tailieunhanh - Ethernet Networking- P2

Ethernet Networking- P2:One of the biggest problems when discussing networking is knowing where to start. The subject of computer networks is one of those areas for which you have to "know everything to do anything." Usually, the easiest way to ease into the topic is to begin with some basic networking terminology and then look at exactly what it means when we use the word Ethernet. | 18 Introduction The number of bits that can travel together at the same time represents the bandwidth of the transmission medium. If we can increase the bandwidth we can increase the throughput without changing the maximum physical transfer speed of bits down the wire. Fiber optic cabling for example is very fast not only because each bit can travel at the speed of light but because so many tiny glass fibers can be bound together into a single cable to provide a high bandwidth. Ethernet Standards The types of Ethernet about which you have just read are defined in a set of standards prepared by the Institute of Electrical and Electronic Engineers IEEE . The committee in charge of the standards for LANs is known as IEEE LAN 802 and the group within it that handles media access controls standards as . Each standard describes a method for media access control and the transmission media that should be supported. Note Although the name of the IEEE may not suggest that the organization has anything to do with computing keep in mind that the IEEE predates computers. It has evolved to encompass a wide range of computing standards and applications. Although in most cases you won t be concerned directly with the specifications themselves and the rather strange numbering scheme that goes along with them you may find that equipment and cable vendors use the standard numbers to identify the type of Ethernet for which a product is appropriate. You should therefore at least be familiar with the type of Ethernet each standard represents. This book identifies the standards that accompany each type of Ethernet cabling as we explore hardware details in the following chapters. A Bit of Ethernet History 19 A Bit of Ethernet History Originally Ethernet was the brainchild of one person Robert Metcalfe. In the early 1970s while working at Xerox PARC on the office of the future project Metcalfe was intrigued by a radio network in Hawaii known as AlohaNet. One problem faced by .