Ethernet is a local-area network (LAN) protocol. Recall that a protocol is a set of rules followed by all of the computers in a given network so that data being transferred do not collide into each other. Ethernet was developed in the 1970s by Xerox Corporation. Then in about 1979, three companies, Xerox, Digital Equipment Corporation, and Intel Corporation, got together to try and standardize this new system. The result of this attempt is called DIX (Digital, Intel, Xerox). It is what is commonly referred to as "Ethernet." However, in 1983, a new standard for Ethernet was created-the Institute of Electrical and Electronic Engineers (IEEE) released the Ethernet standard called IEEE 802.3.
Ever since its introduction to the world, Ethernet has become increasingly popular. It is now one of the most common LAN protocols used throughout the world!
As you know, networks can connect all sorts of computers and other devices. To connect these devices (called nodes), Ethernets use some sort of medium. The most common medium used to connect devices on a network is a twisted pair of fiber optic cabling. The nodes communicate in what is called a frame. Frames are short messages, and can be compared to sentences in the human language.
Well, with all the nodes connected to a network, that network has quite a
job regulating the messages and making sure they don't collide with another.
How Ethernet does this can be described in the acronym CSMA/CD. CSMA/CD stands
for Carrier Sense Multiple Access with Collision Detection. This might seem
like a complex concept, but it really isn't.
First, say a computer connected to the network wants to transfer information to another computer. Before it does so, it checks to see if there is any other data or information being transferred. If not, it will wait until the medium is free. If so, the computer will transmit the data. When data is transmitted, all of the devices connected to the computer can hear the transmission.
Despite the precautions that are taken to make sure that no two computers are trying to transfer data at the same time, sometimes collisions still occur. Collisions are when two devices on a network try to transmit information at the same time. When this happens, the information being transmitted is sent back to the device it came from. Then, that device will wait for a random amount of time, before sending the information again.
Recently, newer versions of Ethernet have been developed. They are much faster
than the original Ethernets. One of the newest versions, FastEthernet, can
transfer data up to 100 megabits (100 million bits) per second! There is also
the Gigabit Ethernet, which transfers 1 gigabit (1 billion bits) of data per
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