Volume 1 - Chapter 2: Fundamentals of Ethernet LANs

Question 1

All ethernet standards fall under the scope of what IEEE designation?

Answer 1

802.3

Question 2

What is the speed of the original Ethernet standard?

Answer 2

10 Mbps

Question 3

What are the informal and formal IEEE standard names for the original Ethernet standard?

Answer 3

Informal: 10BASE-T

Formal: 802.3

Question 4

What is the speed of the fast Ethernet standard?

Answer 4

100 Mbps

Question 5

What are the informal and formal IEEE standard names for the fast Ethernet standard?

Answer 5

Informal: 802.3u

Formal: 100BASE-T

Question 6

What is the speed of the gigabit Ethernet standard?

Answer 6

1 Gbps (1000 Mbps)

Question 7

What are the informal and formal IEEE standard names for the gigabit Ethernet standard?

Answer 7

Informal: 1000BASE-LX or 1000BASE-T

Formal: 802.3z or 802.3ab

Question 8

What is the speed of the ten-gigabit Ethernet standard?

Answer 8

10 Gbps

Question 9

What are the informal and formal IEEE standard names for the ten-gigabit Ethernet standard?

Answer 9

Informal: 10GBASE-T

Formal: 802.3an

Question 10

The process of a node sending data while the other node, the receiver, using the same rules, interprets those changes is referred to as?

Answer 10

An encoding scheme

Question 11

The term “EMI” stands for?

Answer 11

Electromagnetic interference

Question 12

Define the term “crosstalk” in regards to electromagnetic interference (EMI).

Answer 12

EMI between wire pairs in the same cable

Question 13

Which Ethernet standards require 2 pairs of wires in the same cable?

Answer 13

10BASE-T and 100BASE-T

Question 14

Which Ethernet standards require 4 pairs of wires in the same cable?

Answer 14

1000BASE-T or greater

Question 15

Describe the purpose of a Gigabit Ethernet Interface Converter (GBIC).

Answer 15

The original form factor for a removable transceiver for Gigabit interfaces; larger than SFPs

Question 16

What technology is used as the replacement for GBICs?

Answer 16

The Small-Form-Factor Pluggable (SFP)

Question 17

Describe the difference between the SFP and SFP+

Answer 17

The sizes are the same, but SFP+ modules support speeds of 10 Gbps or higher

Question 18

A PC is connected to a switch via straight-through 10BASE-T or 100BASE-T cable. Which pins on the PC connect to which pins on the switch?

Answer 18

Pins 1 & 2 on the PC connect to 1 & 2 on the switch, and pins 3 & 6 on the PC connect to pins 3 & 6 on the switch

Question 19

When a PC is connected to a switch via straight-through 10BASE-T or 100BASE-T, which pins does the PC use to transmit and the switch to receive?

Answer 19

The PC uses pins 1 & 2 to transmit, and the switch receives on pins 1 & 2

Question 20

When a PC is connected to a switch via straight-through 10BASE-T or 100BASE-T, which pins does the PC use receive and the switch use to transmit?

Answer 20

The switch transmits on pins 3 & 6, and the PC receives on pins 3 & 6

Question 21

What cable is required to connect 2 nodes that use opposite pairs for transmitting data?

Answer 21

A straight-through cable

Question 22

What cable is required to connect 2 nodes that use identical pairs for transmitting data?

Answer 22

A crossover cable

Question 23

When 2 devices are connected via a crossover cable, which pairs are used for transmitting and receiving?

Answer 23

Both devices transmit on pairs 3 & 6 and both devices receive on pairs 1 & 2

Question 24

What types of devices transmit on pairs 1 & 2?

Answer 24

PCs, Routers, and Access Points

Question 25

What types of devices transmit on pairs 3 & 6?

Answer 25

Switches & hubs

Question 26

What feature was added by the IEEE to Ethernet to allow devices to detect incorrect pinouts between devices and redirect the electrical signals to the correct pairs to compensate so that the link works?

Answer 26

Auto-MDIX

Question 27

The term "auto-MDIX" stands for?

Answer 27

Automatic Medium-Dependent Interface Crossover

Question 28

What pairs on a 1000BASE-T cable are used for transmitting and receiving?

Answer 28

All pairs can be used for transmitting and receiving simultaneously. The subsequent pairs are: - 1 & 2 - 3 & 6 - 4 & 5 - 7 & 8

Question 29

What pairs on a straight-through 1000BASE-T cable are connected on each end?

Answer 29

1 & 2 to 1 & 2 3 & 6 to 3 & 6 4 & 5 to 4 & 5 7 & 8 to 7 & 8

Question 30

What pairs on a crossover 1000BASE-T cable are connected on each end?

Answer 30

1 & 2 to 3 & 6 4 & 5 to 7 & 8

Question 31

The component of a fiber cable that reflects light back into the core is referred to as?

Answer 31

The cladding

Question 32

The type of fiber cable that allows for multiple angles (modes) of light waves entering the core is referred to as?

Answer 32

Multimode

Question 33

Multimode and single-mode fiber cables use which type of light source respectively?

Answer 33

Multimode: LED Single-mode: Laser

Question 34

Describe the size and purpose of the preamble in the 802.3 header.

Answer 34

Used for synchronize data transmission, 7 bytes

Question 35

Describe the size and purpose of the SFD in the 802.3 header.

Answer 35

Start Frame Delimiter (SFD) is used to signify that the next byte begins the MAC destination address; 1 byte

Question 36

Describe the size and purpose of the type field in the 802.3 header.

Answer 36

Defines the packet inside as either IPv4 or IPv6; 2 bytes

Question 37

What is the size of the data and padding within the 802.3 frame?

Answer 37

46-1500 bytes, padding is added to meet the 46 byte minimum

Question 38

Describe the size and purpose of the FCS field in the 802.3 trailer.

Answer 38

Frame Check Sequence (FCS) is used to detect if the frame contains transmission errors; 4 bytes

Question 39

Describe the difference between half-duplex and full-duplex.

Answer 39

When sending data, half duplex devices must wait if they are currently sending data. Full duplex devices can send and receive simultaneously

Question 40

Hubs are considered to operate at what layer of TCP/IP?

Answer 40

Layer 1

Question 41

Describe the purpose of CSMA/CD.

Answer 41

Carrier Sense Multiple Access w/ Collision Detection is used to detect and recover from ethernet collisions in half-duplex networks

Question 42

Network designs that utilize network hubs and CSMA/CD are classified as?

Answer 42

Ethernet Shared Media

Question 43

Network designs that utilize network switches and full duplex are referred to as?

Answer 43

Ethernet