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This illustrates a common problem: One way you can do that is to insist on complete information from the vendor as to what standard the product complies with. It may not be a bad thing if the product is built to a draft version of a new supplement.
Draft versions of the supplements can be substantially complete yet still take months to be voted on by the various IEEE committees.
When buying pre-standard equipment built to a draft of the specification, you need to ensure that the draft in question is sufficiently well along in the standards process that no major changes will be made.
One solution to this is to get a written guarantee from the vendor that the equipment you purchase will be upgraded to meet the final published form of the standard. Note that the IEEE forbids vendors to claim or advertise that a product is compliant with an unapproved draft. The specifications for the original DIX Ethernet standard were developed by the three companies involved and were intended to describe the Ethernet system—and only the Ethernet system.
The efforts aimed at creating a worldwide system of open standards had only just begun. Consequently, the IEEE made several technical changes required for inclusion in the worldwide standardization effort.
This model was developed in by the International Organization for Standardization, whose initials derived from its French name are ISO. Headquartered in Geneva, Switzerland, the ISO is responsible for setting open, vendor-neutral standards and specifications for items of technical importance.
The ISO developed the OSI reference model to provide a common organizational scheme for network standardization efforts with perhaps an additional goal of keeping us all confused with reversible acronyms.
What follows is a quick, and necessarily incomplete, introduction to the subject of network models and international standardization efforts. The Seven Layers of OSI The OSI reference model is a method of describing how the interlocking sets of networking hardware and software can be organized to work together in the networking world.
In effect, the OSI model provides a way to arbitrarily divide the task of networking into separate chunks, which are then subjected to the formal process of standardization. To do this, the OSI reference model describes seven layers of networking functions, as illustrated in Figure 1.
The lower layers cover the standards that describe how a LAN system moves bits around. The higher layers deal with more abstract notions, such as the reliability of data transmission and how data is represented to the user.
The layers of interest for Ethernet are the lower two layers of the OSI model. The OSI seven layer model In brief, the OSI reference model includes the following seven layers, starting at the bottom and working our way to the topmost layer: Physical layer Standardizes the electrical, mechanical, and functional control of data circuits that connect to physical media.
Data link layer Establishes communication from station to station across a single link.
This is the layer that transmits and receives frames, recognizes link addresses, etc. The part of the standard that describes the Ethernet frame format and MAC protocol belongs to this layer. Network layer Establishes communication from station to station across an internetwork, which is composed of a number of data links.
This layer provides a level of independence from the lower two layers by establishing higher level functions and procedures for exchanging data between computers across multiple links.
Standards at this layer of the model describe portions of the high-level network protocols that are carried over an Ethernet in the data field of the Ethernet frame.
Protocols at this layer of the OSI model and above are independent of the Ethernet standard. Transport layer Provides reliable end-to-end error recovery mechanisms and flow control in the higher level networking software.
Session layer Provides mechanisms for establishing reliable communications between cooperating applications. Presentation layer Provides mechanisms for dealing with data representation in applications.
Application layer Provides mechanisms to support end-user applications such as mail, file transfer, etc.
The Ethernet standards describe a number of entities that all fit within the data link and physical layers of the OSI model. While at first glance these extra layers might seem to be outside the OSI reference model, the OSI model is not meant to rigidly dictate the structure of network standards.
Instead, the OSI model is an organizational and explanatory tool; sublayers can be added to deal with the complexity of a given standard. Within these major sublayers there are even further sublayers defined for additional MAC functions, new physical signaling standards, and so on.
The MAC layer defines the protocol used to arbitrate access to the Ethernet system. Both of these systems are described in detail in Chapter 3.
Each of the sublayers is used to help organize the Ethernet specifications around specific functions that must be achieved to make the Ethernet system work. Understanding these sublayers can also help us understand the scope of the various standards involved.
As such, it is functionally independent of the various physical layer media specifications and does not change, no matter which physical media variety may be in use. To help make this clearer, the Ethernet-specific portions of the standard in Figure 1. Levels of Compliance In developing a technical standard, the IEEE is careful to include only those items whose behavior must be carefully specified to make the system work.
Therefore, all Ethernet interfaces that operate in the original half-duplex mode described in Chapter 3 must comply fully with the MAC protocol specifications in the standard to perform the functions identically.Ethernet: Ethernet, computer networking technology used in local area networks (LANs).
Ethernet was created in by a team at the Xerox Corporation’s Palo Alto Research Center (Xerox PARC) in California. The team, led by American electrical engineer Robert Metcalfe, sought to create a . Xerox has a rich history of innovation. As the inventors of Ethernet over 30 years ago, we helped build the foundation for today's Internet.
In fact, not known to many, the Ethernet's first commercialization was as a communication bus in our production publishing systems in the early s. Xerox: Xerox, major American corporation that was a pioneer of office technology, notably being the first to manufacture xerographic plain-paper copiers.
Headquarters are in Norwalk, Connecticut.
Learn more about the corporation’s history, innovations, and products. Then in , Xerox invented the prototype of the world's first personal computer, the Alto, with innovations including the first what-you-see-is-what-you-get editor, the first commercial use of a mouse, a graphical user interface and bit-mapped display.
May 28, · Metcalfe, in collaboration with David Boggs, invented and developed the Ethernet local-area network (LAN) and its system of packet protocols, which have proliferated and evolved to . The expensive Xerox workstations could not compete against the cheaper GUI-based workstations that arose in the wake of the first Macintosh, and Xerox eventually quit the workstation market for good.
Source code release. On October 21, , Xerox Alto's source code and other resources were released from the Computer History Museum.