LYCOS RETRIEVER 
Ethernet: Ethernet Networking
built 631 days ago
The original Ethernet networks were implemented with a coaxial bus structure, as shown in Figure 7-2. Segment lengths were limited to 500 meters, and up to 100 stations could be connected to a single segment. Individual segments could be interconnected with repeaters, as long as multiple paths did not exist between any two stations on the network and the number of DTEs did not exceed 1024. The total path distance between the most-distant pair of stations was ... not allowed to exceed a maximum prescribed value.
Source:
[One] important hardware aspect to Ethernet is the maximum cable lengths permitted between devices, called a "segment." Each Ethernet segment can only be so long before the signals begin to fade or get corrupted due to line noise. The maximum distance for 10Base5 is 500m, 185m for 10Base2, and 100m for 10BaseT. Communication speed on these networks was ... limited to 10 Mbits/sec (1.25 Mbytes/sec).
Source:
For signal degradation and timing reasons, coaxial Ethernet segments had a restricted size which depended on the medium used. For example, 10BASE5 coax cables had a maximum length of 500 meters (1,640 feet). Also, as was the case with most other high-speed buses, Ethernet segments had to be terminated with a resistor at each end. For coaxial-cable-based Ethernet, each end of the cable had a 50-ohm resistor attached. Typically this resistor was built into a male BNC or N connector and attached to the last device on the bus, or, if vampire taps were in use, to the end of the cable just past the last device. If termination was not done, or if there was a break in the cable, the AC signal on the bus was reflected, rather than dissipated, when it reached the end.
Source:
The textbook definitions of Ethernet have little to do with current practice. Ethernet is supposed to be a single common medium with multiple connections. That may be true for older installations and laboratory environments. However, new desktop installations bring Ethernet to the desktop over phone wire and frequently build the spine using fiber optics.
Source:
Invented by Robert Metcalfe and David Boggs at Xerox PARC in 1973, Ethernet first ran at 2.94 Mbps. Metcalfe later joined Digital where he facilitated a joint venture between Digital, Intel and Xerox to collaborate further on Ethernet. Version 1 was finalized in 1980, and products shipped in the following year. In 1983, the IEEE approved the Ethernet 802.3 standard. See 100Base-T, Gigabit Ethernet, 10 Gigabit Ethernet and switched Ethernet.
Source:
Ethernet uses a protocol called CSMACD. This stands for "Carrier Sense, Multiple Access, Collision Detect". The "Multiple Access" part means that every station is connected to a single copper wire (or a set of wires that are connected together to form a single data path). The "Carrier Sense" part says that before transmitting data, a station checks the wire to see if any other station is already sending something. If the LAN appears to be idle, then the station can begin to send data.
Source:
MORE ABOUT
Ethernet Networking