What is Ethernet? Definitions, Usage, and Components

In order to communicate with one another, devices in a network need to be connected. This is typically accomplished using WiFi (wireless connection) or Ethernet (wires that are plugged into a computer). 

In this blog, you'll learn more about what Ethernet is and how it provides a fast, reliable, and secure connection to facilitate rapid data transfer over networks and between devices.

What is Ethernet?

Ethernet is the traditional technology for connecting devices in a wired local area network (LAN), or wide area network.

A form of I/O (inout/output), it enables devices to communicate with one another via a protocol, a set of rules or common network language. 

Ethernet describes how network devices format and transmit data so that other devices on the same LAN or campus network can recognize, receive, and process the information.

An Ethernet cable is a physical object that encases the wiring over which data travels. Ethernet ports, or local area network (LAN) ports, are found on the back of a computer or side of a laptop. 

Connected devices that use cables to access a geographically localized network likely use Ethernet, which, in general, is reliable and secure. 

Ethernet was invented in 1973 by a team at Xerox Corporation's Palo Alto Research Center (Xerox PARC) in California. 

Compared to wireless LAN (WLAN) technology, Ethernet is typically less vulnerable to disruptions, and it can also offer a greater degree of network security and control. 

This is because devices must connect using physical cabling, making it difficult for outsiders to access network data or hijack bandwidth for unsanctioned devices. 

Why is Ethernet used?

Ethernet is used to connect devices in a network, and it is widely used due to its high speed, security, and reliability.

Ethernet became popular due to its relatively low cost when compared to the competing technology of the time, like IBM's token ring. Ethernet is also backward compatible, meaning it can successfully use interfaces and data from earlier versions of a system or with other systems.

As network technology advanced, however, Ethernet's ability to evolve and deliver higher levels of performance ensured its sustained popularity. 

Originally, Ethernet supported up to 10 megabits per second (Mbps). It then increased to 100 Mbps in the mid 1990s.

The Institute of Electrical and Electronics Engineers (IEEE) continues to deliver increased performance with successive updates. Currently, Ethernet can support up to 400 gigabits per second (Gbps). 

Components and operation

Let's take a look at the hardware that comprises Ethernet, and then how Ethernet actually works. 

Ethernet hardware 

There are three main pieces of Ethernet hardware: Ethernet cards, or adapters, Ethernet cables, and Ethernet routers, or hubs. 

The Ethernet card is the component that is actually installed in each computer that connects to the network via an Ethernet cable; it is the hardware that the computer uses to transmit and receive data packets across the network and the Internet. 

Ethernet cables contain several wires which allow the transfer of data in both directions to and from the computer. They can come in a number of styles, the most common being Category 5 (Cat5) and Category 6 (Cat6) cables. 

The Ethernet hub is used by the network to direct the intra-computer data across the network so that the correct computers can share it and can also serve as a link to the Internet. 

How Ethernet actually works

The IEEE specifies that the Ethernet protocol touches both Layer 1 (physical layer) and Layer 2 (data link layer). 

Ethernet defines two units of transmission: packet and frame. The frame includes the payload of data being transmitted as well as the following: 

1. The physical media access control (MAC) addresses of both the sender and the receiver
2. Virtual LAN (VLAN) tagging and quality of service (QoS) information
3. Error correction information to detect transmission problems

Each frame is wrapped in a packet that contains several bytes of information to establish the connection and mark where the frame starts. 

Initially, Ethernet ran over coaxial cables. Early Ethernet connected multiple devices into network segments through hubs. Currently, a typical Ethernet LAN uses special grades of twisted-pair cables or fiber optic cabling. (More on this later.) 

There were, however, some problems that persisted. If two devices that share a hub try to transmit data at the same time, the packets can collide and create connectivity problems.

To alleviate these digital traffic jams, the IEEE developed the Carrier Sense Multiple Access with Collision Detection (CSMA/CD) protocol. This protocol enables devices to check whether a given line is in use before initiating new transmissions. 

Later, Ethernet hubs gave way to network watches. Because a hub cannot discriminate between points on a network segment, it cannot send data directly from point A to point B.

Instead, whenever a network device sends a transmission via an input port, the hub copies the data and distributes it to all available output ports. 

In contrast, a switch intelligently sends any given port only the traffic intended for its devices rather than copies of any and all the transmissions on the network segment, thus improving security and efficiency. 

Like with other network types, involved computers must include NIC cards, circuit boards that are installed on a computer to connect to the network and Ethernet cable. 

Types of Ethernet cables

There are three types of cables commonly used for Ethernet cabling: coaxial cables, twisted pair cables, and fiber-optic cables. 

Currently, the twisted pair cables are the most popular, but fiber optic cable use is increasing, especially in high-performance networks. Coaxial cabling is generally used for cable Internet access.

Coaxial cabling

A coaxial cable has an inner conductor that runs down the middle of the cable. The conductor is surrounded by a layer of insulation which is then surrounded by another conducting shield, which makes this types of cabling resistant to outside interference. 

This type of cabling comes in two types: thinnet and thicknet. Both types have maximum transmission speeds of 10 Mbps.

Coaxial cabling was previously used in computer networks, but today they are largely replaced by twisted-pair cabling. 

Twisted-pair cabling

A twisted pair cable has four pairs of wires. These wires are twisted around each other to reduce crosstalk and outside interference. This type of cabling is common in current LANs. 

Twisted-pair cabling can be used for telephone and network cabling. It comes in two versions: Unshielded Twisted-Pair (UTP) and Shielded Twisted-Pair (STP). The difference between the two is that an STP cable has an additional layer of insulation that protects data from outside interferences. 

Fiber optic cabling

Fiber optic cables use optical fibers to transmit data in the form of light signals. The cables have strands of glass surrounded by a cladding material. 

This type of cabling can support greater cable lengths than any other cabling type. The cables are also immune to electromagnetic interference. As you can see, this cabling method has many advantages over other methods, but it is much more expensive. 

There are two types of fiber-optic cables:

1. Single-mode fiber (SMF): This uses only a single ray of light to carry data and is used for larger distances. 
2. Multi-mode fiber (MMF): This uses multiple rays of light to carry data, and it is less expensive than SMF. 

Advantages and disadvantages of Ethernet

Ethernet has many benefits, but it also has many drawbacks. Let's take a look at each. 

Advantages of Ethernet

1. Relatively low cost 
2. Backward compatibility
3. Generally resistant to noise 
4. Good data transfer quality 
5. Speed
6. Reliability
7. Data security

Disadvantages of Ethernet 

1. Intended for smaller, shorter distance networks
2. Limited mobility 
3. Use of longer cables can create crosstalk 
4. Does not work well with real-time interactive applications
5. Speeds decrease with increased traffic 
6. Receivers do not acknowledge the reception of data packets 
7. Troubleshooting is hard when trying to trace which specific cable or node is causing the issue

Ethernet and Trenton Systems

At Trenton, our USA-made, high-performance computing solutions support high-speed Ethernet and advanced network capabilities to quickly send critical information between data communication equipment (DCE).

Whether in the command room, in an unarmed vehicle, or in the field, Ethernet delivers the enhanced connectivity required by a wide variety of modern military operations like electronic warfare, C6ISR, and signal intelligence. 

Our 1U BAM FM, for example, supports 100GB/40GB/25GB/10GB/1GB Ethernet with IPMI to increase data transfer rates and connectivity between devices to deliver actionable insights in real-time. 

Other COTS (commercial-off-the-shelf) hardware communicate with one another via Ethernet, and there is no customization needed for most military applications, reducing time to market and expenditures on customized solutions for a diverse array of military requirements. 

With these high-speed computing capabilities, our systems ensure that data is sent between devices and over networks in the blink of an eye, providing the information necessary for improved decision-making capabilities and mission success across the modern battlespace. 

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