http://standards.ieee.org/getieee802/802.3.html

http://standards.ieee.org/getieee802/download/802.3-2005_section1.pdf
http://standards.ieee.org/getieee802/download/802.3-2005_section2.pdf
http://standards.ieee.org/getieee802/download/802.3-2005_section3.pdf
http://standards.ieee.org/getieee802/download/802.3-2005_section4.pdf
http://standards.ieee.org/getieee802/download/802.3-2005_section5.pdf

