NETGEAR FE116 Installation Manual page 12

Fast Ethernet Technology
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Fast Ethernet is conventional Ethernet but faster. Fast Ethernet, or 100BASE-TX, operates at 100
Mbps instead of 10 Mbps. The 100BASE-TX technology uses the same frame format and length
as Ethernet and does not require changes to the upper-layer protocols, applications, or networking
software that run on LAN workstations. If your network is migrating from 10 to 100 Mbps, you
can switch and route data from 10 Mbps to 100 Mbps without protocol translation and its
associated delays. Fast Ethernet is based on the proven CSMA/CD Media Access Control (MAC)
Protocol.
The most popular cabling scheme in an Ethernet network today is star-wired topology, where the
hub is in a central wiring closet and individual cables run out to each tabletop device. This
topology is the same topology used by Fast Ethernet, although the maximum allowable network
diameter is smaller because of the increase in packet speed.
Cable Guidelines for Fast Ethernet
Fast Ethernet uses UTP cable, as specified in the IEEE 802.3u standard for 100BASE-T. The
specification recommends Category 5 UTP cable consisting of either 2-pair or 4-pair twisted
insulated copper conductors bound in a single plastic sheath. Category 5 cable is certified up to
100 MHz bandwidth. 100BASE-TX operation uses one pair of wires for transmission and the
other pair for receiving.
When installing Category 5 UTP cabling, use the following guidelines to ensure that your cables
perform to the following specifications:
• Certification
Make sure that your Category 5 UTP cable has completed the Underwriters Laboratories
(UL) or Electronic Testing Laboratories (ETL) certification process.
• Termination method
To minimize crosstalk noise, maintain the twist ratio of the cable up to the point of
termination; untwist at any RJ-45 connector or patch panel should not exceed 0.5 inch (1.5
cm).
Cable Lengths for Fast Ethernet
Category 5 distributed cable that meets ANSI/EIA/TIA-568-A building wiring standards can be a
maximum of 328 feet (100 m) in length, divided as follows:
• 20 feet (6 m) between the hub and the patch panel (if used)
• 295 feet (90 m) from the wiring closet to the wall outlet
• 10 feet (3 m) from the wall outlet to the desktop device
The patch panel and other connecting hardware must meet the requirements for 100 Mbps
operation (Category 5). Workmanship quality is a must. Only 0.5 inch (1.5 cm) of untwist in the
wire pair is allowed at any termination point.
Model FE116 Fast Ethernet Hub Installation Giude