Network Architecture Introduction to Networks PDF

Network Architecture: Introduction to Networks Basic Concepts OSI and TCP/IP Models Yaovi SOGLO [email protected] Objectives This introduction aims to:. ✓Understand the fundamental concepts of networks ✓Identify the different types of networks (LAN, MAN, WAN, PAN). ✓Understand the role...

Network Architecture: Introduction to Networks Basic Concepts OSI and TCP/IP Models Yaovi SOGLO [email protected] Objectives This introduction aims to:. ✓Understand the fundamental concepts of networks ✓Identify the different types of networks (LAN, MAN, WAN, PAN). ✓Understand the role and functioning of the OSI and TCP/IP models. ✓Grasp the processes of data encapsulation and decapsulation. 2  Basic Concepts 3 Basic Definitions and Concepts ▪ Network: A set of interconnected computers or devices that exchange data or share resources (printers, servers, files, etc.) ▪ Protocol: A set of rules for data exchange over a network (TCP/IP, HTTP, FTP). ▪ Data communication: Transmission and reception of information between two devices. 4  ▪ 1792 - 1838: The Chappe brothers invent the optical telegraph in Historical France. 1960s: ARPANET, the first network. Context and ▪ ▪ 1980s: Development of TCP/IP and Ethernet. Evolution ▪ 2000s: Wireless networks and mobile connectivity. ▪ Today: Cloud computing, IoT, and 5G networks. 5  Types of Networks PAN (Personal Area Network) : A very small network, typically covering up to 10 meters. Used to connect devices like smartphones, tablets, or laptops. Example: Communication between a smartwatch and a smartphone. LAN (Local Area Network) : PAN Covers a small geographic area, typically a building or campus. Uses technologies like Ethernet or Wi-Fi. LANs are fast and manage local resources (printers, shared files). Example: Corporate network, home network. 6  Les Types de Réseaux MAN (Metropolitan Area Network) : Covers a city or large metropolitan area. Often used to connect multiple LANs over long distances. Example: A network of several universities interconnected within a city. WAN (Wide Area Network) : PAN Covers very large geographic areas, such as a country or multiple continents. Uses technologies like MPLS, satellites, or undersea fiber optics. Typical example: The Internet, the largest existing WAN. 7 8 Presentation of OSI Model ▪ OSI Model (Open Systems Interconnection): A reference framework that divides networking functions into 7 distinct layers. This model is used to understand how protocols and devices communicate over a network. 9  application services close to users 7 Layers of OSI encodes encrypts and model compresses useful data establishes sessions between applications establish, maintain and terminate sessions between end devices addresses interfaces globally and determines the Network best route through an inter-network addresses interfaces locally, delivers Data Link information locally, MAC method signal encoding, cables and connectors, Physical physical specifications 10 Media Layers Physical Layer: Role: Transmits bits (0s and 1s) between two devices via a physical medium (cable, fiber, radio waves). Transmitted information: Bits. Transformations: Binary data is converted into electrical, optical, or radio signals. Emission: Data is transformed into signals. Reception: Signals are converted back into binary data. Repeaters Cables, Connectors Hubs Physical 11 Media Layers Data Link Layer: Role: Provides reliable data transfer between two physically connected devices. Manages MAC addressing and error detection/correction. Transmitted information: Frames. Transformations: Adds headers with the source and destination MAC addresses. Emission: Frames are sent to the physical device. Reception: Frames are extracted from the received signals, and errors are corrected if necessary. Switch Network Card Data Link Physical Repeaters Cables, Connectors Hubs 12 Media Layers Network Layer : Role: Responsible for routing packets across the network from point A to point B using IP addresses. Transmitted information: Packets. Transformations: Adds an IP header with source and destination IP addresses. Emission: Packets are routed to the appropriate network. Reception: The packet is received and directed to the Data Link layer. Router Network Switch Network Card Data Link Repeaters Cables, Connectors Hubs Physical 13  Host Layers Transport Layer: Role: Ensures end-to-end reliable communication between hosts using mechanisms like segment management, flow control, and error correction. Transmitted information: Segments (for TCP) or datagrams (for UDP). Firewall Transformations: Adds headers to ensure data integrity Host (source/destination port numbers, sequence numbers). Emission: Segments are fragmented and sent. Reception: Segments are reassembled to reconstruct the data. 14  Host Layers Session Layer: Role: Manages sessions or connections between two hosts, allowing session establishment, maintenance, and termination. Transmitted information: Application data. Transformations: Controls dialogues between systems. Emission and Reception: Manages the opening and closing of Firewall communication sessions. Host Presentation Layer : Role: Translates data from the format used by the application to the standard format used for transmission. Also handles compression and encryption. Transformations: Data can be compressed or encrypted. Emission: Data is formatted for transmission. Reception: Data is decompressed or decrypted. 15 Host Layers Application Layer : Role: Provides network services to applications. Examples of services: HTTP, FTP, SMTP. Transmitted information: Application data. Emission and Reception: Direct interaction with software or end-users. Firewall Host 16 Encapsulation/Decapsulation When transmitted, a message undergoes transformations successively through each layer from its creation (Layer 7) to its physical transmission (Layer 1). This is called encapsulation. When this same message is received, the transformations are performed in reverse order until the message is presented to the recipient. This is called decapsulation. 17 OSI Vs TCP/IP OSI: A theoretical 7-layer model, where each layer has a specific role. TCP/IP: A more practical model with 4 layers: Application (combines OSI Layers 5, 6, and 7) Transport (equivalent to OSI Layer Internet 4) Internet (equivalent to OSI Layer 3) Network Network Access (combines OSI Layers 1 and 2) Access 18  TCP/IP model TCP/IP Model is based on two main protocols: the Transmission Control Protocol (TCP) and the Internet Protocol (IP). It is divided into four layers: Internet Network Layer: Responsible for data transmission over the network. Uses IP addresses to identify devices and routing protocols to route data between devices. Network Transport Layer: Responsible for reliability and flow Access control of data. Uses TCP and UDP to ensure proper data transmission. 19  TCP/IP model Application Layer: Responsible for communication between applications. Provides high-level services for applications such as email, file transfer, and web browsing. Physical Layer: Responsible for data transmission over the physical network. Defines the physical specifications Internet of cabling, connectors, and electrical signals used to transmit data. One advantage of the TCP/IP model is that it is simpler than Network the OSI model, making it easier to understand and Access implement. The TCP/IP model is widely used on the Internet and has become the standard layered protocol model for networks. 20 Conclusion 21  Conclusion ❑ In this first part, we covered the fundamental concepts of networks, from their history to their various typologies. ❑ We also explored the OSI and TCP/IP models, two essential pillars for understanding how data flows through a network. ❑ In conclusion, this introduction lays the groundwork necessary to understand the functioning of modern networks. ❑ The concepts discussed today will be further developed in the following chapters, where we will explore in detail the technologies and protocols that structure and secure these networks. 22 Thanks for your attention