Cisco Chapter 4

Question 1

Business offers wireless capability, devices on a wireless network must be connected to a ????

Answer 1

Wireless access point (WAP).

Question 2

Switch devices and ????? are often two separate dedicated devices within a network implementation

Answer 2

wireless access points

Question 3

In many homes, individuals are implementing ??? .

Answer 3

home integrated service routers (ISRs)

Question 4

What does an ISRs do?

Answer 4

switching component with multiple ports,
multiple devices to be connected to the LAN using cables.
Conencts with AP(access point)

Question 5

??? connect a device to the network.

Answer 5

Network Interface Cards(NIC)

Question 6

Ethernet NICs

Answer 6

Wired connection

Question 7

WLAN (Wireless Local Area Network) NICs are used for wireless.

Answer 7

Wireless connection

Question 8

A ????? can be used to regenerate the wireless signal to other parts of the house that are too far from the wireless access poin

Answer 8

Wireless range extender

Question 9

All wireless devices must share access to the ???connecting to the wireless access point.

Answer 9

airwaves

Question 10

A wired device does not need to share its access to the network with other devices. Each wired device has a separate ??? over its Ethernet cable.

Answer 10

communications channel

Question 11

The OSI physical layer provides the means to ??? the ?? that make up a ???? frame across the network media.

Answer 11

transport/bits /data link layer

Question 12

The OSI physical layer accepts a ??? from the ??? and ?? it as a series of signals that are ?? onto the local media.

Answer 12

complete frame/data link layer/encodes/transmitted

Question 13

The OSI physical layer encoded bits that comprise a frame are received by either an ??? or an ????

Answer 13

end-device/ intermediate device.

Question 14

2: The physical layer ?? the ?? and creates the electrical, optical, or radio wave signals that represent the bits in each frame.
These ?? are then sent on the media, one at a time.

Answer 14

encodes/frames/bits /signals

Question 15

1: The user data is ?? by the transport layer, placed into ?? by the network layer, and further ?? into frames by the data link layer.

Answer 15

segmented/packets/encapsulated

Question 16

1: The user data is segmented by the ??, placed into packets by the ??, and further encapsulated into frames by the ??

Answer 16

transport layer/ transport layer/data link layer

Question 17

2: The ?? encodes the frames and creates the electrical, optical, or radio wave signals that represent the bits in each frame.
These signals are then sent on the media, one at a time.

Answer 17

physical layer

Question 18

3: The destination node ??? retrieves these individual signals from the media, restores them to their bit representations, and passes the bits up to the ?? as a complete frame.

Answer 18

physical layer/data link layer

Question 19

3: The destination node physical layer retrieves these ?? from the media, restores them to their ??, and passes the bits up to the data link layer as a ??

Answer 19

individual signals/bit representations/complete frame

Question 20

???: The signals are patterns of electrical pulses.
??: The signals are patterns of light.
??: The signals are patterns of microwave transmissions.

Answer 20

Copper cable/Fiber-optic cable/Wireless

Question 21

The services and protocols in the TCP/IP suite are defined by the

Answer 21

Internet Engineering Task Force (IETF).

Question 22

Bandwidth

Answer 22

is the capacity of a medium to carry data in a given amount of time.

measured in kilobits per second (kb/s),
megabits per second (Mb/s)
gigabits per second (Gb/s).

Bandwidth is sometimes thought of as the speed that bits travel, however this is not accurate. For example, in both 10Mb/s and 100Mb/s Ethernet, the bits are sent at the speed of electricity. The difference is the number of bits that are transmitted per second.

This all plays a role in determining the available bandwidth.
The properties of physical media
The technologies chosen for signalling/detecting network signals
Physical media properties,
current technologies,
laws of physics

Question 23

Throughput

Answer 23

Throughput is the measure of the transfer of bits across the media over a given period of time.

Due to a number of factors, throughput usually does not match the specified bandwidth in physical layer implementations. They are:

The amount of traffic
The type of traffic

In an internetwork or network with multiple segments, throughput cannot be faster than the slowest link in the path from source to destination. Even if all or most of the segments have high bandwidth, it will only take one segment in the path with low throughput to create a bottleneck to the throughput of the entire network.

There are many online speed tests that can reveal the throughput of an Internet connection. The figure provides sample results from a speed test.

There is a third measurement to assess the transfer of usable data that is known as goodput. Goodput is the measure of usable data transferred over a given period of time. Goodput is throughput minus traffic overhead for establishing sessions, acknowledgments, and encapsulation.

Question 24

Latency

Answer 24

refers to the amount of time to travel from one given point to another.

Question 25

The physical layer produces the

Answer 25

representation and groupings of bits as voltages, radio frequencies, or light pulses.

Question 26

Various standards organizations contributed to the definition of the physical, electrical, and mechanical properties of the media available for different data communications. These specifications guarantee that cables and connectors will function as anticipated with different data link layer implementations.

Answer 26

As an example, standards for copper media are defined for the:

Type of copper cabling used
Bandwidth of the communication
Type of connectors used
Pinout and color codes of connections to the media
Maximum distance of the media

Question 27

Encoding

Answer 27

line encoding a method of converting a stream of data bits into a predefined “code”.
encoding is the method/ pattern used to represent digital information.
Like Morse

Question 28

The physical layer standards address ?? functional areas:

Answer 28

3

Question 29

Physical Components

Answer 29

Connectors that transmit and carry the signals to represent the bits that are all specified in standards associated with the physical layer

Question 30

Signaling

Answer 30

The physical layer generates the electrical, optical, wireless signals that represent “1” and “0” on the media.
The method of representing the bits is called the signalling method.
The physical layer standards must define what type of signal represents a “1” and what type of signal represents a “0”. This can be as simple as a change in the level of an electrical signal or optical pulse. For example, a long pulse might represent a 1 whereas a short pulse represents a 0.

This is similar to the signalling method used in Morse code, which may use a series of on-off tones, lights, or clicks to send text over telephone wires or between ships at sea.

There are many ways to transmit signals. A common method to send data is using modulation techniques. Modulation is the process by which the characteristic of one wave (the signal) modifies another wave (the carrier).

The nature of the actual signals representing the bits on the media will depend on the signaling method in use.

Figure 2 illustrates the how AM and FM techniques are used to send a signal

Question 31

The physical layer hardware, media, encoding, and signalling standards are defined by

Answer 31

International Organization for Standardization (ISO)
Telecommunications Industry Association/Electronic Industries Association (TIA/EIA)
International Telecommunication Union (ITU)
American National Standards Institute (ANSI)
Institute of Electrical and Electronics Engineers (IEEE)
National telecommunications regulatory authorities including the Federal Communication Commission (FCC) in the USA and the European Telecommunications Standards Institute (ETSI)

Question 32

Regional cabling standards groups

Answer 32

CSA (Canadian Standards Association), CENELEC (European Committee for Electrotechnical Standardization), and JSA/JIS (Japanese Standards Association), developing local specifications.

Question 33

Manchester encoding represents a 0 bit by a high to low voltage transition, and a 1 bit is represented as a low to high voltage transition

Answer 33

The transition occurs at the middle of each bit period. This type of encoding is used in 10 b/s Ethernet. Faster data rates require more complex encoding and is used in older Ethernet standards

Question 34

Throughput

Answer 34

the measure of the transfer of bit’s across the media

Question 35

Bandwith

Answer 35

The capacity of a medium to carry data

Question 36

Wireless

Answer 36

A pattern of microwaves to represent bits

Question 37

Copper cable

Answer 37

\+ electrical pulses
\+inexpensive
\+easy to install, 
\+low resistance to electrical current
- limited by distance 
- signal interference.

Question 38

signal attenuation

Answer 38

The longer the signal travels, the more it deteriorates.

Question 39

Electromagnetic interference (EMI)
 radio frequency interference (RFI)

Answer 39

EMI and RFI signals can distort and corrupt the data signals being carried by copper media. Potential sources of EMI and RFI include radio waves and electromagnetic devices, such as fluorescent lights or electric motors.

Question 40

Crosstalk

Answer 40

• Crosstalk is a disturbance caused by the electric or magnetic fields of a signal on one wire to the signal in an adjacent wire. In telephone circuits, crosstalk can result in hearing part of another voice conversation from an adjacent circuit. Specifically, when an electrical current flows through a wire, it creates a small, circular magnetic field around the wire, which can be picked up by an adjacent wire.

Question 41

To counter the negative effects of crosstalk,

Answer 41

copper cables have opposing circuit wire pairs twisted together, which effectively cancels the crosstalk.
Select the cable type or category most suited to a networking environment.
Designing a cable infrastructure to avoid known and potential sources of interference in the building structure.
Using cabling techniques that include the proper handling and termination of the cables.

Question 42

There are 3 types of copper media used in networking

Answer 42

Unshielded Twisted-Pair (UTP)
Shielded Twisted-Pair (STP)
Coaxial

Question 43

Coper cables are used to interconnect nodes

These standards specify the mechanical dimensions of the connectors and the acceptable electrical properties of each type.

Answer 43

Each type of connection/accompanying devices has cabling requirements stipulated by physical layer standards.

Networking media use modular jacks and plugs to provide easy connection and disconnection
A single type of physical connector may be used for multiple types of connections.