From LQWiki
Ethernet is an open standard networking protocol widely used across the world it is described by the IEEE802.3 standard. In the OSI Model, the ethernet protocol is a Layer 2 (Data-link) protocol, although the individual ethernet specifications also specify Layer 1 (Physical) protocol. Ethernet is an example of "best effort" protocol, in that there is no theoretical guarantee that a given packet will ever get to its destination. However, ethernet is extremely flexible and powerful, and is being used in virtually every networking application.
Contents |
Features
- CSMA/CD (Carrier Sense Multiple Acces/Collision detection): This is how Ethernet manages which host accesses the network. Before transmitting any data a host will check if any data is currently being sent along the medium, if not it will transmit. This method can result in data being transmitted at once by 2 hosts, causing a collision of the data (hence corruption) when this happens ethernet will detect the collision and every host will stop transmitting for a random period of time. Collisions affect the total throughput and in ethernet the throughput lost by collisions can be around 40% of bandwidth.
- Can travel across any medium, typically copper cabling (for example, CAT5), optical cables or wirelessly. In fact ethernet is designed to travel across any medium which has been demonstrated by CPIP (Carrier Pigeon Internet Protocol(though not technically ethernet).
History
Ethernet was originally developed at PARC, and had some indirect influence on the development of TCP/IP. The PARC engineers were forbidden from giving the TCP/IP development team any information about Ethernet (which was still a trade secret at the time). However, PARC was one of the main ARPANET sites at the time (TCP/IP was developed for the ARPANET), and many of PARC's staff came from the original ARPANET project. Because of this, the PARC hackers saw it as their duty to assist. (See hacker ethic.) They realized that while they were forbidden to hand out answers, they were not forbidden to ask really involved and informed questions, based on their experience with similar problems in the development of Ethernet.
Ethernet itself was inspired by ALOHANET.
See also
References
- Dealers of Lightning : Xerox PARC and the Dawn of the Computer Age, by Michael A. Hiltzik (ISBN 0887309895) (paragraph on PARC's influence on TCP/IP)
This article is a stub and needs to be finished. Plunge forward and help it grow!
This page is available under a