From a326250da0625c5ab6dfa8ebb56f390d22cd21f5 Mon Sep 17 00:00:00 2001 From: bnewbold Date: Sun, 27 May 2007 04:32:28 -0400 Subject: added ethernet, g's r, and books directory --- Ethernet | 49 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 49 insertions(+) create mode 100644 Ethernet (limited to 'Ethernet') diff --git a/Ethernet b/Ethernet new file mode 100644 index 0000000..6b4be44 --- /dev/null +++ b/Ethernet @@ -0,0 +1,49 @@ +======== +Ethernet +======== + +.. warning:: Under progress! + +History +======= +Bob Metcalfe first described the ethernet system in a memo while working at +the Xerox Palo Alto Research Center in 1973 ([oreilly]_). It was based on +the earlier *Aloha* system developed by Norman Abramson at the University of +Hawaii. *Aloha* was a radio network for inter-island communications. + +Structure +========= + +Data Frames +~~~~~~~~~~~ +The frame format is the same for ethernet systems of any speed. + +==================== =========== +Section Size (bits) +==================== =========== +Preamble 64 +Destination Address 48 +Source Address 48 +Type Length 16 +Data 46 to 1500 +Checksum 32 +==================== =========== + +.. topic:: Preamble + + The preamble originally served as a "warm up" period for hardware to + stabilize and prepare for the rest of the frame. + +.. topic:: Source and Destination addresses + + Manufacturers are given a 24 bit id (first half), and are expected to + ensure the uniqueness of the second half of each device's address. + + The IEEE-SA (Standards Association) delegates addresses. + +.. topic:: Checksum + + The checksum (or Frame Check Sequence) is a Cyclic Redundancy Checksum. + +.. [oreilly] `Ethernet: The Definitive Guide`:title:, by Charles Spurgeon. + O'Reilly, 2000 -- cgit v1.2.3