Ethernet definition – Freescale Semiconductor TWR-MCF52259-Ethenet User Manual

Page 22

Freescale Semiconductor Confidential and Proprietary Information. Freescale™ and the Freescale logo are trademarks
of Freescale Semiconductor, Inc. All other product or service names are the property of their respective owners. © Freescale Semiconductor, Inc. 2006.

Ethernet Definition…

Ethernet -

http://dictionary.reference.com/search?q=Ethernet

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

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