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The evolution of Ethernet did not stop. In 1998, the IEEE published a first standard to provide Gigabit Ethernet over optical fibers. Several other types of physical layers were added afterwards. The `10 Gigabit Ethernet <http://en.wikipedia.org/wiki/10_gigabit_Ethernet>`_ standard appeared in 2002. Work is ongoing to develop `standards <http://www.ieee802.org/3/ba/public/index.html>`_ for 40 Gigabit and 100 Gigabit Ethernet and some are thinking about `Terabit Ethernet <http://www.networkworld.com/news/2009/042009-terabit-ethernet.html>`_. The table below lists the main Ethernet standards. A more detailed list may be found at http://en.wikipedia.org/wiki/Ethernet_physical_layer.
Standard
Comments
10Base5
Thick coaxial cable, 500m
10Base2
Thin coaxial cable, 185m
10BaseT
Two pairs of category 3+ UTP
10Base-F
10 Mb/s over optical fiber
100Base-Tx
Category 5 UTP or STP, 100 m maximum
100Base-FX
Two multi-mode optical fiber, 2 km maximum
1000Base-CX
Two pairs shielded twisted pair, 25m maximum
1000Base-SX
Two multi-mode or single mode optical fibers with lasers
10 Gbps
Optical fiber but also Category 6 UTP
40-100 Gbps
Optical fiber (experiences are performed with copper)
Footnotes
Additional information about the history of the Ethernet technology may be found at http://ethernethistory.typepad.com/
Initially, the OUIs were allocated by Xerox [DP1981]_. However, once Ethernet became an IEEE and later an ISO standard, the allocation of the OUIs moved to IEEE. The list of all OUI allocations may be found at http://standards.ieee.org/regauth/oui/index.shtml
The official list of all assigned Ethernet type values is available from http://standards.ieee.org/regauth/ethertype/eth.txt
The attentive reader may question the need for different `EtherTypes` for IPv4 and IPv6 while the IP header already contains a version field that can be used to distinguish between IPv4 and IPv6 packets. Theoretically, IPv4 and IPv6 could have used the same `EtherType`. Unfortunately, developers of the early IPv6 implementations found that some devices did not check the version field of the IPv4 packets that they received and parsed frames whose `EtherType` was set to `0x0800` as IPv4 packets. Sending IPv6 packets to such devices would have caused disruptions. To avoid this problem, the IETF decided to apply for a distinct `EtherType` value for IPv6. Such a choice is now mandated by :rfc:`6274` (section 3.1), although we can find a funny counter-example in :rfc:`6214`.
These network interfaces compute the TCP checksum while a segment is transferred from the host memory to the network interface [SH2004]_.
Fortunately, IEEE was able to define the [IEEE802.3]_ frame format while maintaining backward compatibility with the Ethernet [DIX]_ frame format. The trick was to only assign values above 1500 as `EtherType` values. When a host receives a frame, it can determine whether the frame's format by checking its `EtherType/Length` field. A value lower smaller than `1501` is clearly a length indicator and thus an [IEEE802.3]_ frame. A value larger than `1501` can only be type and thus a [DIX]_ frame.
Ethernet Switches
Component Translation Difference to current string
This translation Propagated Read only cnp3-ebook/protocols/ethernet
The following string has the same context and source.
Propagated Read only cnp3-ebook/protocols/lan

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read-only
Source string location
../../protocols/ethernet.rst:177
String age
3 years ago
Source string age
3 years ago
Translation file
locale/pot/protocols/ethernet.pot, string 40