Tài liệu Fact Sheet - 10GBase-T - Australia Standard CT-1 Committee 2006 docx

10 GBASE-T and the new cabling Classes
Standards Australia CT-1 Committee Fact Sheet

By Peter Meijer March 2006


The Australian Standards telecommunications experts in the CT-1 committee have agreed on a position paper
stating the current facts in relation to 10 Gigabit Ethernet cabling. There were no objections from 22 technical
experts on the content of the document although a few did not respond or participate in the debate. In that
sense, this is an historic achievement and argues well for the introduction of 10GBE cabling systems.

Item Comment Agreed by CT-1 Majority


In the absence of a finalised standard, which draft standard should be referenced?
1
The name given to next generation cabling systems is Class E
A
and Class F
A
.
Note the correct reference to both of these is to use subscript A.
2
Class E
A
standards work is due to be finalised sometime during 2007 due to the fact that work on
specifying components will not be completed during 2006. Channel limits are due to be published
by June 2006. It should be noted that component level specifications are required to achieve
interoperability between products.
3

Augmented Category 6 (can be referred to as Category 6A or AC6) standards are being worked on
by the USA TIA standards committee at the same time as ISO is working on creating a Class E
A

standard.
4
Australian Standards personnel are involved with ISO standards development and the finalised
Australian standard will be based on the ISO standards position, not the TIA standards position.
5
As far as cabling systems go, compliance with the upcoming 10GBASE-T requirements is only part
of the story, compliance with Class E
A
should be the aim of anyone involved in installing a next
generation cabling system.
6
There are differences between the current TIA position and ISO position in regards to the
performance levels of various parameters for Class E
A
and Cat 6A. ISO Class E
A
performance
requirements are higher than TIA Cat 6A performance requirements. New projects in Australia
requiring such performance should only specify compliance with Class E
A
draft standards as
specifying compliance with both draft standards only creates confusion.

The IEEE position (those writing the 10GBASE-T standard)
1
Existing Class E (Cat 6) UTP cabling should support cabling channels of up to 55 m. It should be

noted that this information should not be used for making decisions on newly installed systems and
is only for qualification of legacy cabling systems.
2 Class E (Cat 6) screened cabling will support 10GBASE-T channels up to 100 m.
3 Class F (sometimes referred to as Cat 7) screened will support 10GBASE-T channels up to 100 m.
4 Class E
A
cabling will support 10GBASE-T channels up to 100 m when standards work is completed.
5 10GBASE-T application standard is due to be completed in June 2006 and is still on track.
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10 GBASE-T and the new cabling Classes
Standards Australia CT-1 Committee Fact Sheet

By Peter Meijer March 2006

Item Comment Agreed by CT-1 Majority
Current Class D (Cat 5e) position and future
1 Currently characterised up to 100 MHz and this describes a 4 connector cabling channel.
2 Will support 1000BASE-T channels up to 100 m.
3
No work is being done on qualifying the ability of Class D to support 10GBASE-T but it has been left
for customers to decide whether to try and use an installed base of Class D / Cat 5e to support very
short runs of 10GBASE-T in the future. This is not recognised within standards work.
4 T/O remains as an RJ45.

Current Class E (Cat 6) position and future
1 Currently characterised up to 250 MHz and this describes a 4 connector cabling channel.
2 Will support 1000BASE-T channel up to 100 m.
3
Class E UTP could support 10GBASE-T on cabling channels of up to 55 m. There are still some

unknowns and a number of on site issues that may affect this being correct for all installed sites.
The draft standard TR-24750 lists a number of mitigation procedures that can be used if an installed
system is found not to be able to support the 10GBASE-T application. TR-24750 is intended to be
used to qualify legacy systems and not for the qualification of the design of new systems. The
reason for this is that there are still a number of outstanding issues to do with this discussion and
even 55 m cabling channels (or shorter) using Class E UTP cabling may need changes made to be
able to support the 10GBASE-T application successfully.
4
Class E screened cable will support 10GBASE-T on cabling channels of up to 100 m. It is important
to note that although the existing Class E screened systems will support the 10GBASE-T
application on cabling channels up to 100 m, a Class E screened system will not necessarily comply
with the new Class E
A
requirements, as a Class E
A
channel will require higher performance than the
10GBASE-T application will require.
5
The ISO standards body has decided to leave Class E in place and document Class E
A
as an
additional new system.
6 T/O remains as an RJ45.

Class E
A
position and future
1
Class E
A

standards work is due to be finalised sometime during 2007 due to the fact that work on
specifying components will not be completed during 2006. Channel limits are due to be published in
late 2006. It should be noted that component level specifications are required to achieve
interoperability between products.
2 Class E
A
is being characterised up to 500 MHz and this describes a 4 connector cabling channel.
3 When finalised it will support 10GBASE-T on cabling channels up to 100 m.
4 Individual components, when finalised, will be known as Cat 6
A
components.
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10 GBASE-T and the new cabling Classes
Standards Australia CT-1 Committee Fact Sheet

By Peter Meijer March 2006
5
Class E
A
is a performance requirement and does not limit any channels to being constructed from
using either UTP or screened components as long as the products meet the performance
requirement of all parameters of the finalised standard. Given that the 10GBASE-T application can
be supported by a Class E screened cabling channel up to 100mtrs it is accepted that a Class E
A

screened system will exhibit better ANEXT performance than a Class E
A
UTP system.
Item Comment Agreed by CT-1 Majority

6 The major changes to the channel requirements over and above Class E are as follows:
6a. Insertion loss requirements are derived from current Class F insertion loss requirements.

6b. ANEXT (Exogenous Crosstalk) figures for Class E
A
channels have been defined but the ability
to test and prove compliance in the field is still to be qualified. Laboratory testing is available but
this cannot qualify in-field performance as ANEXT performance can be affected by installation
practices.
7 T/O remains as an RJ45.

Current Class F position and future
1 Currently characterised up to 600 MHz and this describes a 4 connector cabling channel.
2 Class F will support 10GBASE-T on cabling channels up to 100 m.
3
Currently TIA have not ratified and are not doing any work to ratify a Cat 7 system within their
standards.
4 ISO has decided to leave Class F in place and document Class F
A
as an additional new system.
5
Preferred T/O within ISO is RJ45 but alternative option exists if backward compatibility is not
important to the end user and factors such as HEM (Home Entertainment and Multimedia) are
evident.

Class F
A
position and future
1
Class F

A
standards work is due to be finalised sometime during 2007 due to the fact that work on
specifying components will not be completed during 2006. Channel limits are due to be published in
late 2006. It should be noted that component level specifications are required to achieve
interoperability between products.
2 Class F
A
is being characterised up to 1000 MHz and this describes a 4 connector cabling channel.
3 When finalised, it will support 10GBASE-T on cabling channels up to 100 m.
4 Individual components, when finalised, will be known as Cat 7
A
components.
5
A number of countries around the world use TV signals that operate within a frequency level of up to
862 MHz and so the main reason for characterisation to a higher level is to allow support of
broadband (TV cabling) over twisted pair which will mainly affect domestic style cabling
requirements in those countries. This also reflects the fact that this level of performance represents
current state of the art capability for twisted pair cabling.
6 T/O currently undecided
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10 GBASE-T and the new cabling Classes
Standards Australia CT-1 Committee Fact Sheet

By Peter Meijer March 2006

Item Comment Agreed by CT-1 Majority


Testing

1
Field testing for current Class D, Class E and Class F systems remains unchanged for both UTP
and screened systems.
2
Manufacturers of field testers have released in-field testers that are stated to have Level 4
compliance, which is the level required for Class E
A
testing. These are currently available to allow
for testing of most parameters of a Class E
A
channel but the ability to simply and economically test
for ANEXT performance in the field remains undecided.
3
ANEXT (Exogenous Crosstalk) performance cannot be currently tested for and fully qualified in the
field. Laboratory testing is available but this cannot qualify in-field performance as ANEXT
performance can be affected by installation practices.

It must be noted that in the absence of finalised component specifications, interoperability between cabling
systems and products cannot be guaranteed. This in turn means that in-field channel testing, although
available, cannot guarantee to provide exact results. This is simply because in the absence of component
specifications, the tester manufacturers are not able to use a standard's compliant "test head" for testing the
channels. However, it is understood that in the absence of finalised component specifications, channel testing
with a current Level 4 tester is the best option available. When component specifications are finalised it is
envisaged that the availability of standard's compliant "test heads" from the various tester manufacturers will
allow for qualified permanent link and channel testing of installed sites.

Segregation
1
In regards to safety issues and standards, the segregation requirements between communications
and power cabling remains unchanged at present.

2
In regards to performance issues there is still work being done on what segregation is required
between communications and power cabling. Users could consider adopting manufacturer's current
recommendations while considering recommendations from other standards documents. The
implication on pathway costs when considering the issue of segregation due to performance issues
could be significant.


UTP versus screened for 10GBASE-T
1
Both UTP and screened cabling cannot be tested easily and inexpensively for ANEXT performance
in the field today. Both newly developed UTP systems as well as existing and newly developed
screened systems may deliver the required ANEXT performance although neither can be easily
proven to do so in the field. Properly installed screened systems (using either overall screened or
individually screened per pair cable and individually screened connectors that are commonly
earthed) will comply with the ANEXT requirements of the upcoming standards whereas UTP
systems may need other ways to be qualified somehow.
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10 GBASE-T and the new cabling Classes
Standards Australia CT-1 Committee Fact Sheet

By Peter Meijer March 2006
2
In regards to the issue of segregation there is still work being done to qualify the effect on
performance when communications cabling and power cable are run parallel to each other either on
some sort of tray or in duct using dividers. Properly screened systems will require less segregation
than UTP systems when it comes to performance issues. Segregation requirements for safety
issues remain the same for both UTP and screened systems. Please also note that 10GBASE-T
systems may be more sensitive to noise induced from power circuits than existing applications.

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