IEEE 802.3 Standards

IEEE 802.3

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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
Ethernet
 1972
 2.94 Mbit/s (367 kB/s) over coaxial cable (coax) cable bus
 
Ethernet II
(DIX v2.0)
 1982
 10 Mbit/s (1.25 MB/s) over thin coax (thinnet) - Frames have a Type field. This frame format is used on all forms of Ethernet by protocols in the Internet protocol suite.
 
IEEE 802.3
 1983
 10BASE5 10 Mbit/s (1.25 MB/s) over thick coax — same as DIX except Type field is replaced by Length, and an 802.2 LLC header follows the 802.3 header
 
802.3a
 1985
 10BASE2 10 Mbit/s (1.25 MB/s) over thin Coax (thinnet or cheapernet)
 
802.3b
 1985
 10BROAD36
 
802.3c
 1985
 10 Mbit/s (1.25 MB/s) repeater specs
 
802.3d
 1987
 FOIRL (Fiber-Optic Inter-Repeater Link)
 
802.3e
 1987
 1BASE5 or StarLAN
 
802.3i
 1990
 10BASE-T 10 Mbit/s (1.25 MB/s) over twisted pair
 
802.3j
 1993
 10BASE-F 10 Mbit/s (1.25 MB/s) over Fiber-Optic
 
802.3u
 1995
 100BASE-TX, 100BASE-T4, 100BASE-FX Fast Ethernet at 100 Mbit/s (12.5 MB/s) w/autonegotiation
 
802.3x
 1997
 Full Duplex and flow control; also incorporates DIX framing, so there's no longer a DIX/802.3 split
 
802.3y
 1998
 100BASE-T2 100 Mbit/s (12.5 MB/s) over low quality twisted pair
 
802.3z
 1998
 1000BASE-X Gbit/s Ethernet over Fiber-Optic at 1 Gbit/s (125 MB/s)
 
802.3-1998
 1998
 A revision of base standard incorporating the above amendments and errata
 
802.3ab
 1999
 1000BASE-T Gbit/s Ethernet over twisted pair at 1 Gbit/s (125 MB/s)
 
802.3ac
 1998
 Max frame size extended to 1522 bytes (to allow "Q-tag") The Q-tag includes 802.1Q VLAN information and 802.1p priority information.
 
802.3ad
 2000
 Link aggregation for parallel links, since moved to IEEE 802.1AX
 
802.3-2002
 2002
 A revision of base standard incorporating the three prior amendments and errata
 
802.3ae
 2003
 10 Gbit/s (1,250 MB/s) Ethernet over fiber; 10GBASE-SR, 10GBASE-LR, 10GBASE-ER, 10GBASE-SW, 10GBASE-LW, 10GBASE-EW
 
802.3af
 2003
 Power over Ethernet
 
802.3ah
 2004
 Ethernet in the First Mile
 
802.3ak
 2004
 10GBASE-CX4 10 Gbit/s (1,250 MB/s) Ethernet over twin-axial cable
 
802.3-2005
 2005
 A revision of base standard incorporating the four prior amendments and errata.
 
802.3an
 2006
 10GBASE-T 10 Gbit/s (1,250 MB/s) Ethernet over unshielded twisted pair(UTP)
 
802.3ap
 2007
 Backplane Ethernet (1 and 10 Gbit/s (125 and 1,250 MB/s) over printed circuit boards)
 
802.3aq
 2006
 10GBASE-LRM 10 Gbit/s (1,250 MB/s) Ethernet over multimode fiber
 
802.3ar
 Cancelled
 Congestion management
 
802.3as
 2006
 Frame expansion
 
802.3at
 ~ Sep 2009[1]
 Power over Ethernet enhancements
 
802.3au
 2006
 Isolation requirements for Power Over Ethernet (802.3-2005/Cor 1)
 
802.3av
 ~ Sep 2009[1]
 10 Gbit/s EPON
 
802.3aw
 2007
 Fixed an equation in the publication of 10GBASE-T (released as 802.3-2005/Cor 2)
 
802.3-2008
 2008
 A revision of base standard incorporating the 802.3an/ap/aq/as amendments, two corrigenda and errata. Link aggregation was moved to 802.1AX.
 
802.3az
 ~ Sep 2010[1]
 Energy Efficient Ethernet
 
802.3ba
 ~ Jun 2010[1]
 40 Gbit/s and 100 Gbit/s Ethernet. 40 Gbit/s over 1m backplane, 10m Cu cable assembly (4x25 Gbit or 10x10 Gbit lanes) and 100 m of MMF and 100 Gbit/s up to 10 m or Cu cable assembly, 100 m of MMF or 40 km of SMF respectively
 
802.3bb
 ~ Autumn 2009[1]
 Increase Pause Reaction Delay timings which are insufficient for 10G/sec (to be released as 802.3-2008/Cor 1)
 
802.3bc
 ~ Autumn 2009[1]
 Ethernet Organizationally Specific type, length, values (TLVs). Move and update ethernet related TLVs currently specified in IEEE 802.1AB.
 
802.3bd
 ~ 2011
 Priority-based Flow Control. A amendment by the IEEE 802.1 Data Center Bridging Task Group to develop an amendment to IEEE Std 802.3 to add a MAC Control Frame to support IEEE 802.1Qbb Priority-based Flow Control.
 
802.3be
 ~ 2010[1]
 Creates an IEEE 802.3.1 MIB definitions for Ethernet that consolidates the ethernet related MIBs present in Annex 30A&B, various IETF RFCs, and 802.1AB annex F into one master document with a machine readable extract.
 

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.

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