HP 2920 Installation And Getting Started Manual page 94

Cabling and Technology Information
B-2
Note on 1000BASE-T Cable Requirements The Category 5 networking
cables that work for 100BASE-TX connections should also work for
1000BASE-T, as long as all four-pairs are connected. But, for the most robust
connections, you should use cabling that complies with the Category 5e
specifications, as described in Addendum 5 to the TIA-568-A standard (ANSI/
TIA/EIA-568-A-5).
Because of the increased speed provided by 1000BASE-T (Gigabit-T), network
cable quality is more important than for either 10BASE-T or 100BASE-TX.
Cabling plants being used to carry 1000BASE-T networking must comply with
the IEEE 802.3ab standards. In particular, the cabling must pass tests for
Attenuation, Near-End Crosstalk (NEXT), and Far-End Crosstalk (FEXT).
Additionally, unlike the cables for 100BASE-TX, the 1000BASE-T cables must
pass tests for Equal-Level Far-End Crosstalk (ELFEXT) and Return Loss.
When testing your cabling, be sure to include the patch cables that connect
the switch and other end devices to the patch panels on your site. The patch
cables are frequently overlooked when testing cable and they must also
comply with the cabling standards.
Note on 10GBASE-T Cable Requirements The Category 6 networking
cables that work for 1000BASE-T connections may work for 10GBASE-T, as
long as the distance is less than 55m and the cable installation has been tested
for compliance to IEEE requirements. But, for the most robust connections,
you should use cabling that complies with the Category 6A or Category 7
specifications, as described in the TIA-568-C (ANSI/TIA-568-C.2) and ISO/IEC
11801 standards. 10GBASE-T is a sophisticated technology that relies upon
high quality cable installations. It is sensitive to Alien Near End Crosstalk
(ANEXT) which can arrive upon the cable due to cables placed in close
proximity to the data cables. It is recommended that cable dressing be done
carefully and in compliance with recommendations in the TIA TSB-155A.
Like 1000BASE-T, 10GBASE-T requires testing of all the crosstalk and return
loss parameters described above, and also ANEXT.
In addition to ANEXT, 10GBASE-T is more sensitive to external electrical
noise in the environment. It is recommended that radio transmitters and other
sources of high frequency continuous wave radio frequency be kept away from
LAN cables.
When testing your cabling, be sure to include the patch cables that connect
the switch and other end devices to the patch panels on your site. The patch
cables are frequently overlooked when testing cable and they must also
comply with the cabling standards. For 10GBASE-T, Category 6 patch cables
are sensitive to movement once link has been established, and could cause