Foundry Networks EdgeIron 2402CF, Руководство по установке

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C
ABLES
B-6 © 2003 Foundry Networks, Inc. February 2003
1000BASE-T Cable Requirements
All Category 5 UTP cables that are used for 100BASE-TX
connections should also work for 1000BASE-T, providing that all
four wire pairs are connected. However, it is recommended that
for all critical connections, or any new cable installations,
Category 5e (enhanced Category 5) or 6 cable should be used.
The Category 5e and 6 specifications include test parameters that
are only recommendations for Category 5. Therefore, the first
step in preparing existing Category 5 cabling for running
1000BASE-T is a simple test of the cable installation to be sure
that it complies with the IEEE 802.3ab standards.
Cable Testing for Existing Category 5 Cable
Installed Category 5 cabling must pass tests for Attenuation,
Near-End Crosstalk (NEXT), and Far-End Crosstalk (FEXT). This
cable testing information is specified in the ANSI/TIA/
EIA-TSB-67 standard. Additionally, cables must also pass test
parameters for Return Loss and Equal-Level Far-End Crosstalk
(ELFEXT). These tests are specified in the ANSI/TIA/
EIA-TSB-95 Bulletin, “The Additional Transmission Performance
Guidelines for 100 Ohm 4-Pair Category 5 Cabling.”
Note that when testing your cable installation, be sure to include
all patch cables between switches and end devices.
Adjusting Existing Category 5 Cabling
If your existing Category 5 installation does not meet one of the
test parameters for 1000BASE-T, there are basically three
measures that can be applied to try to correct the problem:
1. Replace any Category 5 patch cables with high-performance
Category 5e or 6 cables.
2. Reduce the number of connectors used in the link.