded as a seminal work in the field of computer networking. You can read more about it on the ACM Digital Library. 

In 1980, the Institute of Electrical and Electronics Engineers (IEEE) formed a committee to develop Ethernet standards. The committee released the first Ethernet standard, known as “Ethernet Version 1.0” or “Ethernet DIX,” which specified a data rate of 10 Mbps and the use of a coaxial cable. This standard laid the groundwork for Ethernet’s rapid expansion. Throughout the rest of the decade, Ethernet gained popularity as a reliable and cost-effective networking technology. Its flexibility and scalability made it the preferred choice for connecting computers, printers, and other devices within organisations. As Ethernet’s popularity grew, advancements such as twisted-pair cabling and the introduction of Ethernet hubs further enhanced its capabilities.

Ethernet was commercially introduced in 1980 and first standardised in 1983 as IEEE 802.3. The original 10BASE5 Ethernet used a thick coaxial cable as a shared medium. This was largely superseded by 10BASE2, which used a thinner and more flexible cable that was both cheaper and easier to use. More modern Ethernet variants use twisted pair and fiber optic links in conjunction with switches. Over the course of its history, Ethernet data transfer rates have been increased from the original 2.94 Mbit/s to the latest 400 Gbit/s, with rates up to 1.6 Tbit/s under development. The Ethernet standards include several wiring and signaling variants of the OSI physical layer. 

In the 1990s, demand for higher data transfer rates spurred the development of Fast Ethernet. Introduced in 1995, Fast Ethernet achieved speeds of 100 Mbps, ten times faster than its predecessor. This advancement enabled more efficient network communication and facilitated the growth of multimedia applications. Building on the success of Fast Ethernet, Gigabit Ethernet emerged in the late 1990s, offering data rates of 1 Gbps. This breakthrough opened up new possibilities for bandwidth-intensive applications and expanded Ethernet’s reach into areas like video streaming, high-performance computing, and data centres. For example, companies like Netflix and Amazon Web Services heavily rely on Gigabit Ethernet for their data-intensive operations, demonstrating the critical role of Ethernet in the modern digital economy.

As the world embraced wireless technologies, Ethernet also adapted to the changing landscape. In the early 2000s, the IEEE introduced the 802.11 standard, commonly known as Wi-Fi, which enabled wireless Ethernet connectivity. Wireless LANs (WLANs) became prevalent, offering the convenience of mobility without sacrificing network connectivity. You can learn more about the development of the 802.11 standard on the IEEE's official website. 

In recent years, Ethernet has continued to evolve to meet the ever-increasing demands of modern networking. The development of 10 Gigabit Ethernet (10 Gbps) and higher-speed variants, such as 40 Gigabit Ethernet and 100 Gigabit Ethernet, has propelled Ethernet into the realm of high-performance computing and data-intensive applications.

Furthermore, Power over Ethernet (PoE) technology has emerged, enabling devices such as IP phones, wireless access points, and security cameras to receive power and data over a single Ethernet cable. This innovation simplifies installations and reduces the need for additional power sources. Today, Ethernet remains the dominant technology for local area networks, connecting billions of devices worldwide. Its versatility, reliability, and constant evolution ensure that it will continue to play a vital role in the future of networking.

Why does Ethernet remain a popular choice for engineers?

Despite Ethernet hitting the ripe old age of 50 years, it continues to dominate networking infrastructure all over the world. But what exactly is it about Ethernet that gives it such massive amounts of popularity, and why hasn’t the cable design or topology changed?

Undoubtedly, its standardised nature is the most significant factor in its popularity. Just like how USB allows devices from different manufacturers to communicate with each other over standardised cables, Ethernet standards are well defined, including the physical connections and the protocols used, meaning that most ethernet devices can communicate. Of course, the physical characteristics of cables can affect the maximum data bandwidth and the longest cable length that can be run, but these do not interfere with the termination of cables or how data is transmitted.

Another reason for its popularity comes from its scalability. The ability to scale ethernet networks was one of the primary focus points that its designers wanted, and retaining this ability has allowed engineers to create massive computer networks. This is especially true in data centres consisting of thousands of server racks that all need to communicate with each other to provide ultra-fast services to clients all around the world. For more detailed information on how Ethernet is used in data centres, you can refer to this comprehensive guide on Ethernet in Data Centres on Wikipedia.

Improvements in electronics and cable technologies have also allowed for ethernet cables to handle high bandwidths over large distances. Cables beyond 10Gbps have already been deployed, with 1Gbps cables now commonly found in the home. This is significantly faster than that of Wi-Fi or other network technologies, which struggle as more devices are connected.

Overall, engineers continue to choose Ethernet for its ubiquity, scalability, high data transfer rates, reliability, flexibility, and support for converged networks. Ethernet’s ability to adapt to changing networking requirements, industry support, and continuous innovation make it a trusted and preferred choice for engineers in a wide range of applications and industries.

Ethernet's influence extends far beyond the realm of computer networks. It is widely used in homes and industry and interworks well with wireless Wi-Fi technologies. The Internet Protocol is commonly carried over Ethernet, making it a key technology that underpins the Internet. As Industrial Ethernet is used in industrial applications and is quickly replacing legacy data transmission systems in the world's telecommunications networks. By 2010, the market for Ethernet equipment amounted to over $16 billion per year, reflecting its widespread adoption and critical role in various industries.

What does the future hold for Ethernet cables?

It is highly likely that as technology improves, so will the capabilities of ethernet cables, and it is likely that speeds exceeding 100Gbps will become commonplace in data centres and servers. The protocols used by ethernet networks will also see changes to support new features, such as software-defined networks that will allow for virtualisation, and it is also likely that new security protocols will be deployed to protect them against new attacks.

But it is also possible that ethernet cables will be replaced with optical systems while still retaining the same receptacle and protocols. Copper cables can only do so much, and there are physical limitations when trying to operate at speeds in the terahertz, but this is something that fibre optic systems can easily handle. Additionally, fibre optics can not only handle multiple different frequencies simultaneously but can use the same frequency in both directions without causing interference. For a deeper understanding of how optical systems could replace Ethernet cables, this YouTube video provides a comprehensive explanation.

The future regarding Ethernet is truly exciting, and there are numerous technologies that can be used to improve Ethernet in a multitude of ways. It is unlikely that the cable will be going anywhere soon, and the protocol that is used over ethernet cables will only continue to improve in bandwidth and efficiency.

However, the journey of Ethernet hasn't been without challenges. Initially, Ethernet had to compete with Token Ring and other proprietary protocols. It was able to adapt to market needs and shift to inexpensive thin coaxial cable with 10BASE2 and to the now-ubiquitous twisted pair with 10BASE-T. By the end of the 1980s, Ethernet was clearly the dominant network technology. 

Despite the physical star topology and the presence of separate transmit and receive channels in the twisted pair and fiber media, repeater-based Ethernet networks still use half-duplex and CSMA/CD, with only minimal activity by the repeater, primarily generation of the jam signal in dealing with packet collisions. Every packet is sent to every other port on the repeater, so bandwidth and security problems are not addressed. The total throughput of the repeater is limited to that of a single link, and all links must operate at the same speed. To alleviate these problems, bridging was created to communicate at the data link layer while isolating the physical layer. With bridging, only well-formed Ethernet packets are forwarded from one Ethernet segment to another; collisions and packet errors are isolated. 

This innovation marked a significant step forward in the development and implementation of Ethernet, demonstrating its resilience and adaptability in the face of challenges.