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.