Information Technology Reference
In-Depth Information
10 Gigabit Standards and Cabling for Copper
At the onset of 10 Gb LAN technology, users and installers of structured wiring
faced the usual two-pronged dilemma. How does one utilize existing cable and what
cable should be installed in new build-outs? As with its approach to gigabit cabling,
the TIA has very good answers for both of these 10 Gb questions. The answers are:
1) test installed cable to determine the performance parameters that will support 10
GigE operation (is it possible with your cable, and to what extent?), and 2) specify
new performance categories for new cabling installations that will work for 10 GigE
and everything else.
Existing Category 6 Cabling.
Existing Category 6 cable plants constitute a signif-
icant problem. TSB-155, from the TIA, handles this problem by specifying extended
performance measurements that are needed for a 55 m range
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over existing
Category 6 facilities. One of the critical parameters that have been identified for 10
Gbps is called alien crosstalk (ANEXT and AFEXT, as well as the power-sum com-
ponents). Alien crosstalk is basically interference that comes from a source outside
the cable jacket. This was not a test parameter in the original Category 6 standard,
but greatly affects 10 Gb performance. Another very important new test parameter
is the test frequency range of Cat 6. Originally, Cat 6 was tested only to 250 MHz,
but testing to 500 MHz is needed for 10 Gb operation.
TSB-155 and IEEE 802.3an provide for this 55 m option over existing
Category 6 cabled runs. Realistically, a large number of runs are within 55 m (~165
ft) and can support 10 GigE, as-is. You are in good shape if you bought (and prop-
erly installed) cabling and components that meet enhanced performance levels
above the Cat 6 minimums. You can certainly expect to be able to run 10 GigE to
55 m and you might well approach 100 m.
Augmented Category 6 (AC6), Augmented Class E Cabling.
Cable and connector
manufacturers have found ways to construct Cat 6 components with enhanced per-
formance. This performance category is called Augmented Category 6 by the TIA or
AC6, for short. The corresponding IEC standard is Augmented Class E. AC6 is
tested for both 250 and 500 MHz performance in a number of parameters, includ-
ing alien crosstalk. Amendment 10 of TIA-568-B2 is the first to describe these
parameters. The objective is to support 10 GigE to at least 55 to 100 m with Cat 6,
and the full 100 m on AC6 (Augmented Class E) cable. Now, doesn't that give you
hope for the future of copper cabling?
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Although 100 m is the normal length of the shortest channels in TIA-568's structured wiring, a 55
m range is the best that can be expected for Category 6 channels that only meet the minimum specs.
