Up to Speed
The key to broad use of 10GigE
Traditional RJ-45 Ethernet at
10-gigabit speed will mainstream copper
connectivity.
by Kamal Dalmia
BASE-T, or twisted-pair copper cable with
RJ-45 connectors, is the most cost-effective
and easiest way to create Ethernet local
area networks. It is the connectivity of
choice for more than 90 percent of the links
in data centers, and the nearly exclusive
connection to the corporate desktop and
notebook computers. It provides a simple
plug-and-play paradigm that allows IT
managers to connect any RJ-45 to any other,
with the technology providing automatic
connection and rate sensing that promises
interoperability with the vast variety of
equipment present in every IT installation.
10GBASE-T brings this time-tested use
model to the 10-Gbps rate of Ethernet. The
IEEE standard for 10GBASE-T prescribes
full-duplex operation over the four wire
pairs present in every RJ-45 jack. In
addition, the standard incorporates
enhancements to the traditional
auto-negotiation protocol, enabling backward
compatibility to the billions of RJ-45 ports
already deployed in IT installations
worldwide.
Continuing the ease of deployment theme,
10GBASE-T is specified to work over existing
CAT 6 cable, as well as a number of other
cable types. The standard requires a channel
with 500 MHz of bandwidth on the cable. CAT
6 cable complying with the IEEE standard is
guaranteed to support transmissions up to 55
meters.
The cable industry is providing further
support for the standard and has created an
augmented CAT 6 (CAT 6a) cable that has been
designed to reduce cable-to-cable crosstalk
(i.e., alien crosstalk) and enables links of
up to 100 meters. Additionally shielded
cable, or CAT 7, is called out in the
standard to also extend up to 100 meters.
Several vendors are in production with
silicon products that implement 10GBASE-T
and have demonstrated interoperability
between their implementations. This is a
clear signal of the maturity of the standard
and the ability to carry the written
document to a practical implementation. A
number of equipment vendors of switches,
network interface cards and servers have
recently announced they are now sampling
10GBASE-T products, and full networks were
demonstrated at November's SC-07 show in
Reno, Nev., using products from a number of
companies.
This year, 10GBASE-T is expected to hit
the data center floor. Several switch and
server vendors performed field trials of
their products in late 2007, with others
scheduled for early 2008, gearing up for
general availability of the products in
coming months. Switches priced near or below
$500 per port are promised, and, at these
port prices, 10GBASE-T will be cheaper per
gigabit than 1-GigE connections.
Early applications are likely to include
high-performance computing clusters, as the
increased rate of communication from 1
gigabit to 10 gigabit reduces the transport
latency of the link to well under that of 1
GigE. In more mainstream data centers,
10GBASE-T will be used in applications where
previously multiple 1-gigabit links needed
to be deployed with "link aggregation" and
can now be replaced by a single cable,
providing both cost and ease-of-management
benefits.
As 10GBASE-T-enabled servers come online
both in rackmount and blade configurations,
they will be deployed with server
virtualization technology, providing a
multiplier on the effectiveness of each
server dollar invested. In the long run, as
technologies such as Fiber Channel over
Ethernet and iSCSI mature,
10GBASE-T
promises to be a candidate for unifying the
whole fabric of the data center on the
simple Ethernet BASE-T model.
Prior to joining Teranetics, Kamal
Dalmia was director of product marketing at
Marvell, where he was instrumental in the
success of several gigabit, 10-gigabit and
Fast Ethernet physical layer products. He
holds several U.S. patents and a master's
degree in electrical engineering from the
University of British Columbia.
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