DATA AND DIGITAL COMMUNICATIONS
COE 3
NAME: Philip Joshua B. Abellera
ID Number: 18-UR-0316
Year and Section: 4th YR. 3B
Activity 8
Answer the following questions and don’t forget to provide the references in APA Format. This
activity may be handwritten or encoded.
ANSWERS:
1. Types of Errors- Whenever bits flow from one point to another, they are subject to
unpredictable changes because of interference. This interference can change the shape of the
signal. The term single-bit error means that only 1 bit of a given data unit (such as a byte,
character, or packet) is changed from 1 to 0 or from 0 to 1. The term burst error means that
2 or more bits in the data unit have changed from 1 to 0 or from 0 to 1. The central concept in
detecting or correcting errors is redundancy. To be able to detect or correct errors, we need to
send some extra bits with our data. The correction of errors is more difficult than the detection.
In error detection, we are only looking to see if any error has occurred. The answer is a simple
yes or no. We are not even interested in the number of corrupted bits.
2. Similarities between the TCP/IP model and the OSI model
Both are logical models.
Both define standards for networking.
Both provide a framework for creating and implementing networking standards and
devices.
o Both divide the network communication process into layers.
o In both models, a single layer defines a particular functionality and sets standards for
that functionality only.
o Both models allow a manufacturer to make devices and network components that can
coexist and work with the devices and components made by other manufacturers.
o Both models simplify the troubleshooting process by dividing complex functions into
simpler components.
Differences between the OSI model and the TCP/IP model
o
o
o
o
o
o
o
o
o
The OSI Layer model has seven layers while the TCP/IP model has four layers.
The OSI Layer model is no longer used while the TCP/IP is still used in computer
networking.
To define the functionalities of upper layers, the OSI model uses three separate
layers (Application, Presentation, and Session) while the TCP/IP model uses a
single layer (Application).
Just like the upper layers, the OSI model uses two separate layers (Physical and
Datalink) to define the functionalities of the bottom layers while the TCP/IP uses
a single layer (Link layer) for the same.
To define the routing protocols and standards, the OSI model uses the Network
layer while the TCP/IP model uses the Internet layer.
The OSI model is well documented than the TCP/IP model.
DATA AND DIGITAL COMMUNICATIONS
COE 3
3. Encryption uses algorithms to scramble your information. It is then transmitted to the
receiving party, who can decode the message with a key. There are many types of algorithms,
which all involve different ways of scrambling and then decrypting information. Historically,
additive ciphers are called shift ciphers because the encryption algorithm can be interpreted
as “shift key characters down” and the encryption algorithm can be interpreted as “shift key
characters up.”
Decryption is a process that transforms encrypted information into its original format. The
process of encryption transforms information from its original format called plaintext into an
unreadable format called ciphertext — while it is being shared or transmitted. In addition, the
encryption and decryption algorithms are inverses of each other.
4. Viruses and worms are malicious programs that self-replicate on computers or via
computer networks without the user being aware; each subsequent copy of such malicious
programs is also able to self-replicate.
Viruses can be divided in accordance with the method used to infect a computer:
o file viruses
o boot sector viruses
o macro viruses
o script viruses
o This subclass of malicious programs includes the following behaviours:
o Email-Worm
o IM-Worm
o IRC-Worm
o Net-Worm
o P2P-Worm
o Virus
o Worm
5. Black hat hackers are the "bad guys" of the hacking scene. They go out of their way to
discover vulnerabilities in computer systems and software to exploit them for financial gain
or for more malicious purposes, such as to gain reputation, carry out corporate espionage, or
as part of a nation-state hacking campaign.
White hat hackers can be seen as the “good guys” who attempt to prevent the success of
black hat hackers through proactive hacking. They use their technical skills to break into
systems to assess and test the level of network security, also known as ethical hacking.
Grey hat hackers sit somewhere between the good and the bad guys. Unlike black hat
hackers, they attempt to violate standards and principles but without intending to do harm
or gain financially. Their actions are typically carried out for the common good.
REFERENCES:
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Forouzan, Behrouz. A. (2013). Data Communications and Networking (5th ed.)
Computer Networking Notes and Study Guide (2022). Retrieved from:
https://www.computernetworkingnotes.com/ccna-study-guide/similaritiesanddifferences- between-osi-and-tcp-ip-model.html
Karpersky.
(2022).
Viruses
and
Worms.
Retrieved
from:
https://encyclopedia.kaspersky.com/knowledge/viruses-and-worms/
Hemanth, Jude, Fernando, Xavier, Lafata, Pavel, & Baig, Zubair. (2018).
International Conference on Intelligent Data Communication Technologies and
Internet of Things (ICICI) 2018 (Vol. 26).
Fortinet.
(2022).
What
is
Hacking.
Retrieved
from:
https://www.fortinet.com/resources/cyberglossary/what-is-hacking