Ethernet Evolution in Computer Networks

Today Ethernet is the world’s leading provider of LAN (Local Area Network) technology. In a May 22, 1973 note, Bob his Metcalf, who was then working at Xerox’s Palo Alto Research Center (PARC) in California, used his computer to connect to a high-tech workstation and allow high-speed data transfer. He described an Ethernet network system created for printers. Xerox Alto was the first personal computer workstation with a graphical user interface and a mouse pointer and is perhaps his Xerox PARC’s most famous product. PARC also invented the first laser printer for PCs and Ethernet, the first high-speed LAN technology to connect everything.

The discoveries made at Xerox PARC helped fundamentally transform the computer industry. The introduction of the Ethernet LAN, which facilitated computer communication, played a key role in this fundamental change in the way computers are used. This new computing architecture has spawned a whole new world of communication technology, along with the explosive growth in the use of information-sharing applications such as the World Wide Web. Today, the Ethernet is the network technology of choice for the transmission of information. Ethernet is used in small offices to large enterprises, from small classrooms to large university campuses.

Aloha Network:

An early network experiment known as the Aloha Network became the basis for the network technology described in Bob Metcalf’s 1973 paper on Ethernet. The Aloha Network began in the late 1960s when Norman Abramson and his colleagues at the University of Hawaii created a wireless network to communicate throughout the Hawaiian Islands. This system served as an early development prototype for how to share a single communication channel, in this case, a radio channel.

Aloha stations can send whenever they want and then wait for an acknowledgment, according to the fairly straightforward Aloha protocol. The station assumed that another station had been transmitted simultaneously, leading to a collision in which the combined transmissions were garbled such that the receiving station could not hear them and did not respond with an acknowledgment if an acknowledgment was not received within a brief period of time. Both transmitting stations would pick a random backoff time after detecting a collision and would then resend their packets with a high chance of success. On the Aloha channel, however, as traffic grew, the rate of collisions also grew quickly.

Because collision rates increase rapidly with increasing load, Abramson estimated that this system, known as Pure Aloha, could achieve a maximum channel utilization of about 18%. Maximum channel utilization increased to about 37% using another technique called Slotted Aloha, which assigns transmission slots and uses a master clock to synchronize transmissions. Abramson was awarded the IEEE Koji Kobayashi Computers and Communications Award in 1995 for “creating the concept of the Aloha system that gave rise to modern local area networks.”

The Emergence of Ethernet:

Metcalfe concluded that it could mediate access to common communication channels better than the Aloha system. He created a new system that includes a mechanism for detecting collisions (collision detection). This system allows access to a shared channel through a large number of stations and enables integrated “listen-before-talk” where stations listen for activity (carrier detection) before transmission (multi-access). Combining all these elements, you can see why the Ethernet Channel Access Protocol is called Carrier Sense Multiple Access With Collision Detect (CSMA/CD). Metcalfe developed a more advanced backoff algorithm that allowed Ethernet systems to operate at up to 100% utilization. The first experimental Ethernet system was developed by Metcalfe and his Xerox PARC employees in late 1972 to connect the Xerox Alto. Altos was connected to servers, laser printers, and other devices via experimental Ethernet. Alto’s system clock served as the source of the signal clock for an experimental Ethernet interface with a data transfer rate of 2.94 Mbit/s.

The Alto Aloha Network was Metcalfe’s first experimental network. Metcalf named his 1973 name “To emphasize that this system could handle any computer, not just the Altos, he wrote ‘Ethernet’, and his new network mechanism was far beyond the system Aloha.  He decided to use the term based on the word “ether” to describe the key aspects of the system. Just like in old networks, a physical medium (such as a cable) delivers bits to all stations. Pass through glowing ethereal space. 

In late 1977 and mid-1978 when patents were granted on Ethernet and for Ethernet repeaters. At this point, Xerox was the sole owner of the Ethernet network. The next step in the evolution of the world’s most widely used computer network was to free Ethernet from corporate restrictions and make it a universal standard.

Ethernet Evolution Standard:

A collaboration between DEC-Intel-Xerox vendors released the first 10Mbps Ethernet standard in 1980. The DIX Ethernet standard became known as the first initials of the companies. Called Ethernet, this standard, Local Area Networks: Data Link Layer and Physical Layer Specifications, included details for both Ethernet-based single-media systems and thick coax-based single-media systems. The DIX standard has been updated and, like most standards, includes some technical tweaks, fixes, and minor improvements. DIX V2.0 is the latest version of this standard.

When the DIX standard was released, a new initiative to create open network standards under the direction of the Institute of Electrical and Electronics Engineers (IEEE) was also beginning. [3] As a result, the thick coaxial variant of Ethernet was ultimately standardized twice once by the IEEE and once by the DIX consortium. The IEEE Local and Metropolitan Networks (LAN/MAN) Standards Committee, which gave the standard its designation of 802, oversaw the creation of the IEEE standard. The IEEE 802 branch has released a number of networking standards, including the 802.3 Ethernet and 802.5 Token Ring standards.

The initial DIX network system was adopted by the IEEE 802.3 committee and utilized as the foundation for an IEEE standard. With the title IEEE 802.3 Carrier Sense Multiple Access with Collision Detection (CSMA/CD) Access Method and Physical Layer Specifications, the IEEE standard was initially released in 1985. Even though Xerox gave up its trademark under the name “Ethernet,” the IEEE standard does not include it in the title. This is because open standards groups are very cautious about adopting brand names that could be interpreted as endorsing a certain business. IEEE refers to this technology as 802.3 CSMA/CD or just 802.3. When referring to the network system outlined in the 802.3 standards, the majority of people still use the name Ethernet.

The recognized Ethernet standard is IEEE 802.3. You might occasionally hear of new “standards” for Ethernet technology being created by different organizations or vendor consortiums. However, technology is not recognized as an official Ethernet technology if it is not described in the IEEE 802.3 standard. The most recent IEEE 802.3 standards are periodically provided to the American National Standards Institute (ANSI), which then sends them on so that the International Organization for Standardization can adopt them (ISO). 

IEEE Standardization:

• The first 10 Mbps Ethernet specification was published in 1980 by Xerox in collaboration with two other vendors, Digital Equipment Corporation and Intel. At the same time, the IEEE Standards Committee for Local and Metropolitan Area Networks (LAN/MAN) began work on an equivalent open standard.
  Called 802.3 by the LAN/MAN committee, an Ethernet subcommittee was formed to give all standards the number 802. 
• The original 802.3 standards for Thick Ethernet (10Base-5) were adopted by IEEE in 1983 and officially published in 1985. Twisted pairs (10Base-T), fiber optic (10Base-FL), and 802.3a (10Base-2) (a 10 Mbps Ethernet variant using thin coaxial cable) were his next two standards to be ratified. 
• Fast Ethernet, sometimes called 100BASE-T or 100Mbps Ethernet, debuted in 1995 and introduced auto-negotiation. With this new feature, you can now connect two network devices and choose the appropriate speed and duplex mode for resource sharing.
• Three years later, Gigabit Ethernet (1000Base-T) was introduced, first using fiber optic cable and then twisted pair cable. This marks another tipping point for 802.3. In 2002, 10 Gbit/s drove Ethernet development, first over fiber, then twin axial, and finally an unshielded twisted pair. Eight years later, the IEEE allowed 10 Mbps lanes to be aggregated to achieve 40GbE and 100GbE speeds. 
• IEEE approved 25GbE in 2016. This has fueled demand from hyper-scale web companies. 25GbE was promised to be 2.5 times faster than 10GbE and cheaper than 40GbE. 25GbE uses fewer cables and power than 40GbE and has higher port density. This is because throughput is increased by increasing the capacity of one lane rather than aggregating many lanes with less capacity. In some cases, an upgrade to 25GbE allows data center operators to extend the life of their top-of-rack switches without completely rebuilding their cable architecture.
• In late 2017, the network industry embraced 200GbE and 400GbE. Both are based on a single lane of 50Gbps. Standardization groups are currently focused on 800 Gbps, 1 Tbps, and beyond. This is due to the surge in demand for higher bandwidth, especially from cloud providers and other hyper-scale data center operators. Ethernet is still under development.

OSI Model:

The OSI model’s data link layer and lower layers are included in Layer 2 and Layer 1 of the Ethernet standard, respectively. Ethernet is occasionally referred to as a link layer standard. The physical and data link layers of the OSI model contain entities that are all described by Ethernet standards. The IEEE standard contains certain additional sublayers that fit into the bottom two layers of the OSI model to help manage the details. This simply implies that the IEEE standard has some more detailed instructions than the OSI model.