02 - Cabling and Topology

Question 1

Network Topology

Answer 1

The way that cables and other pieces of hardware connect to one another

Question 2

Bus Topology

Answer 2

• used a single cable that connected all computers in a line
• data went out on whole bus
• needed termination at each end to prevent signal reflection
• a break removed the termination and causes signal reflection

Question 3

Ring Topology

Answer 3

• connected all computers on a network with a ring of cable
• data moved in a circle from one computer to the next in the same direction
• no termination needed
• a break will break the circuit, stopping data flow

Question 4

Star Topology

Answer 4

• all computers connect to a central box

- offered fault tolerance, if there was a break the other computers could still communicate

Question 5

Physical topology

Answer 5

How the cables physically look

Question 6

logical topology

Answer 6

how the signals travel electronically (signalling topology)

Question 7

Hybrid Topology

Answer 7

Any form of networking that combines a physical topology with a signaling topology

Question 8

Topology used today

Answer 8

Star-Bus

Question 9

Mesh Topology

Answer 9

wireless network, every computer connects to every other computer via two or more routes

Question 10

Partially Meshed Topology

Answer 10

at least two machines have redundant connections

Question 11

Fully Meshed Topology

Answer 11

Every computer connects directly to every other computer

Question 12

Coaxial Cable

Answer 12

• central conductor (usually copper)
• surrounded by an insulating material
• surrounded by a braided metal shield
• surrounded by a jacket
• center wire and braided metal shield share the same axis
• shields data transmissions from interference

Question 13

EMI

Answer 13

Electromagnetic Interference

- can shut down a network because it is easily misinterpreted as a signal by devices like NICs

Question 14

Coaxial connectors

Answer 14

• BNC - bayonet style

- F-type (screw on connector)

Question 15

RG-59

Answer 15

• coaxial cable primarily used for cable television
• 75 ohms
• f-type connector

Question 16

RG-6

Answer 16

• used for networking
• 75 ohms
• f-type connector

Question 17

RG-58

Answer 17

• older cable
• 50 ohms
• BNC connector

Question 18

Why use twisted pair?

Answer 18

• wire is twisted to prevent crosstalk

- the more twists per foot, the less crosstalk

Question 19

STP

Answer 19

Shielded Twisted Pair

- shielding protects from EMI

Question 20

Why use STP over UTP?

Answer 20

use STP in high EMI environments

Question 21

Cat Ratings

Answer 21

• indicates the highest frequency the cable can handle

- rated in megahertz (MHz)

Question 22

CAT 3

Answer 22

• 16 MHz

- 16 Mbps

Question 23

CAT 5

Answer 23

• 100 MHz

- 100 Mbps

Question 24

CAT 5e

Answer 24

• 100 MHz
• 1 Gbps
• most common today

Question 25

CAT 6

Answer 25

- 250 MHz | - 10 Gbps

Question 26

CAT 6a

Answer 26

- 500 MHz | - 10 Gbps

Question 27

CAT 7

Answer 27

- 600 MHz | - 10+ Gbps

Question 28

RJ-11

Answer 28

- telephone wires | - 2 pairs UTP

Question 29

RJ-45

Answer 29

- network wires | - 4 pairs

Question 30

Fiber-optic benefits

Answer 30

- not effected by EMI | - long-distance transmissions

Question 31

Fiber-optic Cable

Answer 31

- core - the glass fiber - cladding - makes the light reflect down the core - buffer - gives wire strength - insulating jacket

Question 32

How are fiber-optic cables meausred?

Answer 32

- core/cladding size | - in micrometers

Question 33

Duplex Cable

Answer 33

two pairs of fiber-optic wires fused together, one for sending and one for recieving

Question 34

MMF Cable

Answer 34

Multimode Fiber - uses LEDs as light source - 850 nanometer wavelength

Question 35

SMF Cable

Answer 35

Singlemode Fiber - uses lasers as light source - prevents modal distortion - 1310 or 1550 nanometer wavelength

Question 36

Modal Distortion

Answer 36

signals sent at the same time don't arrive at the same time because the path differ slightly in length

Question 37

Fiber Optic Connectors

Answer 37

- ST - (snap and twist) - SC - (stick and click) - LC - duplex (little connector) - MT-RJ - duplex

Question 38

DB-9 connector

Answer 38

- serial 9-pin | - 56 kbps

Question 39

DB-25 connector

Answer 39

- parallel 25-pin | - 2 Mbps

Question 40

Cable and Fire Ratings

Answer 40

PVC - no protection from smoke and fumes Riser - for vertical runs, some protection Plenum - more protection than riser