4.1-4.4

Question 1

(CSMA/CD) IEEE 802.3 standard What does the acronym stand for?

Answer 1

Carrier Sense, Multiple Access/Collision Detection.

Question 2

By CSMA how does a device determine when it’s ok to send data?

Answer 2

a device listens to the transmission medium to determine whether it is free before sending data (carrier sense).

Question 3

By CSMA what happens if a device finds that the network is not free

Answer 3

the device waits a random amount of time and listens to the transmission medium again. If it is free, the device transmits its message.

Question 4

3) Media Access Method- Both devices wait a random length of time before

Answer 4

attempting to resend the original message (backoff).

Question 5

Half- Duplex Facts

Answer 5

• Collision detection is turned on.
• The device can send or receive in only one direction at a time

Question 6

Devices connected to a hub must use

Answer 6

half- duplex communication.

Question 7

Half- Duplex Speed (Bandwidth)

Answer 7

Up to the rated bandwidth (100 Mbps for 100BaseT and so on.

Question 8

Full- Duplex Facts

Answer 8

• Collision detection is turned off.
• The device can send and receive at the same time.

Question 9

Full- Duplex Speed (Bandwidth)

Answer 9

Double the rated bandwidth (200 Mbps for 100BaseT and so on.)

Question 10

A frame is a

Answer 10

unit of data that is ready to be sent on the network medium.

Question 11

The 100BASE-TX standard refers to Fast Ethernet working over

Bandwidth? Cable Type? Max Length?

Answer 11

Cat 5 (or higher) Unshielded Twisted Pair (UTP) copper cable with a maximum supported link length of 100m (328 feet) and bandwidth of 100Mbps

Question 12

1000BaseSX (short)/ GigaBit Ethernet

Bandwidth? Cable Type? Max Length?

Answer 12

Bandwidth: 1,000 Mbps (half duplex); 2,000 Mbps (full duplex)

Cable Type: Fiber Optic

Max Length: 220 to 550 meters depending on cable quality

Question 13

1000BaseLX/GigaBit Ethernet

Bandwidth? Cable Type? Max Length?

Answer 13

Bandwidth: 1,000 Mbps (half duplex); 2,000 Mbps (full duplex)

Cable Type: Fiber Optic

Max Length: 5km

Question 14

A straight-through cable connects each wire to the same

Answer 14

pin on each connector (pin 1 to pin 1, pin 2 to pin 2, etc.).

Question 15

A straight-through cable is used when

Answer 15

the crossover is performed with a hub or a switch.

Question 16

Use a straight-through cable when connecting the following devices: (2)

Answer 16

• Workstation/Router to a regular port on a hub or a switch
• Regular port on a hub or switch to an uplink port on a hub or a switch

Question 17

A crossover cable matches the

Answer 17

transmit (Tx) wires on one connector with the receive (Rx) wires on the other connector.

Question 18

A crossover cable is used when crossing is

Answer 18

not performed automatically or when crossover is performed twice.

Question 19

Use a crossover cable when connecting the following devices: (2)

Answer 19

• Workstation to a workstation, router to a router, or workstation to a router (in a back-to-back configuration)
• Uplink port on a hub or switch to an uplink port on a hub or a switch

Question 20

Use a crossover cable when connecting two like devices, and use a straight-through cable when….

Answer 20

connecting different devices or port types

Question 21

A break in the network bus means

Answer 21

that the end of the network bus is no longer terminated.

aka no devices can communicate.

Question 22

A break in the ring means (2)

Answer 22

• messages can only travel in one direction (downstream) to the break.
• Computers can send messages downstream to other devices, but cannot receive any responses because of the break.

Question 23

Causes of Unlit Network Light (4)

Answer 23

• Bad NIC
• Faulty cable
• A missing device or unplugged cable
• Switch or hub port turned off or bad

Question 24

Red/Amber Network Light Means

Answer 24

the NIC has detected a signal, but the signal is not what was expected.

Question 25

Causes of Red/Amber Network Light

Answer 25

Faulty transceiver on the NIC or remote device Incorrectly configured network cabling Incompatible networking standard

Question 26

On some switches, an amber link light indicates a slower

Answer 26

connection (such as a 100 Mbps connection instead of a a 1000 Mbps connection, which might show a green light).

Question 27

The Activity light flashes periodically even if you are not currently sending data this is known as…

Answer 27

a heartbeat or keepalive signal that lets the NIC know it has an active connection.)

Question 28

There should be at least some periods of little or no activity. A constantly flashing activity light could be caused by a faulty

Answer 28

NIC on the link that is constantly sending out data. This condition is known as chattering or jabbering.

Question 29

What happens if two devices transmit at the same time,

Answer 29

A collision occurs. Both devices wait a random length of time before attempting to resend the original message (backoff).

Question 30

Which twisted pair cable category should you use on a 1000BaseT network?

Answer 30

CAT5 cable or higher!

Question 31

What is the advantage of using single-mode cable on a 1000BaseLX network?

Answer 31

Single-mode fiber, cable runs can be up to 10 kilometers long.

Multimode fiber, it’s limited to a maximum cable length of 550 meters.

Question 32

What is the difference between 1000BaseLX and 1000BaseSX?

Answer 32

1000BASE-SX uses multimode fiber, 1000BASE-LX can use either single-mode or multimode fiber