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.