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