Comprehensive Analysis of ITSM, SDLC, OSI Protocol, and TCP/IP Models

This report provides a comprehensive analysis of IT Service Management (ITSM) and Software Development Life Cycle (SDLC) methodologies. It begins by comparing the OSI protocol stack and TCP/IP, highlighting their advantages and disadvantages, and includes calculations to determine the estimated overhead percentages for TCP/IP protocols in IPv4 and IPv6 transmissions. The report then delves into ITSM, outlining the roles and responsibilities of incident and change managers within an IT environment. Furthermore, the report examines and contrasts various SDLC models, including Waterfall, V-shaped, and Spiral models, evaluating their strengths and weaknesses, and explaining their suitability for different project types. The document concludes by summarizing the key aspects of each model, providing a clear understanding of their applications in software development.

Running head: ITSM AND SDLC
ITSM and SDLC
Name of the Student
Name of the University
Author Note:

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ITSM AND SDLC
Table of Contents
Question 1........................................................................................................................................2
Question 2........................................................................................................................................4
References........................................................................................................................................8

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Question 1
OSI Protocol Stack and TCP/ IP
The OSI protocol stack involves presentation and session layers apart from the
application layer. However, the applications of TCP/ IP like FTP and Telnet do not comprise of
any separate layer. The TCP/IP application layer is the combination of three layers, which are
session, presentation and application. It is not required to separate these layers as TCP/ IP
applications do not possess any sort of clear differentiating points within protocols, interfaces
and services (Edwards & Bramante, 2015). Moreover, a layer of the model is both
connectionless and oriented with connection. As a result, it is not needed to distinguish session
and presentation layers separately.
The main advantages of incorporation of the OSI approach into TCP/IP are as follows:
i) It would become a generic model and would also act as the basic guidance tool for
proper development of any networking model.
ii) It would support both connectionless and connection oriented services as a result,
different layers are not required.
The main disadvantages of incorporation of the approach of OSI into TCP/IP are as
follows:
i) There would be an issue with the launching time, since OSI is basically a theoretical
model and does not always have considerations for the availability of proper technology (Alani,
2014).
ii) Moreover, the expense would be higher as the model would become highly complex.

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Calculations for Finding out the Estimated Percentages of Overhead for TCP/ IP Protocol for
IPv4 and IPv6 versions
Solution:
For Ethernet MTU (Maximum Transmission Unit) configured at 1500 Bytes, the maximum
segment size can be calculated by subtracting the entire size of headers from the MTU.
TCP has size of 160 bits which is equal to the 20 Bytes
In IPv4 transmission,
The IPv4 header has the size of 160 bits that is equal to the 20 Bytes.
Hence the entire size of the headers (overhead) = TCP header + IPv4 header = 20 Bytes+ 20
Bytes = 40 Bytes.
=> Payload = MTU size – headers size
=> Payload = 1500 – 40 = 1460 Bytes.
Now overhead percentage is calculated with the formula of,
Overhead (%) = overhead
Payload ∗100
Overhead (%) = 40
1460∗100
Overhead (%) = 2.739% Ans.
In case of IPv6 transmission,

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The IPv6 header has the size of 320 bits that is equal to the 40 Bytes.
Hence the entire size of the headers (overhead) = TCP header + IPv6 header = 20 Bytes+ 40
Bytes = 60 Bytes.
=> Payload = MTU size – headers size
=> Payload = 1500 – 60 = 1440 Bytes.
Now overhead percentage is calculated with the formula of,
Overhead (%) = overhead
Payload ∗100
Overhead (%) = 60
1440∗100
Overhead (%) = 4.166% Ans.
Question 2
Response to part 1:
ITSM is referred to as IT service management that indicates towards the entire activities
which are in turn structured and organized in both supporting processes and procedures and are
directed by various types of policies (Marrone et al. 2014). These particular procedures are
performed by any organization for planning, designing, delivering, operating and controlling of
the information technology services which are offered to the customers.
Several kinds of new and advanced technologies and tends of ITSM which are surfacing
nowadays comprises of artificial intelligence, automation and business relationship management,
customer experience, chat bots, cloud, agile to name a few. Several kinds of advantages are

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associated with artificial intelligence are frequent breaks are not required by the machines like
that of the human beings as the machines are developed to be intelligent like human beings. On
the other hand, business relationship management helps in articulating the needs of the business
in a much better manner.
Response to part 2:
Various responsibilities and roles of the incident manager comprises of managing of
several kinds of processes for the aim of restoring various kinds of operations related with the
service in a normal manner. These kinds of tasks are performed by the incident manager very
quickly for the aim of minimization of various types of impacts to the operations of the business
(Palilingan & Batmetan, 2018). Incident manager is accountable for both planning as well as
coordinating the entire activities which are required for performing, monitoring along with
reporting on all the processes.
This manager is accountable for remediation of the deviation of any single process with
respect to its department/division. This manager is accountable for the occurrence of
communication with the owner of all the incident procedures. This manager forms one of the
important contact point for all sorts of major incidents. This manager is also responsible for
implementing several types of processes of incident management in an effective manner and
focuses on carrying out of the respective procedures related with that of reporting. All the
escalations of the first stage with respect to the incidents are represented by this manager.
The responsibilities and roles of a change manager in ITSM manager comprises of the
authorization as well as approval of the changes which are minor or low in nature (Pollack &
Algeo, 2014). The change manager is accountable for holding along with coordinating meetings

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with the CAB or the Change advisory board for the aim of the discussion of the changes of the
higher level of risks. The change advisory board is frequently referred to as a bunch of
individuals who act in the form of an advisory committee for certain changes which are to be
significant or major in nature.
It becomes the responsibility of the change manager in ensuring that each and every
activity which are designed for the aim of implementation of the changes are done with respect
to that of the standards. In addition to this, the accountability of change manager also lies in the
entire implementation of the changes or the rejection of any specific change. The summary sheet
of change is in turn prepared by the change manager which helps in summarizing all RFCs. This
particular sheet helps the team of CAB in understanding as well as evaluating the change which
has been proposed.
Response to part 3:
Spiral model became successful in overcoming the V-shaped cycle model and Waterfall
cycle model as the avoidance of the risks could be enhanced by the utilization of the spiral
model. In addition to this, the spiral model forms the right choice for the larger projects which
are mission-critical in nature (Boehm et al., 2014). Some of the best qualities which are
possessed by this particular model is that it has a strong approval along with control in the part of
documentation.
On the other hand, several kinds of new and advanced function could also be added at the
later stage in this model and lastly the best part of the spiral model indicates that any software
gets produced very early in the life cycle of the software. The addition of the new and advanced
function were just not possible along with higher levels of risk in the waterfall model which is

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possible in the spiral model. Spiral model is comparatively flexible than the V-model and
requires to be updated at every stage.
Response to part 4:
Waterfall SDLC model:
The waterfall model of SDLC forms the first SDLC approach that was utilized for the
development of the software. This particular waterfall model helps in the illustration of the
development procedures of a software in a linear sequential manner (Model, 2015). This
indicates that any phase in the processes of development commences only after its respective
previous phase gets completed.
V-shaped SDLC model:
V-model is a kind of model of SDLC where several types of processes gets carried out in
a sequential procedure just in the shape of a V. It is often indicated as the Verification and
Validation model and bases on the association of a single testing phase with respect to every
single stage of development (Despa, 2014). Development of each of the steps is directly linked
with that of the phase of testing.
The scenario where the V-models gets best suited is the small projects where the
requirements of that particular project is very clear like the issue which are overlooked
possessing some of the basic system design, The scenario where the waterfall model of SDLC
gets best suited was the applications of the development enterprise like that of human resource
management system and customer relationship management system to name a few.

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References
Alani, M. M. (2014). Guide to OSI and TCP/IP models.
Allen, D. K., Karanasios, S., & Norman, A. (2014). Information sharing and interoperability: the
case of major incident management. European Journal of Information Systems, 23(4),
418-432.
Boehm, B., Lane, J. A., Koolmanojwong, S., & Turner, R. (2014). The incremental commitment
spiral model: Principles and practices for successful systems and software. Addison-
Wesley Professional.
Despa, M.L., 2014. Comparative study on software development methodologies. Database
Systems Journal, 5(3), pp.37-56.
Edwards, J., & Bramante, R. (2015). Networking self-teaching guide: OSI, TCP/IP, LANs,
MANs, WANs, implementation, management, and maintenance. John Wiley & Sons.
Marrone, M., Gacenga, F., Cater-Steel, A., & Kolbe, L. (2014). IT service management: A cross-
national study of ITIL adoption. Communications of the association for information
systems, 34(1), 49.
Model, W. (2015). Waterfall model. Luettavissa: http://www. waterfall-model. com/. Luettu, 3.
organisational change project activities and stages. Journal of Modern Project
Management, 2(2), 8-17.

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Palilingan, V. R., & Batmetan, J. R. (2018, February). Incident management in academic
information system using ITIL framework. In IOP Conference Series: Materials Science
and Engineering (Vol. 306, No. 1, p. 012110). IOP Publishing.
Pollack, J., & Algeo, C. (2014). A comparison of Project Manager and Change Manager
involvement in organisational change project activities and stages. Journal of Modern
Project Management, 2(2), 8-17.