Media & Cabling Distribution

Question 1

Coaxial Cable

Answer 1

Inner: Insulated conductor or center wire passes data

Outer: Braided metal shield used to help protect the data transmission (EMI resistance)

Question 2

Coaxial Cable Types

Answer 2

RG-6: Used by local cable companies to connect individual homes

RG-59: Used to carry composite video between two nearby devices

Question 3

Coaxial Cable Connectors

Answer 3

BNC (Bayonet Neill-Concelman - British Naval Connector):
Was used for 10BASE2 Ethernet Networks

F-Connector:
Typically used for cable TV & cable modem connections

Question 4

Twisted Pair Cables

Answer 4

Most popular LAN media type
8 individually insulated strands of copper wire
Each pair twisted to reduce EMI
(Tighter twists = less EMI)

UTP & STP

Question 5

UTP

Answer 5

Unshielded Twisted Pair
Media of choice in most LANs
Number of twists determines EMI amount blocked
(CAT6 has more twists per inch than CAT5)

Question 6

STP

Answer 6

Shielded Twisted Pair
Wires are surrounded by a metallic shielding to minimize EMI

Shielding makes STP more costly and less flexible than UTP

Question 7

Twisted Pair Connectors

Answer 7

RJ-45: 8-pin connector in Ethernet networks
Most Ethernet use only 4-pins

RJ-11: 6-pin connector (telephone systems)
Commonly only 2/4 pins are used

DB-9 or DB-25 (9 or 25-pin D-Subminiature)
Used for asynchronous serial communications & connecting to an external modem

Question 8

Twisted Pair Cable Throughput

Answer 8

CAT3: 10Mbps - 100m
CAT5: 100Mbps - 100m
CAT5e: 1Gbps - 100m
CAT6: 1Gbps - 100m
CAT6a: 10Gbps - 100m
CAT7: 10Gbps - 100m

Question 9

Straight-Through Patch Cables

Answer 9

Both ends of the cable have matching pin outs

T-568B is the preferred standard for wiring a building

Question 10

DTE to DCE

Answer 10

Data Terminating Equipment to Data Communications Equipment

Examples: Computer to switch
Router to modem

Question 11

Crossover Cables

Answer 11

Send & receive pins of the cable are swapped in the end pin outs.

Used to connect two workstations
Or a switch to a switch
(Not required if switch supports MDIX)

Question 12

T568B vs. T568A

Answer 12

T568B:
OW, O, GW, B, BW, G, BrW, Br

T568A:
GW, G, OW, B, BW, O, BrW, Br

Question 13

Fiber Optic Cables

Answer 13

Use light from LED or laser to transmit info through glass fiber.
Immune to EMI, uses light instead of electricity

Great range, greater data-carrying capacity (Tbps)

Types: MMF & SMF

Question 14

MMF

Answer 14

Multimode Fiber
Shorter distances than single-mode
Larger core sizes allows for multiple modes of travel for the light signal (62.5 microns)

Uses: Routers to switches
Switches to switches
Servers to switches

Question 15

SMF

Answer 15

Single-Mode Fiber
Longer distances than multimode
Smaller core allows for only a single mode of travel for the light signal (10 microns)

Uses: Routers to switches
Switches to switches

Question 16

Fiber Optic Connectors

Answer 16

SC (Subscriber Connector) - “Stick & Click”
ST (Straight Tip Connector) - “Stick & Twist”
LC (Lucent Connector) - Looks like two SCs
MTRJ (Mechanical Transfer Registered Jack)

Refer to diagrams on Dion study guide

Question 17

Copper vs. Fiber Optic Cables

Answer 17

Fiber Optic: (40Km+, 69Tbps+)
Higher bandwidth
longer distances
Immune to EMI
Better security

Copper: (<100m, 10Gbps)
Less expensive
Easy to install
Inexpensive tools

Question 18

Media Converters

Answer 18

Convert media from one format to another
Layer 1 Device (physical conversion of signal only)

Ethernet to Fiber Optic
Fiber Optic to Ethernet
Coaxial to Fiber
Fiber to Coaxial

Question 19

Cable Distribution System Components

Answer 19

Entrance Facilities
Main Distribution Frame (MDF)
Cross-connect Facilities
Intermediate Distribution Frame (IDF)
Backbone Wiring
Telecommunications Closet
Horizontal Wiring
Patch Panels
Work Area

Question 20

Punch Down Blocks

Answer 20

66 Block:
Used for phones & older LAN wiring
Causes crosstalk due to proximity of cables
Do not use for CAT5 and above

110 Block:
Used for higher-speed network wiring
Required for CAT5 and above

Krone Block:
A proprietary European alternative to a 110 block

BIX Block:
Another proprietary punch down block (various sizes)
Requires a BIX specific punch down tool

Question 21

Patch Panels (Copper)

Answer 21

Device with jacks to connect wiring from the jack to a network switch in a flexible manner

Back has punch downs like a 110 block to connect wiring to wall jacks in building

Front has RJ-45 jacks

Question 22

Patch Panels (Fiber)

Answer 22

Connect fiber jacks throughout building to a single patch panel in network closet

Front uses patch cables to connect to different wall jacks & switch ports

Question 23

Fiber Optic Connector Types

Answer 23

SC (Stick & Click)
ST (Stick & Twist)
LC (Love Connector - Like two SCs attached)
MTRJ (Looks like an RJ-45 kind of; one plastic piece with two connectors)

Question 24

Specialized Fiber Optic Connectors

Answer 24

APC (Always Green) - Usually for SC

UPC (Always Blue) - Usually for MTRJ

Question 25

WDM

Answer 25

Wavelength Division Multiplexing:
Combines multiple signals into one signal & sends over a single fiber optic strand using different wavelengths of the laser light source

Question 26

Coarse WDM (CWDM)

Answer 26

Up to 18 channels

20nm

Up to 10Gpbs (Ethernet)
Up to 16Gbps (Fiber)

Question 27

Dense WDM (DWDM)

Answer 27

Up to 80 channels

0.8nm

Up to 8 Tbps
(100Gbps/channel)

Question 28

GBIC

Answer 28

Standard, hot-pluggable gigabit ethernet transceiver (copper/fiber)

Question 29

SFP

Answer 29

Small Form-Factor Pluggable (Mini GBIC)
Compact, hot-pluggable optical module transceiver
Up to 4.25Gbps

Question 30

SFP+

Answer 30

Enhanced SFP

Up to 16Gbps

Question 31

QSFP

Answer 31

Quad Small Form-Factor Pluggable
Compact, hot-pluggable optical module transceiver
Up to 40Gbps

QSFP+ = 41.2Gbps
QSFP28 = 100Gbps
QSFP56 = 200Gbps