Thinnet (10Base2)
Characteristics
(cont.):

Size and scalability
Allows a maximum
of 185 m per
network segment
(see Figure 4-20)

Noise immunity
More resistant than
twisted-pair wiring
Less resistant
Thicknet
Figure 4-19: Thinnet BNC connectors
Thinnet (10Base2)
Signal bounce



Caused by
improper
termination on
a bus network
Travels
endlessly
between two
ends of
network
Prevents new
signals from
getting through
Figure 4-20: A 10Base2 Ethernet network
Twisted-Pair (TP) Cable
Color-coded pairs of
insulated copper wires
twisted around each
other and encased in
plastic coating
Twists in wire help
reduce effects of
crosstalk

Number of twists per
meter or foot known as
twist ratio
Alien Crosstalk

When signals from
adjacent cables interfere
with another cable’s
transmission
Figure 21: Twisted-pair cable
Shielded Twisted-Pair (STP)
STP cable consists of twisted wire pairs that are
individually insulated and surrounded by shielding
made of metallic substance
Figure 4-22: STP cable
Unshielded Twisted-Pair
Consists of one or more insulated wire pairs
encased in a plastic sheath
Does not contain additional shielding
Figure 4-23: UTP cable
Unshielded Twisted-Pair
To manage
network cabling, it
is necessary to be
familiar with
standards used on
modern networks,
particularly
Category 3 (CAT3)
and Category 5
(CAT5)
Figure 4-24: A CAT5 UTP cable
Unshielded Twisted-Pair
CAT1 – 2 wire pairs; suitable for voice only
CAT2 – 4 wire pairs; up to 4 Mbps throughput
CAT3 – 4 wire pairs; up to 10 Mbps and 16 Mhz
signal
CAT4 – 4 wire pairs; up to 10 Mbps
CAT5 – 4 wire pairs; up to 100 Mbps and 100
Mhz signal
CAT5e – up to 200 Mhz signal
CAT6 – additional foil insulation; 6x throughput
than CAT5
CAT7 – unfinished standard – up to 1Ghz
10BaseT
Popular Ethernet networking standard that replaced
10Base2 and 10Base5 technologies
“T” for twisted pair
Figure 4-25: A 10BaseT Ethernet network
10BaseT
Enterprise-wide
network


Spans entire
organization
Often services
needs of many
diverse users
Figure 4-26: Interconnected 10BaseT segments
100BaseT
Enables LANs to run at 100-Mbps data
transfer rate
Also known as Fast Ethernet
Two 100BaseT specifications have competed
for popularity as organizations move to 100Mbps technology:


100BaseTX
100BaseT4 (can use CAT3 cabling)
100BaseVG
Cousin of Ethernet 100 Mbps technologies
VG stands for voice grade
Also called 100VG-AnyLAN
Originally developed by Hewlett-Packard
and AT&T
Now governed by IEEE standard 802.12
Requires more sophisticated NICs and
can reduce network performance
Comparing STP and UTP
Throughput

Both can transmit up to 100 Mbps
Cost

Typically, STP is more expensive
Connector

Both use RJ-45 connectors and data jacks
Noise immunity

STP is more noise-resistant
Size and scalability

Maximum segment length for both is 100 meters
Fiber-Optic Cable
Contains one or
several glass
fibers at its
core

Surrounding
the fibers is a
layer of glass
called
cladding
Figure 4-28: A fiber-optic cable
Fiber-Optic Cable
Single-mode
fiber

Carries light
pulses along
single path
Multimode fiber

Many pulses of
light generated
by LED travel at
different angles
Figure 4-29: Single-mode and
multimode fiber-optic cables
Fiber-Optic Cable
Throughput

Reliable in transmitting up to 1 gigabit per
second
Cost

Most expensive type of cable
Connector

You can use any of 10 different types of
connectors
Fiber-Optic Cable
Two popular connectors used with fiber-optic
cable:


ST connectors
SC connectors
Figure 4-30: ST and SC fiber connectors
Fiber-Optic Cable
Noise immunity

Unaffected by either EMI or RFI
Size and scalability


Network segments made from fiber can span
100 meters
Signals transmitted over fiber can experience
optical loss
10BaseF and 100BaseFX
10BaseF

Physical layer standard for networks
specifying baseband transmission, multimode
fiber cabling, and 10-Mbps throughput
100BaseFX

Physical layer standard for networks
specifying baseband transmission, multimode
fiber cabling, and 100-Mbps throughput
Physical Layer Networking
Standards
Table 4-3: Physical layer networking standards
Cable Design and Management
1991 – TIA/EIA released its joint 568
Commercial Building Wiring Standard




TIA – Telecommunication Industry Assoc.
www.tiaonline.org
EIA – Electronic Industries Assoc.
www.eia.org
T568A
T568B
Cable Design and Management
Cable plant

Hardware
comprising
enterprise-wide
cabling system
Structured cabling

Method for
uniform,
enterprise-wide,
multivendor
cabling systems
Figure 4-31: TIA/EIA structured cabling subsystems
Cable Design and Management
Entrance facilities
Backbone wiring

Backbone cabling that provides vertical
connections between floors of a building are
called risers
Table 4-4: TIA/EIA specifications for backbone cabling
Cable Design and Management
Equipment room
Telecommunication
closet

Punch-down
block is a panel of
data receptors

Patch panel is a
wall-mounted panel
of data receptors
Figure 4-32: Patch panel (left) and
punch-down block (right)
Cable Design and Management
Horizontal wiring
Max distance is 100m
Figure 4-33:
Horizontal
wiring
Cable Design and Management
Work area

Patch cable is a
relatively short
section of twistedpair cabling with
connectors on both
ends that connect
network devices to
data outlets
Figure 4-34: Standard TIA/EIA wall jack
Cable Design and Management
Figure 4-35: A structured cabling hierarchy
Installing Cable
Figure 4-36: A
typical UTP
cabling
installation
Installing Cable
* T568A Standard
Table 4-5: Pin numbers and color codes for an RJ-45 connector
Installing Cable
Straight-through cable

Terminations at both ends are identical
Crossover cable

Terminations locations of transmit and receiver wires on one end
of cable are reversed
Figure 4-37:
RJ-45
terminations
on a
crossover
Installing Cable
Do not untwist twisted-pair cables more than
one-half inch before inserting them
Do not strip off more than one inch of
insulation from copper wire in twisted-pair
cables
Watch bend radius limitations for cable
being installed
Test each segment of cabling with cable tester
Use only cable ties to cinch groups of cable
together
Installing Cable
Avoid laying cable across floor where it
may sustain damage
Install cable at least three feet away from
fluorescent lights or other sources of EMI
Always leave slack in cable runs
If running cable in plenum, area above
ceiling tile or below subflooring, make sure
cable sheath is plenum-rated
Pay attention to grounding requirements
Atmospheric Transmission Media
Infrared transmission



Infrared networks use infrared light
signals to transmit data through space
Direct infrared transmission depends
on transmitter and receiver remaining
within line of sight
In indirect infrared transmission,
signals can bounce off of walls, ceilings,
and any other objects in their path
Atmospheric Transmission Media
RF transmission

Radio frequency (RF) transmission relies

on signals broadcast over specific frequencies
Very susceptible to interference
Two most common RF technologies:

Narrowband

Concentrates RF energy at a single frequency
Spread spectrum

Distributed over several frequencies simultaneously
Choosing the Right Transmission
Media
Areas of high EMI or RFI
Corners and small spaces
Distance
Security
Existing infrastructure
Growth