The Fundamentals of an Ethernet LAN

Ethernet

Overview

Ethernet is a way of connecting computers together in a local area network or LAN. It has been the most widely used method of linking computers together in LANs since the 1990s. The basic idea of its design is that multiple computers have access to it and can send data at any time. There are different Ethernet standards. Today, Ethernet cables look like thick telephone cables. They connect to boxes called hubs or switches. Each cable runs from a computer's network interface card (NIC) to such a box. 

This cable is called 10BaseT or 100BaseT, or 1000BaseT Cable. Any device accessing a geographically localized network using a cable i.e., with a wired rather than wireless connection likely uses Ethernet whether in a home, school or office setting. From businesses to gamers, diverse end users depend on the benefits of Ethernet connectivity, including reliability and security.

Compared to wireless LAN technology, Ethernet is typically less vulnerable to disruptions whether from radio wave interference, physical barriers or bandwidth hogs. It can also offer a greater degree of network security and control than wireless technology, as devices must connect using physical cabling making it difficult for outsiders to access network data or hijack bandwidth for unsanctioned devices.

All cable types:

10Base2 and 10Base5

These coaxial cables are like those used in television, but thinner. They are also called "thinnet" or "coax". Each computer has a "T" plugged into it, and cables plug into each side of the "T". Sometimes, instead of a "T", a vampire tap is used. It supports 10MBits per second transfer speed. It was the first to be adopted and became rare during the 21st century.

10BaseT 

Cables look like thick phone cables, but with 8 copper wires instead of 2 or 4, and they go from each computer' to a Hub or a Switch. Supported speed is 10 MBit/second.

10BaseF

Same as 10BaseT, but cables transmit light pulses, instead of electrical signals.

100BaseT

Cables look the same as 10BaseT but can run at up to 100 MBits per second

1000BaseT

Cables look the same as 10BaseT but can run at up to 1GBit (1000MBit) per second.

How Ethernet works:

The Institute of Electrical and Electronics Engineers Inc. (IEEE) specifies in the family of standards called IEEE 802.3 that the Ethernet protocol touches both Layer 1 the physical layer and Layer 2 the data link layer on the OSI network protocol model. Ethernet defines two units of transmission: packet and frame. Engineers at Xerox first developed Ethernet in the 1970s. Ethernet initially ran over coaxial cables, while a typical Ethernet LAN today uses special grades of twisted pair cables or fiber optic cabling.

Early Ethernet connected multiple devices into network segments through hubs Layer 1 device responsible for transporting network data using either a daisy chain or star topology. If two devices that share a hub try to transmit data at the same time, however, 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, which allows devices to check whether a given line is in use before initiating new transmissions. 

Later, Ethernet hubs largely gave way to network switches, their more sophisticated and modern counterparts. Because a hub cannot discriminate between points on a network segment, it can't 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 the 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 improving security and efficiency.