Explaining Properties of Network Traffic

Question 1

What are Signaling and Modulation

Answer 1

Cabled media (bounded)
* Copper (electrical)
* Fiber optic (light waves)
* Wireless media (unbounded)
* Radio waves
* Digital data: discrete binary values
* Digital signaling
* Line coding (discrete pulses)
*
Example: high (1) vs. low (0) voltage on wire (actual schemes are more complex)

Analog sampling for transport over digital channels

Question 2

Explain Bandwith and give all points of bandwidth

Answer 2

Bandwidth
* Range of frequencies available
* Baseband transmission uses whole bandwidth of media
* Multiplexing – time or frequency division
* Channel capacity
* Cycles per second measured in hertz (Hz)
* Multiples – megahertz (MHz) and gigahertz (GHz)
* Data rate

Question 3

What is Baud rate

Answer 3

Baud is a common unit of measurement of symbol rate, which is one of the components that determine the speed of communication over a data channel. It is the unit for symbol rate or modulation rate in symbols per second or pulses per second.

Question 4

What is Baud rate

Answer 4

Baud is a common unit of measurement of symbol rate, which is one of the components that determine the speed of communication over a data channel. It is the unit for symbol rate or modulation rate in symbols per second or pulses per second.

Question 5

What is Bit Rate

Answer 5

The number of bits per second that can be transmitted along a digital network.

Question 6

Explain Attenution

Answer 6

Loss of signal strength measured in decibels (dB)
* Ratio of signal strength at source to signal strength at destination

Question 7

Explain Noise

Answer 7

Stray or unwanted signals interfering with the intended signal
* Signal-to-noise ratio (SNR)

Question 8

Give a description of copper cable

Answer 8

Copper cable
* Low voltage electrical circuit
* Twisted pair and coaxial (coax) types
* Subject to high attenuation and interference

Question 9

Give a description of fiber optic cable

Answer 9

Fiber optic cable
* Light signals
* Less susceptible to attenuation and interference

Question 10

Give a description of wireless radio

Answer 10

Wireless radio
* RF (radio frequency) waves propagating between sending and reception antennas
* Limitations on RF usage and power output affect range
* Industrial, Scientific, and Medical (ISM) frequency bands (2.4 GHz and 5 GHz)
* Susceptible to interference

Question 11

Give a description of deterministic media access

Answer 11

Deterministic media access
* Token-passing
* Benefits real-time systems

Question 12

Give all the points contention

Answer 12

Contention
* Collision domains
* Collisions increase and performance decreases as more nodes are added

Question 13

Explain CSMA

Answer 13

Carrier sense multiple access (CSMA)
* Half-duplex
* CSMA/CD (with collision detection)
* CSMA/CA (with collision avoidance)

Question 14

Give a description of switched networks

Answer 14

Switched networks
* Eliminate effect of collisions
* Each port is a separate collision domain
* Full duplex

Question 15

Explain full duplex

Answer 15

Full-duplex data transmission means that data can be transmitted in both directions on a signal carrier at the same time

Question 16

Give the process of CSMA/CD, CSMA/CA, and Switching

Answer 16

1. Data to transmit
2. Check networking
3. Transmit Data
4. Collision
5. Wait
6. Retransmit data

Question 17

Give a full description of broadcast domains

Answer 17

Unicast versus broadcast traffic
* Broadcast domain boundaries
* Established by routers at layer 3.
* Bridges and switches normally flood
broadcast traffic.
* Virtual LANs (VLANs) can be used
to isolate switch ports to separate
broadcast domains.

Question 18

Give a description of Ethernet frame format

Answer 18

Ethernet
Principal wired LAN technology
Logical bus topology (but typically physical star)
Preamble
Addressing
Destination and source Media Access Control (MAC) addresses
48-bit (6 byte)

Question 19

Explain Unicast fully

Answer 19

Unicast – The frame is directed to a single destination interface.
In shared Ethernet, all interfaces receive the frame, but ignore it if it is not addressed to them.
In switched Ethernet, the switch identifies the appropriate port to use to deliver the frame.

Question 20

Explain broadcast fully

Answer 20

Broadcast – The frame is directed at every interface in the same broadcast domain.
Hubs and switches flood broadcasts to every port (other than the source port).
Frame uses the destination MAC address ff:ff:ff:ff:ff:ff.

Question 21

Explain error checking

Answer 21

Error checking
Cyclic Redundancy Check (CRC)/Frame Check Sequence (FCS)
No retransmission or error correction

Question 22

What is MTU and frame length

Answer 22

Frame length and Maximum Transmission Unit (MTU)
Payload size
Coding payload type
Minimum frame length
Jumbo frames

Question 23

Give all Ethernet deployment standards and how its measured

Answer 23

xBASE-y convention
Bit rate
Baseband/broadband transmission
Media type

1. 10BASE-T
2. 100BASE-x (Fast Ethernet)
3. 1000BASe-T (Gigabit Ethernet)
4. 10 Gigabit Ethernet (10GbE)