1) A trademark for a LAN protocol.
2) A local area network first described by
Metcalfe &
Boggs of Xerox
PARC in 1976. Specified by DEC, Intel and XEROX (DIX) as
IEEE 802.3 and now recognised as the industry standard.
Data is broken into packets and each one is transmitted using the CSMA/CD algorithm until it arrives at the destination without colliding with any other packet. The first contention slot after a transmission is reserved for an acknowledge packet. A node is either transmitting or receiving at any instant. The bandwidth is about 10
Mbit/s. Disk-Ethernet-Disk transfer rate with
TCP/IP is typically 30
kilobyte per second.
Version 2 specifies that collision detect of the transceiver must be activated during the inter-packet gap and that when transmission finishes, the differential transmit lines are driven to 0V (
half step). It also specifies some network management functions such as reporting collisions, retries and deferrals.
Ethernet cables are classified as "XbaseY", e.g. 10base5, where X is the data rate in
Mbps, "base" means "baseband" (as opposed to radio frequency) and Y is the category of
cabling. The original cable was 10base5 ("full spec"), others are 10base2 ("thinnet") and 10baseT ("twisted pair") which is now (1998) very common. 100baseT ("Fast Ethernet") is also increasingly common.
Person 1: "What the heck, my Internet won't work!"
Person 2: "Dude, that's because your
ethernet cable is
unplugged!"
