Re: Home ethernet

In the past I have found Black Box a good source of technical info.  From:
http://www.blackbox.com/Store/Results.aspx/Cables/CAT6a/n-4294955977


Black Box Explains...Category 5, 5e, and 6 copper wiring standards.
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The ABCs of standards
There are two primary organizations dedicated to developing and
setting structured cabling standards. In North America, standards are
issued by the Telecommunications Industry Association (TIA), which is
accredited by the American National Standards Institute (ANSI). The
TIA was formed in April 1988 after a merger with the Electronics
Industry Association (EIA). That’s why its standards are commonly
known as ANSI/TIA/EIA, TIA/EIA, or TIA.

Globally, the organizations that issue standards are the International
Electrotechnical Commission (IEC) and the International Organization
for Standardization (ISO). Standards are often listed as ISO/IEC.
Other organizations include the Canadian Standards Association (CSA),
CENELEC (European Committee for Electrotechnical Standardizations),
and the Japanese Standards Association (JSA/JSI).

The committees of all these organizations work together and the
performance requirements of the standards are very similar. But there
is some confusion in terminology.

The TIA cabling components (cables, connecting hardware, and patch
cords) are labeled with a ”category.” These components together form a
permanent link or channel that is also called a ”category.” The
ISO/IEC defines the link and channel requirements with a ”class”
designation. But the components are called a ”category.”

The Standards
Category 5 (CAT5), ratified in 1991, was the de facto standard for
100-Mbps networks during the 1990s. It is no longer recognized by the
TIA/EIA for use in data networking.

Category 5e (CAT5e)–ISO/IEC 11801 Class D, ratified in 1999, is
designed to enable twisted-pair cabling to support full-duplex, 4-pair
transmission in 100-MHz applications. The CAT5e standard added more
headroom and established new requirements to support Gigabit Ethernet
over a worst case four-connector channel. These include stricter specs
for Near-End Crosstalk (NEXT) and Return Loss (RL). The standard also
introduced the required measurements for Power Sum Near-End Crosstalk
(PS-NEXT), Equal-Level Far-End Crosstalk (EL-FEXT), and Power Sum
Equal-Level Far-End Crosstalk (PS-ELFEXT). CAT5e is still used in many
organizations, although it is no longer recognized for new
installations.

Category 6 (CAT6)–Class E has a specified frequency of 250 MHz,
significantly improved bandwidth capacity over CAT5e, and easily
handles Gigabit Ethernet transmissions. In recent years, it has been
the cable of choice for new structured cabling systems. CAT6 supports
1000BASE-T and, depending on the installation, 10GBASE-T (10-GbE).

10-GbE over CAT6 introduces the problem of Alien Crosstalk (ANEXT),
the unwanted coupling of signals between adjacent pairs and cables.
Because ANEXT in CAT6 10-GbE networks is so dependent on installation
practices, TSB-155 qualifies 10-GbE over CAT6 up to 55 meters and
requires it to be 100% tested. To mitigate ANEXT in CAT6, it is
recommended that you unbundle the cables and increase the separation
between the cables.

Augmented Category 6 (CAT6a)–Class Ea was ratified in February 2008.
This standard calls for 10-Gigabit Ethernet data transmission over a
4-pair copper cabling system up to 100 meters. CAT6a extends CAT6
electrical specifications from 250 MHz to 500 MHz. It introduces the
ANEXT requirement. It also replaces the term Equal Level Far-End
Crosstalk (ELFEXT) with Attenuation to Crosstalk Ratio, Far-End (ACRF)
to mesh with ISO terminology. CAT6a provides improved insertion loss
over CAT6. It is a good choice for noisy environments with lots of
EMI. CAT6a is also well-suited for use with PoE+.

CAT6a UTP cable is significantly larger than CAT6 cable. It features
larger conductors, usually 22 AWG, and is designed with more space
between the pairs to minimize ANEXT. The outside diameter of CAT6a
cable averages 0.29–0.35" compared to 0.21–0.24" for CAT6 cable. This
reduces number of cables you can fit in a conduit. At a 40% fill
ratio, you can run three CAT6a cables in a 3/4" conduit vs. five CAT6
cables.

There are two types of CAT6a cable, UTP and F/UTP. For a discussion of
the differences, see the white paper in our Resources section.

Category 7 (CAT7)–Class F was published in 2002 by the ISO/IEC. It is
not a TIA recognized standard. Class 7 specifies minimum performance
standards for fully shielded cable (individually shielded pairs
surrounded by an overall shield) transmitting data at rates up to 600
MHz. It offers greater capacity for demanding applications such as
broadband video. It’s also well suited for applications where fiber
optic cable would typically be used—but it costs less. Because each
CAT7 pair is fully shielded, it's ideal for areas prone to EMI/RFI.
Class 7 cable offers two connector styles: the standard RJ plug and a
non-RJ-style plug and socket interface specified in IEC 61076-2-104:2.

Category 7a (CAT7a)–Class Fa is currently in ISO standards for channel
performance in Amendment 1, recently component performance has been
ratified in Amendment 2. The formal names are ISO 11801 Amendment 1
(2008) and ISO 11801 Amendment 2 (2010). Class Fa cable is a fully
shielded cable that extends frequency from 600 MHz to 1000 MHz. It can
easily handle 10-GbE and offers users a lifespan of 15 years or more.
It has even been discussed that Class Fa cable is the future for
40GBASE-T or more.


For a comparison chart of category performance standards, see the
Buyer's Guide in the Resources section.

______________________________________________

John Bundy

On Sun, Mar 6, 2011 at 8:15 PM, Carl Karsten <[email protected]> wrote:
> I would say it is a gamble that prolly wont pay off.
>
> The electrician can't run the cat5  in/out the same boxes as the 110v.
>  Code doesn't let networking guys stick screwdrivers in the 110 boxes.
>  So he will have to do 'something else' and whatever that is will cost
> money.  My guess is each termination will be at least $10 labor and $5
> hardware (box, face plate, rj45).  So if you run something from a room
> that might have a server to a room that might have a media box, $30.
> to make sure you get it right, 5 rooms, so $300.  plus $80 cable.
>
> So $100's for something that you aren't sure what you will use it for.
>
> I would just use wifi.
>
> If you do go with cable, there is good and bad cable.  I hear the home
> depo $80/1000' is crap.
>
> I don't know about this product, but I love monoprice:
> http://www.monoprice.com/products/subdepartment.asp?c_id=102&cp_id=10233
>
> On Sun, Mar 6, 2011 at 7:45 PM, Larry Garfield <[email protected]> wrote:
>> Greetings, geeks.
>>
>> I have recently purchased a house (I'm still in shock), and having some
>> renovations done before I move in.  One I am strongly considering is adding
>> ethernet wiring in key locations, on the grounds that the electrician is
>> already there messing around inside the walls so I may as well.
>>
>> Has anyone else done this before?  Any major warnings about what not to do?
>>
>> I'm also debating the cable grade to use.  On the one hand, I figure I should
>> go for the highest grade available so that I don't have to do this again,
>> which would be Cat 7.  However, as I understand it Cat 7 is still quite
>> expensive for the wire itself, and according to Wikipedia at least is not as
>> big a leap over Cat 5 or Cat 6 as it's marketed as:
>>
>> http://en.wikipedia.org/wiki/Category_7_cable
>>
>> My understanding had been that Cat 6 wasn't truly standardized, just a
>> marketing term, but Wikipedia again disagrees there:
>>
>> http://en.wikipedia.org/wiki/Cat_6
>>
>> I've long since given up being a networking geek and moved on to being a web
>> programming geek, so I'm a bit out of my element here.  Any advise or
>> experience anyone has to share would be most appreciated.
>>
>> --Larry Garfield
>> --
>> Linux Users Of Northern Illinois (Chicago) - Technical Discussion
>> http://luni.org/mailman/listinfo/luni
>>
>
>
>
> --
> Carl K
> --
> Linux Users Of Northern Illinois (Chicago) - Technical Discussion
> http://luni.org/mailman/listinfo/luni
>
-- 
Linux Users Of Northern Illinois (Chicago) - Technical Discussion 
http://luni.org/mailman/listinfo/luni