Ethernet Tutorial 2

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1.  Ethernet Frames Format

Ethernet Frames

Field	DIX Frame	IEEE 802.3 Frame
Preamble	8 bytes	7 bytes
Start Frame Delimiter		1 bytes
Destination Address	6 bytes	6 bytes
Source Address	6 bytes	6 bytes
Length		2 bytes
Type	2 bytes
LLC		Yes
Data	1500 bytes	Yes
Pad		Yes
CRC/FCS	4 bytes	4 bytes
Total	1518 bytes	1518bytes

Note: 100/1000Mbs Ethernet Systems do not need preamble or start frame delimiter fields.

Ethernet Tutorial 1

One Ethernet tutorial I like very much is from Fujisu since it includes all the basics of Ethernet technologies.  The following is my reading note, and you could read the original article by clicking here. You could also
check this link from England.

1. Ethernet History
Robert Metcalfe from Xerox described his invention Ethernet in 1973. He modeled Ethernet after the Aloha network developed at University of Hawaii in the 1960s and the initial Ethernet systems ran at 2.94Mb/s. Ethernet patent was awarded to Metcalfe and his co-workers, but wholly-owned by Xerox.
2. Ethernet Standards
In 1980, DEC, Intel and Xerox (DIX) issued a DIX Ethernet standard for 10Mb/s Ethernet systems.  In 1985, IEEE  published the open Ethernet standard IEEE 802.3. Why 802? It is because work started in February 1980. For all the later Ethernet standard,  people could refer Wikipedia link 802.3 .
3.  Ethernet Technologies

• Fast Ethernet 

         In 1995, IEEE 802.3u defines 100Mb/s Ethernet over wire or fiber-optic cable. Speed could be auto-negotiated between equipments to choose 10Mb/s or 100Mb/s.