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1. CSE 5231 - Dr. Aydeger - Intro

Introduction to Computer Networks

  • Instructor: Dr. Abdullah Aydeger

  • Course Code: CSE 5231

  • Location: L3Harris Center for Science and Engineering #326

  • Email: aaydeger@fit.edu

  • Affiliation: Department of Electrical Engineering and Computer Science

Course Outline

  • Introduction to Computer Networks

  • Network Protocol

  • Layers

Computer Networks

  • Definition: A computer network connects two or more computing devices.

    • Examples of Devices: Computers, phones, IoT devices.

    • Terminology: Each device is referred to as a "node" and the connection between them is called a "link."

Applications of Computer Networks

  • The Internet is a well-known computer network, accessed through various applications:

    • World Wide Web (WWW)

    • Email

    • Streaming (Audio/Video)

    • File Sharing

    • Instant Messaging

Device Connections

  • Types of Links:

    • Point-to-Point Link: Direct connection between two nodes.

    • Multiple Access Link: A shared connection allowing several devices to communicate.

Networks by Scale

  • Internetwork: A larger network composed of smaller networks.

  • The Internet: Comprises all interconnected networks globally.

Protocols

  • Definition: A communication protocol is a set of rules that enables two or more entities to communicate over a network.

    • Components of Protocols:

      • Rules

      • Syntax

      • Semantics

      • Synchronization

      • Error recovery methods

Communication Protocols

  • Responsibilities of Protocols:

    • Message format

    • Message order

    • Action guidelines

  • Operates on multiple nodes and utilizes packet headers for functionality.

Designing Network Protocols

  • Challenges include managing billions of devices, ensuring communication and maintenance.

  • Solution: Divide functionality and responsibilities among protocols and networks.

Layering Concept

  • Layering abstracts and organizes network functionalities without detailing implementations.

    • Benefits of Layering:

      • Facilitates system maintenance

      • Enhances scalability

    • Protocol Stack: Layers handle specific tasks within network communication.

OSI Model

  • Overview: Utilizes a layered architecture to manage network communications:

    • Each layer has specific functionalities and builds upon lower layers.

OSI Architecture

  • Functionality: Each layer communicates with the layers above and below it and exchanges messages with peer layers across nodes.

OSI Layers Breakdown

  • Physical Layer: Manages raw bits transmission over links.

  • Data Link Layer: Collects bits into frames for transmission.

  • Network Layer: Responsible for routing within packet-switched networks.

  • Transport Layer: Ensures data transfer from end-user to end-user.

  • Session Layer: Manages sessions communicating multiple transport streams.

  • Presentation Layer: Addresses data format issues between communicating peers.

  • Application Layer: Standardizes common exchanges for user applications.

TCP/IP Layers

  • Application Layer: Deals with user-facing applications.

  • Transport Layer: Handles end-to-end data transfer.

  • Internet Layer: Responsible for data routing.

  • Link (Physical Layer): Concerned with the physical media for data transfer.

Network Layer Functions

  • Connections: Connects multiple networks.

  • Forwarding/ Routing: Moves data from one network port to another and decides the optimal route.

  • Internet Protocol: Defines IP addresses (IPv4 and IPv6).

Transport Layer Functions

  • Provides essential functionalities alongside the forwarding tasks managed by the lower layers.

Application Layer Functions

  • Defines message types, syntax, and semantics for inter-device communication.

    • Open Protocols: Defined in RFCs (e.g., HTTP) for compatibility.

    • Proprietary Protocols: Exclusively defined protocols like Zoom or Skype.

File Transfer Protocol (FTP)

  • Steps involved in the FTP connection process include establishing initial connections, sending credentials, and confirming connection readiness.

Data Communication through Networks

  • Process: Data generated at application level, encapsulated by layer headers (Transport Layer: TCP/UDP, Internet Layer: IP, Link Layer: MAC details).

Discussion Points

  • Network Scale: Focus areas include PAN, LAN, MAN, WAN, and the Internet.

  • Layers of Interest: Physical, Data Link, Network, Transport, Application layers.

  • Packet Crafting: Discuss feasibility and implications of sending custom packets across networks, and how it varies with different protocols.

Closing

  • Instructor Contact: Dr. Abdullah Aydeger

  • University Affiliation: Florida Tech, Florida's STEM University.