IEEE 802.3 Standards

IEEE 802.3

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IEEE 802.3 is a collection of IEEE standards definingthe physicallayer, and the media access control (MAC) sublayer of the datalink layer, of wired Ethernet. This is generally a LAN technology with some WANapplications. Physical connections are made between nodes and/or infrastructuredevices (hubs,switches,routers) byvarious types of copper or fiber cable.

802.3 is a technology that cansupport the IEEE802.1 network architecture.

The maximum packet size is 1518 bytes, although toallow the Q-tag for Virtual LAN and priority data in 802.3ac it is extended to 1522bytes. If the upper layer protocol submits a protocol data unit (PDU) less than 64 bytes, 802.3 will padthe data field to achieve the minimum 64 bytes. The minimum Frame size willthen always be of 64 bytes.

Although it is not technicallycorrect, the terms packet and frame are often usedinterchangeably. The ISO/IEC 8802-3 and ANSI/IEEE 802.3 standards refer to MACsub-layer frames consisting of the destination address, the source address,length/type, data payload, and frame check sequence (FCS) fields. Thepreamble and Start Frame Delimiter (SFD) are (usually)together considered a header to the MAC frame. This header and the MAC frameconstitute a packet.

The original Ethernet is called ExperimentalEthernet today. It was developed by RobertMetcalfe in 1972 (patented in 1978) and was based in part on the wireless ALOHAnetprotocol. The first Ethernet that was generally used outside Xerox was DIX Ethernet, followed by Ethernet II. IEEEdefines a 802.3 standard where the Type field is replaced by Length, and an802.2 LLC header follows with the Type field. However, as DIX Ethernet wasderived from Experimental Ethernet, and as many standards have been developedthat are based on DIX Ethernet, the technical community has accepted the termEthernet for all of them. Therefore, the term Ethernet can be used toname 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 IEEE802.3 standards is often confused for what is used in practice: most networkframes you will find on an Ethernet will be DIX frames, since the Internet protocol suite will use thisformat, with the type field set to the corresponding IETF protocol type. IEEE802.3x-1997 allows the 16-bit field after the MAC addresses to be used as atype field or a length field, so that DIX frames are also valid 802.3 frames in802.3x-1997 and later versions of the IEEE 802.3 Ethernet standard.