IEEE 802.3
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free encyclopedia
IEEE 802.3 is a collection of IEEE standards defining
the physical
layer, and the media access control (MAC) sublayer of the data
link layer, of wired Ethernet. This is generally a LAN technology with some WAN
applications. Physical connections are made between nodes and/or infrastructure
devices (hubs,
switches,
routers) by
various types of copper or fiber cable.
802.3 is a technology that can
support the IEEE
802.1 network architecture.
The maximum packet size is 1518 bytes, although to
allow the Q-tag for Virtual LAN and priority data in 802.3ac it is extended to 1522
bytes. If the upper layer protocol submits a protocol data unit (PDU) less than 64 bytes, 802.3 will pad
the data field to achieve the minimum 64 bytes. The minimum Frame size will
then always be of 64 bytes.
Although it is not technically
correct, the terms packet and frame are often used
interchangeably. The ISO/IEC 8802-3 and ANSI/IEEE 802.3 standards refer to MAC
sub-layer frames consisting of the destination address, the source address,
length/type, data payload, and frame check sequence (FCS) fields. The
preamble and Start Frame Delimiter (SFD) are (usually)
together considered a header to the MAC frame. This header and the MAC frame
constitute a packet.
The original Ethernet is called Experimental
Ethernet today. It was developed by Robert
Metcalfe in 1972 (patented in 1978) and was based in part on the wireless ALOHAnet
protocol. The first Ethernet that was generally used outside Xerox was DIX Ethernet, followed by Ethernet II. IEEE
defines a 802.3 standard where the Type field is replaced by Length, and an
802.2 LLC header follows with the Type field. However, as DIX Ethernet was
derived from Experimental Ethernet, and as many standards have been developed
that are based on DIX Ethernet, the technical community has accepted the term
Ethernet for all of them. Therefore, the term Ethernet can be used to
name networks using any of the following standardized media and functions:
[edit] IEEE 802.3 Standards
|
Ethernet Standard |
Date |
Description |
|
Experimental |
1972 |
|
|
Ethernet II |
1982 |
10 Mbit/s (1.25 MB/s) over |
|
IEEE 802.3 |
1983 |
10BASE5 10 |
|
1985 |
10BASE2 10 |
|
|
1985 |
||
|
1985 |
10 Mbit/s (1.25 |
|
|
1987 |
FOIRL (Fiber-Optic |
|
|
1987 |
||
|
1990 |
10BASE-T 10 |
|
|
1993 |
10BASE-F 10 |
|
|
1995 |
100BASE-TX, |
|
|
1997 |
Full Duplex and flow control; also incorporates DIX |
|
|
1998 |
100BASE-T2 |
|
|
1998 |
1000BASE-X |
|
|
802.3-1998 |
1998 |
A revision of base |
|
1999 |
1000BASE-T |
|
|
1998 |
Max frame size |
|
|
2000 |
Link |
|
|
802.3-2002 |
2002 |
A revision of base |
|
2003 |
10 Gbit/s (1,250 MB/s) Ethernet over fiber; |
|
|
2003 |
||
|
2004 |
||
|
2004 |
10GBASE-CX4 |
|
|
802.3-2005 |
2005 |
A revision of base |
|
2006 |
10GBASE-T |
|
|
2007 |
Backplane |
|
|
2006 |
10GBASE-LRM |
|
|
Cancelled |
Congestion |
|
|
2006 |
Frame expansion |
|
|
~ Sep 2009[1] |
Power over Ethernet enhancements |
|
|
2006 |
Isolation |
|
|
~ Sep 2009[1] |
10 Gbit/s EPON |
|
|
2007 |
Fixed an equation in |
|
|
802.3-2008 |
2008 |
A revision of base |
|
~ Sep 2010[1] |
Energy Efficient |
|
|
~ Jun 2010[1] |
40 Gbit/s and |
|
|
802.3bb |
~ Autumn 2009[1] |
Increase Pause |
|
802.3bc |
~ Autumn 2009[1] |
Ethernet |
|
802.3bd |
~ 2011 |
Priority-based Flow |
|
802.3be |
~ 2010[1] |
Creates an IEEE |
What is defined in earlier IEEE
802.3 standards is often confused for what is used in practice: most network
frames you will find on an Ethernet will be DIX frames, since the Internet protocol suite will use this
format, with the type field set to the corresponding IETF protocol type. IEEE
802.3x-1997 allows the 16-bit field after the MAC addresses to be used as a
type field or a length field, so that DIX frames are also valid 802.3 frames in
802.3x-1997 and later versions of the IEEE 802.3 Ethernet standard.