The Classification of Networks
2-11
Overview of Networking
UTP cabling is differentiated by the quality of the cable. UTP is divided into
Categories, which indicate the relative quality of the materials used and the
processes used to manufacture the cables. The categories used in LANs range
from Category 3 to Category 5, with Category 5 being the highest quality.
Shielded Twisted Pair (STP)
Shielded Twisted Pair cabling (referred to in this document as STP, but also seen
as “IBM-type” cable or “shielded copper”) is a cable type which is constructed in
much the same fashion as UTP cabling (see Figure 2-4) but incorporates more
elaborate shielding methods. These cables are most commonly used in Token
Ring networks.
As with UTP cable, STP cable consists of two or more pairs of wire. Each wire is
shielded with a layer of insulation, twisted together with a related wire, then
bundled with the other pairs and wrapped in a metal foil. The metal foil provides
additional resistance to the effects of external electrical fields produced by
electrical equipment or other cabling.
STP cabling, like UTP cabling, is divided into groups based on fitness for a
particular purpose. Where UTP referred to Categories of cable, STP cabling is
divided into “types.” These types are based on the IBM Cabling System, and are
often labeled “IBM Type 1 STP.” IBM Type 1 cable is usually the highest quality,
incorporating several layers of shielding and made with heavy-gauge wire, while
Types 6 and 9 STP are usually best suited for use as short jumper cables in
low-interference areas.
Fiber Optics
Fiber optic cable is a high performance media constructed of glass or plastic
which uses pulses of light as a transmission method. Because fiber optics do not
use electrical charges to pass data, they are free from the possibility of interference
due to proximity to electrical fields. This, combined with the extremely low rate of
signal degradation and dB loss makes fiber optics able to traverse extremely long
distances. The actual maximums are dependant upon the technology being used,
but distances upwards of 2 kilometers (1.2 miles) are not uncommon.
Summary of Contents for MMAC-5FNB
Page 1: ...Cabletron Systems Networking Guide MMAC FNB Solutions ...
Page 2: ......
Page 4: ...ii ...
Page 10: ...viii ...
Page 188: ...Expansion Ethernet 8 12 Port Assignment and Virtual LANs ...
Page 194: ...Expansion Token Ring 9 6 Port Assignment ...