Today's focus:  Cat-6 may go farther

By Jeff Caruso

Last month I talked about some of the objectives of the IEEE
study group looking into running 10 Gigabit Ethernet over
unshielded twisted pair wiring. It turns out that some members
of the group are looking to push those objectives a bit further.

Specifically, some organizations think they can push the
distance supported by Category-6 cables to 100 meters, instead
of the minimum 55 meters stated in the group's goals.

Krone in November presented the results of tests of Cat-6 cables
that showed they have a capacity of 20G bit/sec. In the
presentation, Krone said that in its tests the company arranged
six cables around one in the middle, and tested the cables both
in a metal conduit and on the floor. The tests showed that
transmitting 10 Gigabit for 100 meters was possible without the
need for mitigating alien crosstalk.

In a separate presentation, Pennsylvania State University also
noted that there is "every indication that 10Gbps transmission
over 100m of CAT-6 is possible" given the allowed bit error rate
being considered for the standard.

However, Category-6 cabling is still a different wiring than is
installed in a lot of places. Many organizations have installed
Category-5E for their Gigabit Ethernet links, a point raised by
Mike Bennett of Lawrence Berkeley National Laboratory in his
November presentation.

He argued for running 10 Gigabit over Cat-5E, even if it were
only 50 meters; that way, a data center wouldn't have to be
re-cabled to upgrade from Gigabit Ethernet. But that is not
currently one of the study group's objectives.


Presentations from the November meeting

Firm looks to plug in power-line networks
Network World, 01/05/04

Catalyst 6500 management tool on the way
Network World, 01/05/04
To contact: Jeff Caruso

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