CSCN 230 Chapter 1 notes

Chapter 1: Introduction to Computer Networks and Data Communications

Overview

• Understanding the essential concepts of computer networks and data communications is crucial for both business users and IT professionals.

• This chapter highlights the types of networks, devices used, and fundamental protocols that govern data communication.

Key Learning Objectives

• Employ the basic terminology of computer networks.

• Identify common computer network devices and their functions.

• Outline the main network types and their characteristics.

• Describe the layers of the TCP/IP protocol suite.

• Explain the layers of the OSI model and their duties.

• Understand cloud computing concepts and their significance.

Introduction to Computer Networks

• Computer networks are pervasive in modern society, linking devices in businesses, schools, and everyday environments.

• Examples include: mass transit, banking, grocery stores, and smartphones.

The Language of Computer Networks

Network Types

• PAN (Personal Area Network): Small networks around personal devices (e.g., PDAs, laptops).

• LAN (Local Area Network): Networks spanning a limited area such as a room or building.

• CAN (Campus Area Network): Connects multiple buildings on a campus.

• MAN (Metropolitan Area Network): Spans an area typically between 1 and 30 miles, aligned with a city.

• WAN (Wide Area Network): Covers large geographic areas, even globally.

Data Communications and Protocols

• Data communications involves transferring digital or analog data using signals that adhere to predefined standards.

• Network Management: Design and support of network hardware and software.

• Cloud Computing: Provides services over the Internet, abstracting hardware details from the user.

Big Picture of Networks

• Networks are formed from various devices:

  • Workstations: Computers, tablets, smartphones.

  • Servers: Offer resources or services to clients.

  • Network Switches: Facilitate data flow between devices.

  • Routers: Connect different networks (LAN to WAN).

Examples of Communication Networks

• Different forms of networks include:

  • Desktop computers connected to the Internet.

  • Laptops using wireless connections.

  • Cellular networks and sensor networks.

  • Business mainframe and cloud networks.

The Desktop Computer and the Internet

Connection Types

• Requires a Network Interface Card (NIC) to connect to networks.

• Typical connections at work/school: Ethernet; at home: DSL, cable modems, or sometimes dial-up.

A Laptop Computer and Wireless Connection

• Wireless Ethernet connections are common at work and school.

• Laptops use wireless routers or access points connected to wired networks.

Cellular Networks

• The market for cellular networks is expanding, with a focus on technologies like 5G.

• Enhancements include higher data transfer speeds.

Industrial Sensor-based Systems

• Found in industrial settings, they support operations like assembly lines and robotic controls.

Cloud Networks

• Networks that utilize virtualization to connect resources in the cloud.

• Types of cloud networks include public, private, and hybrid.

Network Architectures

• Reference models describe layers that allow devices to communicate and share data seamlessly.

• Two main models: TCP/IP and OSI.

The TCP/IP Protocol Suite

Layers

• Application Layer: Supports applications like email and web browsing.

• Transport Layer: Ensures proper data transfer functions.

• Network Layer: Manages network connections and data packet transfers.

• Network Access Layer: Translates data into a frame for transmission.

• Physical Layer: Handles the physical transmission of bits.

The OSI Model

Layers

• Application Layer: Similar function as TCP/IP’s application layer.

• Presentation Layer: Prepares data for presentation to users.

• Session Layer: Manages sessions between users.

• Transport Layer: Criteria covered by TCP/IP.

• Network Layer: Synchronized with TCP/IP's structure.

• Data Link Layer: Attaches framing information for data.

• Physical Layer: Deals with physical connections and transmission.

Logical and Physical Connections

• Logical Connections: Exist in software, facilitating ideas and information exchange.

• Physical Connections: Exist in the hardware realm, focusing on tangible structures.

Summary of Key Points

• Computer networks underpin many daily services, incorporating various network types.

• While TCP/IP and OSI define standards for communication, logical connections enhance functionality without physical ties.

• Characteristics of cloud computing include scalability and availability, with service models like SaaS, PaaS, and IaaS catering to diverse needs.