Networking and Software Design Patterns

This document discusses various topics related to networking, including the OSI model, TCP/IP suite, data encapsulation, network layer vs. transport layer, and the aims of the data link layer. It also covers software design patterns and their importance in software development.

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By (Student Name)
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NETWORKING
Question one
Figure 1 below shows the OSI model layer while figure 2 shows the TCP/IP suite
Open System Interconnection model
Transfer Control Protocol/Internet Protocol Suite

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Question two
To start with, the Transfer Control Protocol /IP protocol was developed before the Open
System Interconnection model. This means that the TCP/IP protocol suite doesn’t match exactly
as the Open System Interconnection model. The initial or the original Transfer Control
Protocol /Internet Protocol suite was first defined using only four layers which were the
application, host-to-host network, transport, and the internet. Nevertheless, network engineers
have put it that TCP/IP cab be compared to OSI model as host-to-host network layer is the same
as the combination of data link and the physical layers. In addition the internet layer is equivalent
to the application and network layers. The transport and the application layers carries the same
functions as the session, presentation and the application layers of the OSI model.
Hence;
TCP/IP contains five layers; 1st four layers provides internetworking, transport functions,
physical standards, and network interfaces. The 1st three layers of the OSI model are represented
by Application layer of TCP/IP (Black, 2013, p. 47).
Question 3
Network layer- Internet layer
User support – Application layer
Question 4: Data encapsulation
In respect to question to three, data encapsulation is said to be the process of taking data
from one protocol to another and then translating which is the translated into another protocol, so
that that the data can continue across the organization network

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Question 5: The aims of the data link layer
The data link is the layer two of the OSI model and it is used to define the operations
package. It is also used to unpack the data in frames
Question 6: Network layer vs. Transport layer
The network layer is used handle packet switching through the switching functions and
the logical addressing. On the other hand the transport layer is used to provide Quality of Service
functions. It is also used to complete the delivery of data. In addition, data integrity is guaranteed
at this layer through error detection.
Question 7: If data link can detect errors between hops, then what is the need of another
mechanism at the transport layer?
This is because the data link is said to have 2 routers to link directly through a physical
channel. On the other hand the transport layer is just a physical channel which is easily replaced
by the entire organization subnet. In addition, data link layer or layer two it is not necessary for
the router to specify the type of router that it wants to since each outgoing line is uniquely
specified in a panicular router.
Question 8: Duties of network layer
 Handling packet routing through switching and logical addressing
 Determining the route which is suitable of a certain packet from the source to
destination
 Determining the IP address or the logical address
 Encapsulating data
Question 9: Responsibilities of the transport
Some of the responsibilities of the transport layer are;

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 Error recovery: Transport layer is used to resend the data segments which had an error
 Flow control congestion avoidance: This is used t0o ensure that amount of information or
data sending to the destination is affordable
 Ensures a complete data transfer
 Creates end-end connection between hosts in different networks
 Congestion avoidance: With the help of DCCP, transport layer helps in preventing
congestion in this layer. This done by removing the possibilities of bottleneck issues.
Some of the major protocols in this area are DCCP, SCTP, UDP, and TC
Question 10: The difference between physical address, logical address, and the port address
The address of the network interface card is also referred to as the physical address or
what network administrators refer to as the MAC address. This is address is specifically used at
the data link layer. On the hand the logical address is the IP address of the system. It is the
combination of Host OD and Net ID. There a lot of applications which run on the computer; port
address is the address of each application on the computer. Port address is decided by the Kernal
of the OS
Question 11: Services on the application layer services
Some of the services on the application layer include
 File transfer
 Remote access
 Mail services
 Shared database management

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Question 12
It helps in combining the physical network functions such as modulation, bit
synchronization, and line coding. It also helps in error detection and frame synchronization. It
also helps in the combination of the network protocols such as the ARP, NDP, IEEE 802.11, and
IEEE 802.3 (Knapp, 2013, p. 46)
OBJECT ORIENTED SOFTWARE DEVELOPMENT
Question 1
The software design patterns are used to represent the very best practices which are
adapted by experienced OO software developers. According to software engineers, a design
patterns systematically names and explain the general design which addresses a recurring design
issue in OO.
Design was first described by Gamma where the major goal of design pattern was to
communicate the architecture and design ideas. In addition, a design pattern was there to create a
process for reliable identification of instances of the design patterns in the source code.
Examples of software design patterns as described by Smith and others are factory method; this
design pattern is used to create an object from a set of the same classed which have to be based
on some parameter. Another Design pattern is the abstract factory where the design affects the
whole bunch of classes. An example is in Java where the swing Look-and-feel. Another design
pattern is the singleton design which its main aim is to guarantee the only instance of a certain
object. Other design patterns are iterator which allows one to go through a list of objects starting
from the beginning. Then there is the template method, the command design, the observer
pattern, and the composite design pattern (Freedman, 2015, p. 79).

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A software development company can enhance productivity by implementing the patterns
which are in practice by providing proven and tested development paradigm. It is also important
to note that an effective design requires one to consider issues which may not become visible
until a later implementation. Second a software development company can achieve productivity
by combining the various design patterns into categories which are creational patterns which
include the factory method, builder, lazy initialization, object pool, prototype, singleton, and
resource acquisition is initialization. Other categories are the structural patterns which combines
the composite, decorator, and bridge. Then there is the behavioral patterns which are the
blackboard, mediator, memento, and chain responsibility.
Question 2
Design problem 1
A UML diagram is a modern approach to documenting and modelling software. It is a
diagrammatic representation of the software components. Mainly a UML diagram is used as a
general purpose for modelling language specifically in the field of software engineering. It is
used to document the workflows or processes. Example, an activity diagram which is one type of
UML diagram is used as a replacement for flowcharts. UML diagrams are specifically divided
into two which are the activity diagram, use case diagram, timing diagram, sequence diagram,
and state machine diagram. Then the structural UML diagram which are the component diagram,
composite structure diagram, object diagram, profile diagram, class diagram, and package
diagram (Beydeda, et al., 2005, p. 80).

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Fig 1: Computer price use case
Design problem 2
Note that from figure tow the checkout case has included the make purchase, and customer
register on the online system

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Fig. 2: Checkout Use case

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References
Beydeda, S., Book, M. & Gruhn, V., 2005. Software development. 3rd ed. Chicago: Springer
Press.
Black, U. D., 2013. OSI model Communication standard. 1st ed. New York: Prentice Hall Press.
Freedman, J., 2015. Software Development. 1st ed. New York: Cavendish Square Press.
Knapp, a., 2013. Nortel Networks: The complete conference. 4th ed. New York: McGraw Hill
Press.
Layton, A. I., 2009. OSI model. 3rd ed. New York: Charlotte Press.