IEEE 802.3, Ethernet
Description Glossary RFCs Publications Obsolete RFCs

Description:

Protocol suite: TCP/IP.
Protocol type:Data link and physical layer protocol.
Ethertype:
Multicast addresses:
URI:
MIME subtype:
SNMP MIBs: iso.org.dod.internet.mgmt.mib-2.snmpDot3RptrMgt (1.3.6.1.2.1.22).
iso.org.dod.internet.mgmt.mib-2.snmpDot3MauMgt (1.3.6.1.2.1.26).
iso.org.dod.internet.mgmt.mib-2.powerEthernetMIB (1.3.6.1.2.1.105).
Working groups:
Links: IANA: Ethernet assigned numbers.
Preamble SFD IEEE 802.3 header Data ::: FCS

Preamble. 7 bytes.
Indicates that the frame is about to begin.

SFD, Start Frame Delimiter. 8 bits. Always set to 0xAB.
Indicates that the frame delimiter is about to begin.

IEEE 802.3 header

0001020304050607 0809101112131415 1617181920212223 2425262728293031 3233343536373839 4041424344454647
Destination address
Source address
Ethertype Data :::

Destination Address. 6 bytes (48 bits).
MAC address of the destination node. This may be a unicast, multicast or broadcast address.

Source Address. 6 bytes (48 bits).
The unicast MAC address of the source node.

Ethertype. 16 bits.
The number of bytes encapsulated or the protocol type of the next higher protocol.

Data. Variable length, 46 to 1500 bytes.

FCS, Frame Check Sequence. 4 bytes.
A CRC used to verify the integrity of the frame.

Glossary:

CSMA/CD, Carrier Sense Multiple Access with Collision Detection.
Algorithm. Used when transmitting frames. The network is checked for other transmissions. When the way is clear, the frame transmissions can begin. If a collision is detected, a jam frame is generated. A random backoff period is calculated and the frame is scheduled to be retransmitted later.

IEEE 802.3ab, 1000BASE-T.

IEEE 802.3ac, VLAN tagging.
This extension adds the capability to use VLAN tags within the frame. The maximum frame size is increased to 1522 bytes.

IEEE 802.3ad, Link Aggregation.

IEEE 802.3ae, 10Gb/s Ethernet.

IEEE 802.3af, DTE power via MDI.

IEEE 802.3ak, 10GBASE-CX4.

IEEE 802.3z, Gigabit Ethernet.

MAU, Media Access Unit.
A type of hub by which computers share a connection point in a network. Hubs connect different segments of a LAN together.

Repeater.
(RFC 2108) A bitwise store-and-forward device. It recognizes activity and bits, but does not process incoming data based on any packet-related information (such as checksum or addresses). A repeater has no MAC address, no MAC implementation, and does not pass packets up to higher-level protocol entities for processing.

Repeater-unit.
(RFC 2108) The portion of the repeater set that is inboard of the physical media interfaces. The physical media interfaces (MAUs, AUIs) may be physically separated from the repeater-unit, or they may be integrated into the same physical package.

RFCs:

[RFC 1042] A Standard for the Transmission of IP Datagrams over IEEE 802 Networks.

[RFC 2108] Definitions of Managed Objects for IEEE 802.3 Repeater Devices using SMIv2.

[RFC 2239] Definitions of Managed Objects for IEEE 802.3 Medium Attachment Units (MAUs) using SMIv2.

[RFC 2464] Transmission of IPv6 Packets over Ethernet Networks.

[RFC 3621] Power Ethernet MIB.

[RFC 3636] Definitions of Managed Objects for IEEE 802.3 Medium Attachment Units (MAUs).

[RFC 4448] Encapsulation Methods for Transport of Ethernet over MPLS Networks.

Publications:

Obsolete RFCs:

[RFC 948] TWO METHODS FOR THE TRANSMISSION OF IP DATAGRAMS OVER IEEE 802.3 NETWORKS.

[RFC 1368] Definitions of Managed Objects for IEEE 802.3 Repeater Devices.

[RFC 1515] Definitions of Managed Objects for IEEE 802.3 Medium Attachment Units (MAUs).

[RFC 1516] Definitions of Managed Objects for IEEE 802.3 Repeater Devices.

[RFC 1972] A Method for the Transmission of IPv6 Packets over Ethernet Networks.

[RFC 2668] Definitions of Managed Objects for IEEE 802.3 Medium Attachment Units (MAUs).

Description Glossary RFCs Publications Obsolete RFCs