University of Maryland University College
ITEC 626 Mid-Term Examination
1. The layer of operation and justification are identified below.
of the OSI Model
Both repeaters and hubs function as links and cable
connectors to all devices connected. Secondly, the
physical layer includes the physical and electrical
requirements for data transmission through cables.
Routers connect networks, and the OSI Model layer
that supports data processing and transmission is the
network layer. After processing, it uses routers to
transmit it from one node to another over the network.
The file transfer protocol (FTP) is an online file
transmission method, and thus, it is applicable in the
transport layer where transmission occurs in the OSI
The simple mail transfer protocol (SMTP) is an
electronic mail communication protocol. Since in the
OSI model, all the communication happens in the
application layer, then SMTP is no exception.
The presentation layer is tasked with determining the
format of data before it is offered to the application
layer for transmission. The JPG protocols ensure that
images are in the right presentation format.
As mentioned earlier, data is transmitted over the
network, and internet protocol is a data transfer
method. Therefore, it works on the network layer. It
delivers data packets through ordered addressing
The Sessions layer is designed to define how data
conversations occur and how they are controlled. It
also manages messages conversations and creates
feedback if messages bounce.
Before data is transmitted from the source to the
destination, it has to be protected from unauthorized
access. The presentation layer is tasked with the role of
encryption at the source side and decryption at the
destination. Additionally, it supports the application
layer, which is used to communicate and display the
message to the end-user.
Before packets are transmitted over the network, it has
to be ordered and reassembled, and the work of
transmission is done by the transport layer. If data is
found to be broken, the layer performs recovery for
transmission over the network connections.
Formatting of application data is done at the
presentation layer because it is the translator between
the application and network layers. The syntax of data
must be checked before transmission over the
application layer (Mitchell, 2018).
2. Standard features of Ethernet and WLAN.
Both use the IEEE 802 standards with similar reliability levels.
Both are network infrastructures used for communication and data transfer over
WLAN and Ethernet use the Carrier-Sense Multiple Access mechanisms to detect
and avoid a collision in the network.
Differences between Ethernet and WLAN
It is based on the IEEE standards family
They operate on the family 802.11 of IEEE.
Uses electric signals for physical connection.
Utilizes high energy radiofrequency; thus, no
physical connection is needed.
The network uses a full-duplex mechanism
The networks use a half-duplex mechanism
The networks use CSMA/CD to detect
They use CSMA/CA to avert network
3. a. Frequency Modulation – refers to the method of encoding data or information in a wave
carrier for transmission through changing the frequency of the wave instantaneously.
Advantages of Frequency Modulation (FM)
Resilient to noise – audio output is not affected during transmission.
It is possible to apply low power to the transmitter – there is no need to
increase the power during transmission.
One can use RF amplifiers in the market.
Disadvantages of Frequency Modulation (FM)
o Poor spectral efficiency for different formats.
o It uses a complex demodulator.
3. b. Amplitude Modulation – it is described as a modulation method where the signal strength of
the carrier wave is varied in proportion to the transmitted message signal.
Advantages of using the Amplitude Modulation (AM)
❖ Easy to implement.
❖ Cheap signal receivers
Disadvantages of using the Amplitude Modulation (AM)
❖ Inefficient use of power.
❖ Poor bandwidth usage.
❖ Susceptible to high noise levels.
3. c. Phase Modulation – is viewed as the process of varying the phase of the carrier wave
through vibrations of the source of the sound while keeping the frequency of the wave carrier
Advantages of using the Phase Modulation (PM)
➢ It is simple
➢ High immunity against noise
➢ It permits high-speed communication between computers using a
Disadvantages of using the Phase Modulation
➢ Modulation requires two signals by space variation between waves.
➢ The method requires complex hardware.
➢ There is phase ambiguity.
3. d. Pulse Modulation – it refers to the procedure of converting the wave carrier into a series of
spaced pulses with a constant amplitude.
Advantages of using the Pulse Modulation
Efficient data transmission.
It is easy to separate the noise from the signal.
Constant power output.
Requires less power
Less noise interference as the amplitude is held constant.
Disadvantages of using the Pulse Modulation
Requires large bandwidth.
It has a complicated implementation procedure.
It is profoundly affected by multi-pathway interference.
Both devices have to be synchronized (Hub, 2015).
The telephone networks have evolved from a circuit-switched network to a packetswitched system due to societal needs, increased user numbers, technological
advancements, and communications. Additionally, the evolvement is due to the need
for greater efficiency and lowered costs. Circuit-switched networks were designed
for voice communications and are used by the Public Switched Telephone Network
(PSTN). The circuit switching connection is physically orientated and provides a
dedicated, physical contact between the message source and receiver from the time
connection is initiated to when it ends. It is implemented at the Physical layer, and a
dedicated channel must be re-established. The data (voice) is then transferred through
a predetermined path/order and utilizes the full bandwidth of the significant line.
While circuit-switched networks increase reliability, it can also cause delays due to
the unavailability of channels and higher costs associated with dedicate connections
and strained bandwidth.
Packet-switched networks are more efficient for data, and they do not require a preestablished connection, increasing the availability of bandwidth, respect, and
channels. In packet switching, data is divided into packets that are assigned a source
and destination address. These packets route themselves to their destination using the
most efficient route based on circuit availability and then reassembles the original
data. Packet switching occurs at the Network layer and can use a datagram or virtual
circuit approach to determine how the packets will arrive at the destination.
5. TCP stands for Transmission Control Protocol, and UDP stands for User Datagram
Protocol. Both are transportation protocols, and they operate in the transport layer.
They are commonly used for sending packets over the Internet. The contrast between
the two contracts is as shown below.
The contrast of TCP and UDP
Slow and reliable
1 It is fast and unreliable
It is a connection-oriented protocol
TCP is stream-oriented, preserves order,
and manages flow in data transmission.
Use numbered packets to check errors
and to track communication.
2 It is a connectionless protocol
3 UDP does not manage data
flow in transmission.
4 UDP has no mechanisms to
trace packet transmission.
Live video stream – use the UDP Protocol.
Email – use the TCP Protocol.
Satellite pictures – utilize the UDP.
Tax data – employ the TCP protocol.
Online gaming – the suitable protocol is UDP.
6. a. The Domain Name System (DNS) is a critical network protocol that converts
hierarchical text names that are human-friendly, to IP addresses. It is distributed,
maintaining its servers to translate titles and store DNS cache. DNS eliminates the need
for users to remember actual IP addresses and functions similar to a phonebook of the
Internet, and is crucial, as it serves as a digital identity. Therefore, security issues that
create DNS risks must be mitigated, especially with malware and cyber threats increase.
Some significant risks include registrar hijacking and cache poisoning. Registrar
hijacking occurs when hackers take control of the domain by hacking passwords or
registrars. Hackers can also use cache poisoning, by redirecting users through fraudulent
addresses in the DNS servers where DNS data is cached.
6. b. Dynamic Host Configuration Protocol (DHCP) is the mechanism by which hosts are
assigned IP addresses. Security is essential to protect the DHCP server from unauthorized
access to IP addresses. Not protecting access points or the network can lead to security
risks to the DHCP server can result in denial-of-service attacks, in which access to
legitimate IP addresses are denied due to all available IP addresses being used up (Rouse,
6. c. Internet Control Message Protocol (ICMP) is an error reporting protocol that
network devices use to generate and communicate error messages when IP packets
cannot be delivered due to network problems (Rouse, 2015). Security issues of the ICMP
can result in numerous risks including ICMP tunneling, in which covert channels that are
not controlled by security mechanisms are formed between the client and server using
echo requests and reply packets; and Smurf attacks in which source addresses of ICMP
packets are spoofed, and broadcast is sent to all computers to congest the network.
7. Extensible Markup Language (XML) and Simple Object Access Protocol (SOAP) enable
applications developed through different programming languages to exchange
information and reduce interoperability issues. Extensible Markup Language (XML) is a
markup language that is self-descriptive and designed to store and transport data over the
Internet. It contains sender and receiver information, a header, and a message in the body.
Web applications use XML to tag the data, and SOAP is used to transfer the message.
SOA is a messaging protocol used to send and receive XML-based messages between
8. Relational Database (RDB) and Object Database (ODB) systems both store data in an
organized structure but uses varying approaches to do so. RDB stores data and the
relationship between the data in tabular form, which consists of rows that contain primary
keys and columns with unique names. Data in RDB is represented by files, records, and
fields, and further stores relationships between the data within the columns. It is simple
and can only store the data. OBD stores data as objects and is capable of storing a variety
of data types, as well as methods that can be reused and provide faster access. It is also
able to store unstructured data efficiently.
9. Big data provides opportunities for businesses to better their decision-making processes
and operations to develop better strategies to meet their objectives and goals. Big data are
large data sets that include both structured and unstructured data that can be mined for
insight. Similarly, big data can contribute to network management operations. Information
that is collected from various points across the network can be used to optimize network
operations. Big data can help to map correlations between network problems and typical
timelines of events, helping to pinpoint network related issues. It also helps in root cause
analysis, enabling identification of network problems that impact the system, and then
tracing the data back to the source or related events. Another benefit is that big data can
help establish a baseline for normal network conditions, which helps to alert when
situations arise that are abnormal and needs attention.
10. Service-Oriented Architecture (SOA) and cloud computing both offer scalability and
agility, and interoperability, with reduced costs. However, SOA is more an application
architecture providing horizontal services, as opposed to cloud computing, which aligns
with an IT architecture with vertical services. SOA is an architectural approach that
organizes system components based on the service it provides and provides a collection of
services according to business functionality. SOA services are well-defined, selfcontained, functional, and reusable. It uses loose coupling, allowing services to operate
independently from the platform and enabling businesses to extend or upgrade existing
facilities. The benefits of SOA include improved interoperability, flexibility, and
reliability. It also decreases the costs associated with software development and
management expenses. Another great benefit of SOA is that it reduces the time to market
by enabling quicker development, with improved performance and functionality.
In cloud computing, virtualized software, infrastructure, and platforms are provisioned by
the cloud service provider through the Internet. This allows businesses to access unlimited
resources that are scalable based on needs and changing demands. It provides greater
accessibility and interoperability while reducing hardware and maintenance costs.
However, the quality of service and security is dependent on the capabilities of the service
provider, and businesses must rely on the service provider’s ability to safeguard and secure
Mitchell, B. (2018). The layers of the OSI model illustrated. Life Wire. Retrieved from
Electronics Hub. (2015). Modulation and different types of modulation. Retrieved from
Rouse, M. (2015). ICMP (Internet Control Message Protocol). Tech Target. Retrieved from
PMAN635- Spring 2020
Session 7 - PMAN635 Mid-Term Exam
Name: (Your name goes here)
Please answer any ten of the twelve questions. Each question is weighted equally. If you answer
more than ten questions, I will select the best ten. Note that the highest grade you can receive is
In addition to posting this answer sheet, be sure to post an excel file that shows your calculations.
If you chose a problem that requires CB, you must post the file that includes your assumptions,
forecast and the results of your simulations. Post any MS Project file you used to answer a
question. DO NOT just insert MS Project, Excel or CB derived answers in your answer sheet.
1. Two investments (A and B, below) have been proposed to the Capital Investment committee
of your organization;
a. The required rate of return for your company is 15%. What is the NPV for each
investment? Assume the initial investments ($150k and $50k) occur at the
beginning of the year and all other costs and benefits occur at the end of the year
indicated. Ignore inflation.
b. What is the payback period for each investment?
c. Which investment would you recommend and why?
d. Why might you recommend the other investment?
2. Using the forward and backward pass method, identify the Critical Path and total duration for
the following network. Show all work.
PMAN635- Spring 2020
3. For the network below:
a. Calculate T-E and Variance for each activity. Assume the durations have 95%
certainty (i.e. the range from optimistic to pessimistic durations covers 95% of all
b. Calculate the expected duration of the network. Do not use Crystal Ball.
c. What is the probability the network will take no more than 23 days? Use the Ztable or Excel’s NORM.DIST formula, not Crystal Ball. Be sure to show all
4. You are still trying to get your engineering cost estimate for the Kuraiz-Reconda Fiber Optic Cable
(KRFOC) project approved by your sponsor (remember IA-5?). In opening your morning mail,
however, you see a proposal from Engineers ‘R Us to do all the KRFOC engineering for a fixed price
of $60,000. Comparing that with your estimate of doing the work yourself (See the IA-5 question 2b
a. What is the probability that the price for completing the work yourself will be less than
the Engineers ‘R Us offer? Show all work.
b. Would you recommend the work be done in-house or accept the fixed price offer from
Engineers ‘R Us? Why or why not?
Be sure to provide all calculations.
5. Which of the following are activities and which are work packages?
Prepare the purchase order for a router
System Design Package
Install the foundation
6. Please answer each of the following:
a. What is the expected time to complete a task with an optimistic (a), most likely
(m), and pessimistic (b) times of 2, 4 and 7 days respectively?
b. What is the standard deviation of the same task, assuming that 99.7% of the
outcomes fall between a and b?
c. What is the standard deviation of the same task, assuming that 90% of the
outcomes fall between a and b?
PMAN635- Spring 2020
7. There are three (and only three) paths through a network (project), each with a probability of
completion in less than 24 months as indicated:
• S- a-b-F P1(<24) = .80
• S- d-e-F P2(<24) = .80
• S- g-h-F P3(<24) = .80
d. If the tasks are independent, what is the probability of the project being completed
within 24 months? Note: S is the start node, F is the finish node
e. What is the probability the project being completed in 24 months or longer?
8. Match each of the following activities with one of the five project management process
groups (initiating; planning; execution; monitoring and control; closing).
f. You are preparing the monthly project status report.
g. You are completing formal transfer of the product developed by your project team
to the customer.
h. Your project sponsor is reviewing the list you prepared of the functional managers
and other stakeholders who might be affected by your project. Once approved,
you will publish this as a part of your stakeholder management plan.
i. The installation team is completing all as-built drawings.
9. Which of the following statements are true and which are false:
j. A discrete activity is one which does not provide a definitive end product and is
measured by the passage of time.
k. To account for the risk of predicting future profits, you would decrease the
relative variance for those profits the further from your baseline year that they are.
l. An activity’s float is the amount of time its start time or duration can be extended
without affecting the start of the next task.
m. Slack is a term coined by Professor Hall to indicate that a student ought to wake
up and get this exam posted!
10. Answer one of the two following questions:
n. Name one thing you have learned so far this semester and how you might apply it
if assigned to a project in your organization.
o. You ...
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