EECE 233 Final
bit
The pdu (protocol data unit) at the physical layer is what? #10 a.packet b.bit c.frame d.message e.none
True/False - A car battery, motor, and a microphone are examples of transducers.
True
True/False - At the federal level, FCC jurisdiction covers all communications that is between states or that is into and out of the United States or has the potential to cross state lines or into out of the United States?
True
True/False - Encapsulation and DeEncapsulation is a function OSI Layers in the Layered Model of data communications.
True
True/False - Multiplexing and Demultiplexing is a function of OSI Layers in the Layered Model of data communications.
True
True/False - QAM modulation combines a number of phases with a number of amplitudes in combination to send multiple bits per baud noise.
True
True/False - Sectoring promotes freqency reuse.
True
True/False - Single mode fiber suffers from chromatic dispersion but not modal dispersion.
True
True/False - The Telecommunications Act of 1996 was intended to modernize federal telecommunications regulations so that more competition was promoted in the telecommunications industry?
True
True/False - The radio portion of the electromagnetic spectrum is in a lower frequency band than that associated with the visual light band?
True
True/False - VOIP can be used to carry telephone trunks
True
True/False - With frequency modulation, the receiver can better discriminate between the actual signal and the noise, since noise usually affects the amplitude of the incoming signal. FLIP FLIP FLIP FLIP
True
With half-duplex communications, communications takes place how? a. Only in one direction. b. In both directions, but only one direction at a time. c. Simultaneously in both directions. d. In one direction some times, and both directions at other times. e. None of the above.
b (in both directions, but only one direction at a time)
The combo trunks consider the busy hour outbound calls, as well as the busy hour inbound to the main number The DID trunks take consider the number of inbound calls from outside the system to someone's desk The amount of voicemail lines considers the amount of call traffic of the main number, the inbound DID calls, and the busy internal. To get the max traffic, you multiply the amount of calls during the busy hour times the average holding time
combo trunks vs did trunks vs voicemail line calculations
low bandwidth and latency or delay
digital video broadcasts are detrimnetlaly sensitive to what? 18
Notes - Encapulation and multiplexing in osi layered model for hw application transport network data link physical - Physical - Data link - Network - Transport - Session - Presentation - Application Comp a - Router box contains data link functions, physical connections, but also contains applications ○ Router box contains other applications, such as telnet, SSH - secure cell login and actually login into a machine that way, FTP - file transfer protocol ○ Router as computer vs laptop - a router can be a host on more than one network at the same time where a computer is generally a host of a single network at one time § Must be a host, because it must be able to speak on all networks it is connected to § Router must have a configuration profile ○ Why are we multiplexing - § Say we have an email app and web browser app § Both apps use the transport layer function § Email app - email message, adress, header, and chop it up into packets(group of bits in format) packet has a header and a payload - payload contains email message, subject and email adress, the header contains where it is supposed to go to § Computer b has the gmail post office server § Header has a location, the name of the machine - machine name is an ip adress § TCP hands transport layer to the layer below - encapsulation □ Sort tcp email messages from tcp web browser messages by looking at the port numbers □ So network layer is running the IP □ Payload section where running ip contains entire tcp packet and its header □ Ip in the network layer doesn't care about tcp header or its contents □ Application cares about the content □ Tcp(transprt) doesn't care about the content, it just knows it has to get an email somewhere, □ Ip doesn't care(network) just gotta get to an ip adress somewhere □ Purpose of encapsulation is to funciton simply and fast and not worry about layer above them that handed the information to them □ Tcp packet totally encapsualted within paylod of ip packet □ IP uses DNS or cache to use as the destination adress in the packet header □ Source ip adress - adress you are sending the email from □ Email has different tcp packets than web adress □ Header in tcp packet contains port number, information describing the type of service, order etc. □ Multiplexing occurs because email and web browser are using tcp □ Both using data flow into one common data stream (tcp level - stream of tcp packets) □ Some pacets contain email and some contain web browsing adress □ Look at the well known ports, □ Sniffer can read unencrypted emails □ Ip header- destination adress and source ip adress, but also have source order ® Ip is doing netowrk layer function □ From network layer to data link layer, it is handed to the payload of the frame, the header for the frame contains the mac adress, because it is going to the data link layer network □ Source mac adress- sending email, destination mac adress- the router □ Default gateway - if youre on a local network, the server is not on your local network, assume it is on gmail □ Your operating system has a default gateway ip adress and a mask, tells you which portion is network adress and which is the host, if ip adress does not match network prefix after mask is applied, it knows it needs to do an arp -adress resolution protocol, asks for default gateway mac adress □ Ip adress is encapsulated in the payload, but in mean time, it snatched default gateway ip adress with the arp, and it put the routers mac adress in the frame, and sent the frame to the router □ Ethernet will not transport ip packets without ethernet frames taken care of data link layer □ Physical layer is collected at the router is handed up the data link layer in the router where is composes the frame of the bits □ Frame contains source adress, mac adress came from and mac adress of router port it his coming in □ This is all in the roiter □ Frame opens up into its own payload and looks at the ip packet, the ip packet is handed to the network layer, the network layer looks at the ip adress to see the post office it is going to, the network layer has a routing funciton, looks at ip adress at the packet and says how do I get this ip packet to its destination, (deencapsulation) □ To get to physical layer of computer b from the router, the process reverses itself and encapsulate into another frame where the destination adress knows port of router It must go out of and what machine on that network, encapulsate out the stack to get out back to its destination □ Once it gets to physical layer, takes bits into fiber obtic light pulses and sends to destinaiton adress and deencapsualte again □ Gets to transport layer and looks at tcp port, and look what application it ends to Demultiplexinfg and multiplexing can occur from any layer to any other layer □ Multiplexing - layers above us same function as layers below to compose common stream □ Demultiplexing - sorting common stream of layer above where it has to go
encapuslation and demultiplexing in osi layer
Simplex - communications in one direction Half duplex - communications in both directions but only one at a time Full duplex - communication in both directions at the same time
explain the three means of communication protocols?
§ Email app - email message, adress, header, and chop it up into packets(group of bits in format) packet has a header and a payload - payload contains email message, subject and email adress, the header contains where it is supposed to go to TCP hands transport layer to the layer below - encapsulation □ Ip header- destination adress and source ip adress, but also have source order ® Ip is doing netowrk layer function □ From network layer to data link layer, it is handed to the payload of the frame, the header for the frame contains the mac adress, because it is going to the data link layer network
explain what process happen in which layers of osi layered mode
hold time * averae number of calls /3600
how to calculate traffic in erlangs?
to avoid aliasing of a signal, you need to sample at the rate of at least twice the highest frequency contained in the signal
nyquist rate
Longer run before it fails first time, the more reliable it is(create redundancy) availability = how long a system is up vs down - decrease mttr
reliability vs availability
A smart trunk can carry how many digitized phone calls? a. 23 b. 16 c. 10 d. 24 e. 25 f. 0 g. None of the above
A (23)
A PBX is meant to do what? Choose the best answer. a. Allow a greater number of calls to be statistically handled with fewer trunks. b. Make sure all phone lines connect to the central office c. Improve data throughput by reducing collisions d. Eliminate the racetrack effect. e. Make it possible to do long distance calls f. None of the above
A (Allow a greater number of calls to be statistically handled with fewer trunks)
Present in single mode fiber a. Chromatic dispersion b. Modal dispersion c. Post tensioning d. Prism amplification e. None of the above
A (Chromatic dispersion)
Analog to digital conversion is important for what reasons? a. Computers and networks are digital as this makes information easier to transmit and process, but most information to be sensed in the physical world is analog in nature. b. Computers require analog information. c. Networks require analog information d. Data storage is inherently analog e. None of the above
A (Computers and networks are digital as this makes information easier to transmit and process, but most information to be sensed in the physical world is analog in nature)
Modulation is the technique whereby an information signal (ie baseband signal) is used to modify a carrier signal in such a way as to encode the baseband signal's information onto the carrier for later extraction at the receiver which extracts the baseband signal through a demodulation process. Combining modulated signals at different frequencies onto the same channel is one example of a useful technique called broadband communications. But why is broadband communications advantageous? a. It allows multiple baseband information signals to share a common medium and for the receiver to select any one or more of them for receiving b. It allows the channel to deliver information with fewer bit errors. c. It allows the channel to deliver information with less latency d. It allows Huffman compression in the channel e. None of the above
A (It allows multiple baseband information signals to share a common medium and for the receiver to select any one or more of them for receiving)
Who archived the first US patent on a device we now generally know as the telegraph? a. Samuel Morse b. Bill Gates c. Alexander Bell d. Steve Jobs e. None of the above
A (Samuel Morse)
If the mean time to repair a system decreases given the system maintains a constant failure rate, what impact will result for the system? a. System availability will increase. b. System reliaility will decrease. c. System reliability will increase. d. On average the system may experience fewer failures. e. System availability will decrease. f. A & B g. C & D h. D & E i. none of the above
A (System availability will increase)
In the TCP/IP version of the OSI Model, this helps to handle flow control, missing packets, and packets arriving out of order. a. TCP b. MAC addresses c. Multiplexing d. Encapsulation e. NAT f. MAC frames g. None of the above
A (TCP)
A concept where by the value of information to the receiver depends on just when information is received is known as what? a. TVI - the time value of information b. JTA - the concept of just in time arrival c. CVD - the concept value of data d. ETL - the concept of the essential time limit e. None of the above
A (Time value of information)
In the TCP/IP version of the OSI Model, this helps to identify the application program, e.g. email, web browser, etc. needed to recieve the packets handed up from the transport layer. a. Well-known TCP ports b. MAC addresses. c. Multiplexing d. Encapsulation e. NAT f. None of the above
A (Well-known TCP ports)
Out of the following telecommunication mediums, which has the greatest distance x bandwidth product? a. fiber b. twisted pair c. coaxial cable d. radio channel with 30 Mhz bandwidth limitation e. Telephone local loop
A (fiber)
A 256 QAM modulation scheme would allow 256 unique digital symbols to be transmitted where each symbol is made up of how many bits? a. 1 b. 8 c. 9 d. 2 e. None of the above
B (8)
Which of these has the highest bandwidth? A. A 1-kilometer length of multimode fiber. B. A 1-kilometer length of single mode fiber c. A 1-kilometer length of coaxial cable wire d. A 1-kilometer length of twisted pair wire e. A 1-kilometer length of local analog loop
B (A 1-kilometer length of single mode fiber)
The US Justice Department split of AT&T from the Bell Companies and the split of the Bell Companies from each other in 1984 is generally known as what? a. The Sherman Anti-trust Act b. Divestiture c. Sarbanes Oxley Decision d. The MCI Decision e. None of the above
B (Divestiture)
A look-ahead call placement computer network for the phone system. a. NAT b. SS7 c. Plan 9 d. TCP E. Tie Trunk f. Translation bridge g. None of the above
B (SS7)
A method for improving freqency reuse in Cellular Systems. a. Tall towers b. Sectoring c. Simulcast d. Handoff e. Air Logistics f. None of the above
B (Sectoring)
With FHSS (CDMA - spread spectrum), how does communication take place? a. A different frequency channel is used for each trunk and does not hop b. A different hopping pattern "code" is used for each trunk c. A different time slot is used for each trunk d. A different pair of wires is used for each trunk e. None of the above
B (a different hopping pattern "code" is used for each trunk)
The Telecommunications Act of 1934 is an act of congress that created what federal agency? a. The National Telecommunications Regulations Agency b. The Federal Communications Commision c. The Interstate Commerce Commision d. The Public Service Commision e. None of the above
B (the FCC)
The communications medium is also known generally as what? a. the fiber b. the channel c. the twisted pair d. the cable e. none of the above
B (the channel)
Samuel Morse's coding of the English alphabet into "Morse Code", smartly employed a method that used fewer symbols called dots and dashes for those letters that occur less frequently in the English language, and more symbols for those letters that occur more often. This type of compression is generally known as what? a. Random Linear Network Coding b. Forward Error Correction Coding c. Huffman coding d. Cyclic Redundancy Coding e. None of the above
C (Huffman coding)
You are asked to calculate the amount of telephone traffic coming out of a telephone switch to the C/O. Why is this important? a. It will tell you how many telephones you need. b. It will tell you how to locate your switch, physically. c. It will help you to determine the number of combo trunks d. It will help you determine the number of DID trunks e. It will help you determine the number of toll trunks f. none of the above
C (It will help you to determine the number of combo trunks)
A ____ address is a 12 digit HEX number. a. TCP b. IP c. MAC d. Ethernet e. NAT f. BGP g. None of the above
C (MAC)
In a PBX, records call statistics a. TCP b. IP c. SMDR d. IGRP e. NAT f. BGP g. None of the above
C (SMDR)
A high speed computer network used for look-ahead call placement. It saves actual telephone system trunks from being seized in order to just check if the called phone is busy. Select the best answer. a. Branched circuits b. SMDR c. SS7 d. Voice mail e. ISDN-PRI f. Toll Trunks g. None of the above
C (SS7)
The function of well-known ports is handled by what standard in the Transport Layer? a. IP b. Ethernet c. TCP d. IPX e. BGP f. None of the above
C (TCP)
An analog signal which has been sampled at less than the Nyquist rate for conversion to a digital signal will cause a problem called what at the receiver when it is converted back? a. Latency b. Quantization accuracy c. Aliasing d. Jitter e. None of the above
C (aliasing)
Telephone communications are detrimentally sensitive to what? a. A small amount of bit errors. b. Low bandwidth c. Latency or delay d. Discrete Cosine Transformation e. A & B f. B & C g. C & D h. none of the above
C (latency or delay) only!
PSK is a special or restricted form of what? a. Amplitude Modulation b. Frequency Modulation c. Phase Modulation d. QAM e. None of the above
C (phase modulation)
Increasing the resolution (or the number of levels) employed by the analog to digital converter increases what? A. Latency. B. Jitter c. Quantization accuracy d. Aliasing e. None of the above
C (quantization accuracy)
Modems are important nowadays for what main reason? a. Fiber optic transmission b. Cable-based transmission c. Wireless transmission d. Spread spectrum transmission e. None of the above
C (wireless transmission)
The following most clearly explains the difference between phone lines and phone trunks. a. Lines carry dc signaling while trunks carry ac signaling b. Trunks carry dc signaling while lines carry ac signaling c. Trunks connect to voice mail while lines connect to phones d. LInes connect between the switch and phones and trunks from switch to switch e. Trunks connect only long distance calls while line only local calls f. None of the above
D (Lines connect between the switch and phones and trunks from switch to switch)
This helps to find your cell phone when a call comes in. a. TCP b. IP c. Auto locator d. Auto affiliation e. NAT f. BGP g. None of the above
D (auto affiliation)
Helps to keep communications code simple and fast? a. Well-kown TCP ports b. MAC addresses c. Multiplexing d. Encapsulation e. NAT f. None of the above
D (encapsulation)
The bathtub curve depicts what? a. The general life-cycle availability for a component or system. b. The general life-cycle reliability for a component or system. c. The general life-cycle impact of redundancy d. The general life-cycle failure rate for a component or system. e. none of the above
D (the general life-cycle failure rate for a component or system
Put a nice square wave into a cable at one end and given a cable length great enough, you can get only a sinusoidal wave at the far end of the cable. Under a Layman's understanding of Fourier Analysis, the likely explanation for this is that the cable filtered out what from the original square wave? a. The fundamental b. the current c. the phase d. the harmonics e. None of the above
D (the harmonics)
A situation where a phone network, design for normal statistics, experiences large loads under abnormal statistics. a. The catch all b. the NAT c. the MAU d. the racetrack effect e. the turbo effect f. the data flood effect g. none of the above
D (the racetrack effect)
A T1 circuit can carry how many digitized phone calls? a. None b. 8 c. 10 d. 20 e. 24 f. 48 g. 96 h. 16 i. 12 j. None of the above
E (24)
b
From Fig. 2, it would be correct to say that the graph best represents (choose the best answer): A. A frequency domain graph of a Frequency Modulated carrier. B. A frequency domain graph of an Amplitude Modulated carrier. C. A frequency domain graph of a Phase Modulated carrier. D. A frequency domain graph of a Quadrature Amplitude Modulated carrier. E. A frequency domain graph of an FUSS Modulated carrier. F. A time domain graph of a Frequency Modulated carrier. G. A time domain graph of an Amplitude Modulated carrier. H. A time domain graph of a Phase Modulated carrier. I. A time domain graph of a Quadrature Amplitude Modulated carrier J. A time domain graph of an FUSS Modulated carrier. K. An example of multiplexing. L. None of the Above. M. All of the Above.
True/False - Reliability is a concept meant to express the probability in percent that a system will be found in an operative state, in other words (up time / total time) * 100%
False
True/False - The Hartley-Shannon theorem says that if a signal is to be reproduced faithfully through digital sampling, it should be sampled at twice the signal's highest frequency.
False
True/False - The term dBm is just a gain or loss and cannot actually be measured in the lab as a power level.
False
True/False - With Amplitude modulation of a carrier it is always necessary to transmit a powerful carrier.
False
True/False - With asynchronous communications the data signal is sent along with a clock signal.
False
True/False - The Telephone Network is a prime example of a connection-less network.
False internet
True/False - The Internet is a prime example of a connection-oriented network.
False telephone
Encapsulation
Question 11: (2.5 Points): In the OSI Layered model, PDUs of higher layers are put inside the payloads of the PDUs of lower layers in a process called what? A. Compression. B. Bit Stuffing. C. Multiplexing. D. Encapsulation. E. None of the above.
24000
Question 12: (2.5 Points): The highest frequency of a known signal is 6000 Hz. If a sufficient sampling rate to avoid aliasing is use, and 16 hash marks resolution is to be obtained for each sample, how many bits per second minimum must the data stream be capable of carrying? A. 6000. B. 12000. C. 24000. D. 48000.
false
Question 13: (2.5 Points): The baud rate and bit rate are always the same (true/false)? (mark answer on answer sheets only)
harmonic distortion
Question 14: (2.5 Points): Using a circuit to clip of the tops and bottoms of a sinusoid waveform signal would produce what? A. Oxley's distortion B. A digital signal C. Harmonic distortion D. Mu Law Compression E. None of the above. (mark answer on answer sheets only)
True 2^8 =256 8 bits 8000 time per second is 64000 bits per second - standard rate for voice 300 -3300 hz
Question 15: (2.5 Points): The phone company uses 8000 samples per second and 256 hash mark resolution to sample phone grade conversation in the range of 300 to 3,300 Hz, to produce a 64kbit data stream (true / false)? (mark answer on answer sheets only)
true, because you cant see radio waves
Question 16: (2.5 Points): The radio portion of the electromagnetic spectrum is in a lower frequency band than that associated with the visual light band (true / false)? (mark answer on answer sheets only) WHY?
True/False - Availability is a concept which essentially says how long the system will run until it fails the first time.
False
True/False - Digital signals do not contain noise.
False
True/False - Multimode fiber suffers from chromatic dispersion but not modal dispersion
False
The essential difference between connection-oriented and connection-less communications is that: A. With connection-oriented communications information is just sent through the network, establishing the network route hop by hop b. With connection-oriented communications, in-order arrival of transmitted packets is not guaranteed. c. with connection-oriented communications, packets can take differing paths through the network d. with connection-oriented communications, data communications more efficiently shares the network e. none of the above
E (None of the above) connection oriented - telepohne, swtich □ Follow the same path of the network for entirety of the communications( voice, data) □ Order is preserved □ Each packet has the same amount of delay (0 variance in delay - which means the change from packet to packet) □ Costs more money on a person to person basis - very expensive § Connectionless - uses router - internet □ On a mass user base, it is cheaper, more economical, and more efficient Router gets a packet and tries to determine the best route to take by determining speeds of paths, and each packet can take a different route There can be mising packets, (protocol) packets out of order, (protocol) protocols on the receiving end, variance in delay □ Shared network- efficeint economically
The POP is what? a. the post office communications protocol b. Telephone DC signaling c. SS7 d. Position of Protocol e. Point of Presence f. Toll trunks g. None of the above
E (Point of presence)
All of the following are ways to carry trunks with the exception of what? a. space division multiplexing - separate wire pair per trunk b. frequency division muliplexing - separate frequency per trunk c. time division multiplexing - separate time slot per trunk d. code division multiplexing - separate hopping code per trunk e. SS7 - trunks
E (SS7 - trunks)
Sectoring is a way to do what? a. Achieve branch circuits b. Put each phone call in a different time slot c. Do SS7 look-ahead call placement d. Partition Voice mail boxes e. It is an ISDN-PRI way of bringing in trunks f. Achieve frequency reuse g. None of the above
F (Achieve frequency reuse)
The following most clearly explains the difference between tie trunks and combo trunks. a. Lines carry dc signaling while trunks carry ac signaling b. Trunks carry dc signaling while lines carry ac signaling c. Trunks connect to voice mail while lines connect to phones d. LInes connect between the switch and phones and trunks from switch to switch e. Trunks connect only long distance calls while line only local calls f. None of the above
F (None of the above)
The following is a form of AC signaling in the telephone network? a. Loop current b. Static c. SS7 d. Voice mail e. ISDN-PRI f. Dial Tone g. None of the above
F (dial tone)
Phone lines connecting only from phone switch to phone switch? a. Branch circuits b. SMDR c. SS7 d. Voice mail e. ISDN-PRI f. Trunks g. None of the above
F (trunks)
f
From Fig. I, assume Signal A is the same information signal used to modulate both carrier signals, i.e. both Signal B and Signal C. In Figure I , it would be correct to say that Signal C is (choose the best answer): A. A frequency domain graph of a Frequency Modulated carrier. B. A frequency domain graph of an Amplitude Modulated carrier. C. A frequency domain graph of a Phase Modulated carrier. D. A frequency domain graph of a Quadrature Amplitude Modulated carrier. E. A frequency domain graph of an FHSS Modulated carrier. F. A time domain graph of a Frequency Modulated carrier. G. A time domain graph of an Amplitude Modulated carrier. H. A time domain graph of a Phase Modulated carrier. I. A time domain graph of a Quadrature Amplitude Modulated carrier J. A time domain graph of an FHSS Modulated carrier. K. An example of multiplexing. L. None of the Above. M. All of the Above.
On the busy hour of the busiest day of the year, at a certain company, the SMDR reports to you that the average call holding time is 30 seconds, and that the call frequency is 900 calls per hour. What is the traffic volume in the ccs? Remember ccs is call seconds divided by 100. a. 900 ccs b. 90 ccs c. 9 ccs d. 40 ccs e. 50 ccs f. 27 ccs g. 270 ccs h. 55 ccs i. 45 ccs j. 15 ccs k. None of the above
G (270 ccs)
a
In Fig. 2, the domain representation of the carrier signal is best described by which labeled Item? A. Item A B. Item B C. Item C D. Item D E. All of the above. F. None of the above.
d
In Fig. 2, the domain representation of the information signal is best described by which labeled Item? A. Item A B. Item B C. Item C D. Item D E. All of the above. F. None of the above.
b
In Fig. 2, the domain representation of the upper side band is best described by which labeled Item? A. Item A B. Item B C. Item C D. Item D E. All of the above. F. None of the above.
G
rom Fig. 1, assume Signal A is the same information signal used to modulate both carrier signals, i.e. both Signal B and Signal C. In Figure 1, it would be correct to say that Signal B is (choose the best answer): A. A frequency domain graph of a Frequency Modulated carrier. B. A frequency domain graph of an Amplitude Modulated carrier. C. A frequency domain graph of a Phase Modulated carrier. D. A frequency domain graph of a Quadrature Amplitude Modulated carrier. E. A frequency domain graph of an FHSS Modulated carrier. F. A time domain graph of a Frequency Modulated carrier. G. A time domain graph of an Amplitude Modulated carrier. H. A time domain graph of a Phase Modulated carrier. I. A time domain graph of a Quadrature Amplitude Modulated carrier J. A time domain graph of an FHSS Modulated carrier. K. An example of multiplexing. L. None of the Above. M. All of the Above.
multiplexing and encapsulation
two functions supported by the osi layered model of communication are what? 34
iii. Shannons theroem 1) C = B log (base 2) 1+S/N a) B = bandwidth in hertz, cycles/sec b) 1 + s = signal power/ noise power c) C = channel capcaity d) Noise power near 0 and signal power very large, capcaity goes up Noise gets great enough, no capacity will get to that channel
what is shannons thereoem?
