| 10 Gigabit Ethernet (10 GE or 10 GbE) |
10 Gigabit Ethernet (10GE) Tutorial
- an overview or tutorial about the 10 Gigabit Ethernet (10GE) standard,
IEEE802.3 used for local area network, LAN applications.
10 Gigabit Ethernet, 10GbE or just 10GE is the fastest of the
current Ethernet standards. The 10 Gigabit version of Ethernet has a nominal
data rate of 10 Gbit/s, and the standard supports a number of variants for
operating over different media including optical fibre and twisted pair copper
cable. The version of 10GE for operation over a twisted pair cable has been
released under the IEEE 802.3an amendment.
The development if 10G Ethernet was aimed at providing ever
higher data speeds to meet, or even stay ahead of the requirements being sought.
In this way 10G Ethernet provides an evolution path to enable the overall
standard to remain current and a technology that will be used well into the
future.
One of the basic requirements placed on the development, was
that 10GE should retain backward compatibility and full interoperability with
the previous 10, 100 and 1000 Mbps versions of Ethernet. In doing this 10 G
Ethernet still had to provide a tenfold improvement in performance over its
predecessor 1 Gigabit Ethernet.
Key to 10GE operation
For the previous versions of Ethernet, the MAC layer operates
in a linear fashion with date being moved fundamentally in a serial fashion.
However 10 Gigabit Ethernet operates more in a parallel fashion. The transmit
and receive paths each comprise four data lanes, and the data stream broken down
into bytes is handled in "circular" fashion across the four lanes (0 to 3).
Taking the case of the transmit path, the first byte is assigned to Lane 0; the
second byte to Lane 1, the third to Lane 2, the fourth to Lane 3, the fifth back
to Lane 0, etc.. In this way it is possible to gain a considerable increase in
speed without having such high data rates on each line. Keeping the actual
serial data rates down reduces the transmission difficulties.
Summary
Although 10 Gigabit Ethernet is not as widely used as other
forms of Ethernet, it provides a significant increase in speed over the previous
technologies. The first uses are for backbone installations, but as its use
becomes more widespread, 10GE will be used in more commonplace applications as
well.
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