Media and Cable Distribution

Question 1

Media

Answer 1

Material used to transmit data over the network

Question 2

Copper Media Types

Answer 2

▪ Three categories:
● Copper
● Fiber optic
● Wireless

Question 3

Coaxial Cable (COAX)

Answer 3

Inner
● Insulated conductor or center wire passes data
▪ Outer
● Braided metal shield used to help shield and protect the data
transmission
● Provides EMI resistance due to shielding

Question 4

Coaxial Cables

Answer 4

RG-6
● Commonly used by local cable companies to connect individual
homes
▪ RG-59
● Typically used to carry composite video between two nearby
devices, such as from a cable box to the television

Question 5

Coaxial connectors

Answer 5

▪ F-connector
● Typically used for cable TV and cable modem connections
▪ BNC
● Termed Bayonet Neill-Concelman or British Naval Connector
● Was used for 10BASE2 Ethernet networks

Question 6

Twinaxial cable

Answer 6

Similar to coaxial cable but uses two inner conductors to carry the data
instead of just one

Question 7

Serial cable

Answer 7

Usually have a series of straight copper wires inside a single cable or
plastic jacket
▪ DB-9 or DB-25 (RS-232)
● 9-pin or 25-pin D-subminiature
● Used for asynchronous serial communications and connecting to
an external modem

Question 8

Twisted pair cables

Answer 8

▪ Most popular physical LAN media type
▪ Eight individually insulated strands of copper wire inside each cable
▪ Each pair twisted together to reduce EMI
● Tighter twists = less EMI
▪ Types:
● Unshielded Twisted Pair (UTP)
● Shielded Twisted Pair (STP)

Question 9

Unshielded twisted pair (UTP)

Answer 9

▪ Number of twists determines how much EMI can be blocked
● CAT 6 has more twists per inch than CAT 5
▪ UTP is cheaper than STP
▪ Media of choice in most LANs

Question 10

Shielded twisted pair (STP)

Answer 10

▪ Wires are twisted in pairs and surrounded in a metallic shielding to
minimize EMI
▪ Outer shielding minimizes EMI, but makes STP cost more than UTP

Question 11

Twisted pair connectors

Answer 11

RJ-45
● 8-pin connector in Ethernet networks
● Most Ethernet use only 4-pins
▪ RJ-11
● 6-pin connector
● Commonly only 2 or 4 pins are used
● Commonly found in telephone systems

Question 12

Registered Jack (RJ)

Answer 12

▪ Used to carry voice or data which specifies the standards a device needs
to meet to connect to the phone or data network

Question 13

Bandwidth

Answer 13

▪ Theoretical measure of how much data could be transferred from a
source to its destination

Question 14

Throughput

Answer 14

▪ Actual measure of how much data transferred from a source to its
destination

Question 15

Cable Legths

Answer 15

▪ Keep cable runs under 70 meters from the IDF to the office

Question 16

Straight-through Patch cables

Answer 16

Contains the exact same pinout on both ends of the cable
▪ T-568B is the preferred standard for wiring a building if no pre-existing
pattern is used
● Data Terminating Equipment (DTE)
o “Endpoint” devices that connect to a piece of data
communications equipment or DCE (e.g. laptops,
desktops, servers, and routers)
● Data Communications Equipment (DCE)
o Includes things like switches, modems, hubs, and bridges
● Connecting DTE and DCE devices
o Straight-through
▪ DTE to DCE
▪ DCE to DTE
o Crossover
▪ DTE to DTE
▪ DCE to DCE

Question 17

Crossover Cables

Answer 17

▪ Swaps the send and receive pins on the other end of the cable when the
connector and its pinout are created

Question 18

Pinouts (568A/568B)

Answer 18

▪ TIA/EIA-568A and TIA/EIA-568B are standard
▪ Orange and Green pairs swap

Question 19

Medium Dependent Interface Crossover (MDIX)

Answer 19

An automated way to electronically simulate a crossover cable connector
even if using a straight-through patch cable
▪ If a switch doesn’t support MDIX, use a crossover cable to make them talk

Question 20

Plenum and Non-Plenum Cable

Answer 20

▪ Plenum Cable
o A special coating put on a UTP or an STP cable that
provides a fire-retardant chemical layer to the outer
insulating jacket
o Minimizes dangerous fumes if cable on fire
o Safe for use in ceilings, walls, and raised floors
▪ Non-plenum Cable
● Also known as PVC
● Normal UTP/STP rated cable
● Cannot be used in raised floors, ceilings, or walls

Question 21

Fiber Media: FIber Optic

Answer 21

▪ Uses light from an LED or laser to transmit information through a glass
fiber
● Immune to EMI
● Uses light instead of electricity
▪ Benefits:
● Greater range (many miles)
● Greater data-carrying capacity (measured in Tbps)
▪ Types:
● Multimode Fiber (MMF)
● Single-mode Fiber (SMF)

Question 22

Single-Mode Fiber (SMF)

Answer 22

▪ Used for longer distances and has smaller core size which allows for only
a single mode of travel for the light signal
▪ SMF’s core size is 8.3-10µ in diameter

Question 23

Multimode Fiber (MMF)

Answer 23

Used for shorter distances and has larger core size which allows for
multiple modes of travel for the light signal
▪ MMF’s core size is 50-100µ in diameter
▪ Up to 2 kms or less

Question 24

Wavelength Division Multiplexing (WDM)

Answer 24

Combines multiple signals into one signal and sends over a single fiber
optic strand using different wavelengths of the laser light source

Question 25

Transceivers: Copper vs. fFiber optic cables

Answer 25

▪ Fiber-Optic Advantages ● Higher bandwidth ● Longer distances ● Immune to EMI ● Better security ▪ Copper Advantages ● Less expensive ● Easy to install ● Inexpensive tools

Question 26

Media Converters

Answer 26

▪ Convert media from one format to another ▪ Layer 1 device ● Physical conversion of signal only ▪ Examples: ● Ethernet to Fiber Optic ● Fiber Optic to Ethernet ● Coaxial to Fiber ● Fiber to Coaxial

Question 27

Transceivers

Answer 27

Device that sends (transmits) and receives data

Question 28

Bidirectional

Answer 28

o Devices take turns communicating o Known as half-duplex

Question 29

Duplex

Answer 29

Full duplex occurs when devices can both communicate at the same time o Half duplex occurs when devices can either transmit or receive, but cannot do both at the same time

Question 30

Transceivers used in switches/routers: GBIC

Answer 30

Standard, hot-pluggable gigabit Ethernet transceiver (copper or fiber)

Question 31

Small Form-factor Pluggable (SFP)

Answer 31

Compact, hot-pluggable optical module transceiver ▪ Support up to 4.25 Gbps ▪ Known as Mini-GBIC

Question 32

SFP+

Answer 32

Enhanced SFP ▪ Support up to 16 Gbps

Question 33

Quad Small Form-factor Pluggable (QSFP)

Answer 33

Compact, hot-pluggable optical module transceiver ▪ Supports up to 100 Gbps

Question 34

Cable Distribution

Answer 34

An organized system to connect the network’s backbone in the main distribution frame to the intermediate distribution frames and finally to the end user’s wall jacks

Question 35

Cable Distribution System

Answer 35

▪ Use an organized system that is hierarchical ● Demarcation point o The entrance facilities where you WAN connection will enter your building ▪ Components ● Entrance ● Cross-connect facilities ● IDF ● Backbone wiring ● Telecommunications closet ● Horizontal wiring ● Patch Panels ● Work area

Question 36

Patch Panels (Copper)

Answer 36

▪ Device with jacks to connect wiring from the jack to a network switch in a flexible manner ▪ Has punch downs (like a 110 block) on the back side that is used to connect wiring to wall jacks in building ▪ Front has RJ-45 jacks

Question 37

Patch Panels (Fiber)

Answer 37

▪ Connect fiber jacks throughout building to a single patch panel in network closet ▪ Front uses patch cables to connect different wall jacks and switch ports