From cb4c6ff564e913ea7eefdc270fe58fc5e036354c Mon Sep 17 00:00:00 2001 From: malmert Date: Sun, 12 Apr 2026 17:25:45 +0200 Subject: [PATCH] OSI chapter --- documentation/thesis/00-acronyms.tex | 3 +- documentation/thesis/02-preliminaries.tex | 45 +++++++++++++++++++++++ documentation/thesis/main.tex | 4 +- 3 files changed, 50 insertions(+), 2 deletions(-) create mode 100644 documentation/thesis/02-preliminaries.tex diff --git a/documentation/thesis/00-acronyms.tex b/documentation/thesis/00-acronyms.tex index 45ee240..08e5f13 100644 --- a/documentation/thesis/00-acronyms.tex +++ b/documentation/thesis/00-acronyms.tex @@ -8,11 +8,12 @@ \acro{HTTP}{Hypertext Transfer Protocol} \acro{IP}{Internet Protocol} \acro{MAC}{Media Access Control} + \acro{OSI}{Open Systems Interconnection} \acro{SSID}{Service Set Identifier} \acro{SSL}{Secure Sockets Layer} \acro{TCP}{Transmission Control Protocol} \acro{TLS}{Transport Layer Security} - \acro{UDP}{User Data Protocol} + \acro{UDP}{User Datagram Protocol} \acro{URI}{Uniform Resource Identifier} \acro{URL}{Uniform Resource Locator} \end{acronym} diff --git a/documentation/thesis/02-preliminaries.tex b/documentation/thesis/02-preliminaries.tex new file mode 100644 index 0000000..39fe296 --- /dev/null +++ b/documentation/thesis/02-preliminaries.tex @@ -0,0 +1,45 @@ +\chapter{Preliminaries} +\label{chap:preliminaries} + +In this chapter, the necessary background and foundational concepts underlying the research presented in this thesis are introduced. First, the theoretical frameworks and methodologies guiding the approach are discussed, followed by an overview of the key technologies and tools used in this work. The chapter is intended to establish a common understanding and provide context for the subsequent chapters, in which the specific contributions and findings of the research are presented. + +\section{\ac{OSI} Model} +\label{sec:osi} + +The \ac{OSI} Basic Reference Model, defined in X.200, provides a conceptual framework for understanding and standardizing communication between open systems. Its central purpose is to describe network communication in a structured and interoperable way by dividing the communication process into seven layers, each with a distinct function and relationship to the adjacent layers. This layered approach makes it possible to separate communication tasks into manageable parts, thereby supporting the design, specification, and implementation of interoperable systems. + +The \ac{OSI} model is not a concrete protocol suite but a reference architecture. In other words, it does not prescribe a specific technology for network communication; instead, it establishes a common conceptual model that can be used to describe how communication functions should be organized. The seven-layer structure is one of its most important features, because it defines a hierarchy of services and interfaces that together form a complete communication system. Each layer performs a defined set of functions and provides services to the layer above while relying on the services of the layer below. + +\subsection{Physical Layer} + +The Physical Layer is the lowest layer of the \ac{OSI} model and is concerned with the transmission of raw bit streams over a physical medium. It defines the electrical, mechanical, procedural, and functional characteristics of the physical connection. In practical terms, this layer deals with how bits are represented as signals and how they are transmitted across cables, optical fibers, or wireless links. It therefore forms the foundation of all higher-level communication, since no data can be exchanged without a functioning physical transmission path. + +\subsection{Data Link Layer} + +The Data Link Layer provides reliable transfer of data over a direct physical connection between two adjacent nodes. Its role is to organize raw bits from the Physical Layer into structured units and to support local communication across a single link. This layer is also responsible for controlling access to the transmission medium and for detecting and correcting errors that may occur during local transmission. By doing so, it helps ensure that data can be transferred efficiently and with a defined degree of reliability between neighboring systems. + +\subsection{Network Layer} + +The Network Layer extends communication beyond a single local link by providing routing and path selection across multiple interconnected networks. It is responsible for addressing and delivering data from a source to a destination that may be separated by several intermediate systems. This layer therefore introduces the concept of logical network-wide communication, which is essential for interconnection across larger infrastructures. In the \ac{OSI} architecture, the Network Layer plays a central role in enabling internetwork communication by determining how information should travel through the network. + +\subsection{Transport Layer} + +The Transport Layer provides end-to-end communication services between application entities in different systems. Its purpose is to support the transfer of data across the complete communication path, independent of the underlying network structure. This layer may provide functions such as segmentation, reassembly, flow control, and error recovery, depending on the service required. It ensures that data can be delivered between hosts in a way that is suitable for the needs of the communicating applications. + +\subsection{Session Layer} + +The Session Layer is responsible for managing communication sessions between application processes. It establishes, maintains, and terminates sessions, allowing two systems to organize their dialogue in a coordinated manner. This includes controlling the interaction between applications and supporting synchronization during communication. The session concept is important because many communication tasks require a structured exchange rather than isolated data transfers. + +\subsection{Presentation Layer} + +The Presentation Layer provides services related to the representation of data. Its function is to ensure that information sent by one system can be interpreted correctly by another system, even when the two systems use different internal data formats. This layer may therefore handle data translation, formatting, and representation issues. By separating presentation concerns from application logic, the \ac{OSI} model allows the communication process to remain flexible and independent of specific machine representations. + +\subsection{Application Layer} + +The Application Layer is the highest layer of the \ac{OSI} model and provides services directly to user-oriented application processes. It represents the point at which network communication becomes visible to the software used by the end user. This layer supports communication functions that are needed by applications and forms the interface between the communication system and the application domain. In the \ac{OSI} framework, it completes the layered communication path by enabling services that are directly relevant to user interaction. + +\subsection{Layered Structure and Function} + +A key principle of the \ac{OSI} Basic Reference Model is that each layer has a specific scope of responsibility and interacts primarily with the layers immediately above and below it. This design reduces complexity by distributing communication tasks across separate functional levels. It also promotes standardization, because each layer can be specified and analyzed independently within the overall architecture. As a result, the model provides a clear conceptual basis for understanding how communication systems are structured and how interoperability can be achieved. + +The significance of the \ac{OSI} model lies in its ability to describe communication in a modular and systematic way. Rather than treating network communication as a single undivided process, the model breaks it into coordinated functions that are easier to define, implement, and study. This makes the \ac{OSI} Basic Reference Model particularly valuable in technical writing, education, and system analysis. Even where modern protocols do not follow the model exactly, the \ac{OSI} structure remains an important reference for explaining communication principles. diff --git a/documentation/thesis/main.tex b/documentation/thesis/main.tex index 130fa81..270128c 100644 --- a/documentation/thesis/main.tex +++ b/documentation/thesis/main.tex @@ -18,7 +18,7 @@ %----------------------------------------------------------------------- \newcommand{\thetitle} -{An Investigation of the Security of Smart Doorbells} +{Design and Implementation of a Web-Based Platform for MITM Traffic Capture, Correlation, and Analysis} \newcommand{\theauthor}{Marcus Jan Almert} \title{\thetitle} @@ -73,6 +73,8 @@ \include{00-acronyms} +\include{02-preliminaries} + %\listoftables %\listoffigures %\lstlistoflistings