Though some people call a certain type of cabling “Ethernet”, it’s really a set of rules or protocols that explain how to send signals over many different kinds of cables. We talked about twisted-pair cabling in a previous post, and that is just one of the cables.
Ethernet was invented and then further developed by a team of engineers led by Robert Metcalf at the Xerox PARC (short for Palo Alto Research Center) in 1972. The original, Ethernet I, ran at 2.94 Mbps, supported a cable distance up to 1 km, and connected up to 256 devices. In 1979, the team, with help from Digital Equipment Corporation and Intel, rolled out Ethernet II which is also known as DIX Ethernet.
In 1983, the IEEE approved an official set of rules for a very similar process from its 802.3 Working Group. For years there were two sets of rules: The official standard 802.3 and the de facto standard Ethernet ii.
The IEEE created names for the different types of 802.3 that focus on speed, signaling method, and cabling. Their first was 10Base-5, the yellow cable and its transceivers and connecting cables. That meant 10 Mbps baseband signaling over a thick RG-8 coax cable that could be up to 500 meters long with 100 devices on each segment of cable as long as they were at least 2.5 meters apart. It’s also known as ThickNet. 10Base-2, also called ThinNet or CheaperNet, followed 10Base-5. Other names include:
|10Base-2||50 Ohm coaxial cable||185 meters|
|100Base-5||50 Ohm RG-8/U coaxial cable||500 meters|
|10Base-F||Two strands of multi-mode fiber||1 to 2 kilometers|
|100Base-FX||Two strands of multi-mode fiber||2 milometers|
|100Base-SX||Two strands of multi-mode fiber||550 meters|
|100Base-BX||One strand of single-mode fiber||10, 20, or 40 kilometers|
|100Base-LX10||Two strands of single-mode fiber||10 kilometers|
|1000Base-CX||Twinaxial cabling||25 meters|
|1000Base-SX||Multi-mode fiber||220 meters|
|1000Base-LX||Multi-mode fiber||550 meters|
|1000Base-LX||Single-mode fiber||5 kilometers|
|1000Base-LX10||Single-mode fiber||10 kilometers|
|1000Base-EX||Single-mode fiber||~40 kilometers|
|1000Base-ZX||Single-mode fiber||~70 kilometers|
|1000Base-BX10||Single-mode fiber||10 kilometers|
|1000Base-T||Twisted-pair cabling||100 meters|
|1000Base-TX||Twisted-pair cabling||100 meters|
|10GBase-SR||Multi-mode fiber||33 to 400 meters|
|10GBase-LR||Single-mode fiber||10 to 25 kilometers|
|10GBase-ER||Single-mode fiber||30 kilometers|
|10GBase-T||Unshielded or shielded twisted pair||100 meters|
|40GBase-SR4||Multi-mode fiber||100 to 125 meters|
|40GBase-LR4||Single-mode fiber||10 kilometers|
|100GBASE-SR10||Multi-mode fiber||100 to 125 meters|
|100GBASE-LR4||Single-mode fiber||10 kilometers|
|100GBASE-ER4||Single-mode fiber||40 kilometers|
Both 802.3 and Ethernet II were based on CSMA/CD technology. That means the sending Ethernet card recognizes it is attached to an active interface (Carrier Sense). It has “heard” traffic from other devices on that interface (Multiple Access). It can recognize when two systems on the network with it have transmitted at the same time (Collision Detection). Now that twisted-pair and switches have removed collisions, CSMA/CD is now out of use.