Ch 5: Ethernet (802.3)

In large Ethernet networks, there can be ________ possible data links between two hosts.

1

CAT 5e and CAT 6 wiring can carry Ethernet traffic 100 meters up to ________.

1 Gbps

The 802.11ac Wi-Fi standard uses 256 states. How many bits can it send per clock cycle?

8

________ links connect users to workgroup switches.

Access

Ethernet standards are specified at the ________ layer. A) physical B) data link C) both A and B D) neither A nor B

C) both A and B

________ describe light entering a fiber's core at different angles.

Different modes

Trunk links connect switches to ________ switches.

core

The ability to transmit in two directions simultaneously is ________.

full-duplex communication

Physical layer standards govern ________.

signaling

If you can span the distance between two switches with either a single optical fiber link or two UTP lengths with an intermediate switch, which should you choose?

single optical fiber link

What is binary 0000 in hex?

0

How long (in milliseconds) is a clock cycle if I transmit 400 Mbps with four states?

0.000005

If you double the number of states, you can transmit ________ more bit(s) per clock cycle.

1

How many wires are there is a UTP Ethernet cord?

8

To prevent an unauthorized user from sending supervisory commands to switches, companies use ________.

802.1AE

All Ethernet switches are manageable.

False

What is the quality designator for multimode optical fiber?

OM

4-pair UTP terminates in a(n) ________ connector.

RJ-45

In this book, we use the terms Ethernet and 802.3 interchangeably.

True

________ links connect switches to other switches.

Trunk

Which of the following provides security in Ethernet?

VLANs

In optical fiber, light travels through the ________.

core

What type of switch connects switches to other switches?

core switches

Optical fiber cords typically have two fiber strands. This is done to allow ________.

full-duplex operation

Ethernet has reliability issues because of its ________.

hierarchical organization

In Ethernet, switches are organized in a ________.

hierarchy

A local area network operates ________.

on a customer premises

In 4-pair UTP, what is twisted?

pairs of wires

At what layer is the 100BASE-TX standard?

physical

Ethernet standards are specified at the ________ layer.

physical

UTP and fiber distance limits are for ________.

physical links

The two tag frames provide information about ________.

priority

The longest transmission distances are possible with ________.

single-mode fiber

The main benefit of parallel transmission over serial transmission is ________.

speed

In binary signaling, there is (are) ________ state(s).

two

What is F hex in binary?

1111

The switch knows the type of device it is forwarding a frame to.

False

Ethernet addresses were formerly called ________ addresses.

MAC

________ occurs when the light energies of two pulses arrive at the far end at overlapping times.

Modal dispersion

To manage their Ethernet networks, companies rely on ________.

SNMP

ARP cache poisoning is ________.

a man-in-the middle attack

Ethernet messages are ________.

frames

Ethernet became the dominant LAN technology because of ________.

low cost

What problem limits transmission distance in 4-pair UTP?

radiation

Having only a single possible path between devices ________.

reduces switching cost

The PAD field is added by the ________ if the frame is too short without it.

sender

For what specific purpose were the 2.5GBASE-T and 5GBASE-T standards developed?

serving access points

Signal state is held constant in a clock cycle ________.

to make it easier for the receiver to sample the state

What is binary 0010 in hex?

2

A system with 16 states can transmit ________ bits per clock cycle

4

Which core diameter is used in multimode fiber.

50 microns

Which UTP quality levels can send signals at 10 gigabits per second? A) category 6 B) category 6A C) both A and B D) neither A nor B

C) both A and B

________ fiber is being sold today.

OM4

In digital signaling, there is (are) ________ state(s).

a small number of

850 nm multimode fiber is used in LANs ________.

to keep cost low

What type of switch connects users to the network?

workgroup switches

What is 9 hex in binary?

1001

Two switches that are 200 m apart at a speed of 20 Gbps should be connected using ________.

10GBASE-SR with bonding

What is binary 1111 in hex?

15

To transmit five bits per clock cycle, you must have ________ states.

16

If a physical link can use either 4-pair UTP, multimode fiber, or single-mode fiber, which should I use?

4-pair UTP

What type of copper wiring is widely used in Ethernet?

4-pair UTP

To transmit three bits per clock cycle, you must have ________ states.

8

To prevent anyone from simply walking up to a corporate switch and plugging their computer into its Ethernet port, companies can use ________.

802.1X

What 802 Working Group creates Ethernet standards?

802.3

Which light wavelength dominates in LANs?

850 nm

Which of the following is used most often in LANs for fiber transmission links?

850 nm multimode fiber

Physical layer standards govern ________. A) signaling B) physical connectors C) both A and B D) neither A nor B

C) both A and B

RSTP ________. A) can increase reliability B) was created to break accidental loops C) both A and B D) neither A nor B

C) both A and B

EUI-48 addresses in expressed in hexadecimal notation if used by ________. A) switches B) routers C) both A and B D) neither A nor B

D) neither A nor B

Ethernet standards are specified at the ________ layer. A) Internet B) transport C) both A and B D) neither A nor B

D) neither A nor B

Which of the following letters may appear in EUI-48 addresses? A) D B) H C) both A and B D) neither A nor B

D) neither A nor B

Four-pair UTP uses ________ connectors. A) universal B) binary C) ST or SC D) none of the above

D) none of the above

________ is the official name for Ethernet addresses.

EUI-48

The ARP cache gives the ________ of a router the host will send a packet to.

EUI-48 address

After an ARP cache poisoning attack, the ARP cache gives the ________.

EUI-48 address of the router the MITM attacker

A switch knows the entire data link between the source and destination hosts.

False

What organization (most specifically) creates Ethernet standards?

IEEE

The strength of a wave is its ________.

amplitude

Which UTP quality levels are needed to send signals 100 meters at 10 gigabits per second?

category 6A

The path a message takes from the source host to the destination device in an Ethernet network is a ________.

data link

To span the distance between two switches, why is adding an intermediate switch not an attractive choice?

expense

Optical fiber cords use two strands ________.

for full-duplex transmission

Using RSTP to provide backup links in Ethernet ________.

is challenging

Modal dispersion limits transmission distance in ________.

multimode fiber

Which of the following is used most often in LANs for fiber transmission links?

multimode fiber

UTP categories rate the ________ of UTP cabling.

quality

Fiber that has a core diameter of 8.3 microns is ________.

single-mode fiber

Ethernet forwarding devices are ________.

switches

When a user attempts to plug into an Ethernet switch protected by 802.1X, ________.

the user will be required to authenticate himself or herself

The distance between two corresponding points in adjacent cycles is the ________.

wavelength