1.4 THE INTERNET
Learning Objectives
Evaluate the basic components and functions of the internet.
Assess the proper use of internet browsers and search engines for efficient information retrieval.
Basic Components of the Internet
Client: A device or software that requests services or resources from a server (e.g., computer, smartphone).
Server: A computer or program that provides services/resources to clients upon request.
Types of Servers
Web Servers: Host websites and deliver web pages.
Email Servers: Handle email services.
File Servers: Store and manage files for client access.
Database Servers: Manage databases and respond to queries.
IP Addresses and DNS
IP Address: Unique numerical identifier for devices on a network.
IPv4: 32-bit address, ~4.3 billion unique addresses.
IPv6: 128-bit address, almost infinite addresses; designed to replace IPv4.
Static IP Address: Permanent address; often used for servers.
Dynamic IP Address: Temporary address; changes with each connection.
Routers and Gateways
Routers: Forward data packets between networks and manage traffic.
Gateways: Connect different networks, allowing communication.
Types of Routers
Home Routers: Connect residential devices to the internet.
Core Routers: Route data between large networks.
Types of Gateways
Internet Gateway: Connects a local network to the internet.
Mail Gateway: Manages email traffic.
VPN Gateway: Enables secure communication over public networks.
Modems
Modem: Enables internet connection over communication lines; converts signals.
Cable Modems: Use coaxial cables.
Wireless Modems: Connect to cellular networks.
DSL Modems: Use telephone lines for quicker data transfer.
Data Transfer
Packets: Data is split into packets (1,000-1,500 bytes) for transmission.
Strengths: Efficient bandwidth use, error detection, aids routing.
Weaknesses: Potential packet loss; reassembly required.
Transmission Protocols
TCP (Transmission Control Protocol): Reliable and connection-oriented.
UDP (User Datagram Protocol): Connectionless, faster but less reliable.
Internet Layers
Physical Layer: Data transmission methods (Wi-Fi, Ethernet).
Data Link Layer: Transfers data frames.
Network Layer: Routes packets.
Transport Layer: Ensures reliable transfer (TCP/UDP).
Application Layer: Application-specific communications (HTTP, FTP).
Bandwidth and Latency
Bandwidth: Data transfer rate (ex. Mbps).
Latency: Time taken for data travel; optimization techniques include compression and CDN use.
Security in Data Transfer
Encryption: Secures data.
Symmetric: Single key for encryption/decryption.
Asymmetric: Public/private key pair.
Firewalls
Firewalls: Monitor/filter network traffic based on security policies.
Stateful Inspection Firewalls: Monitor active connections.
Next-Generation Firewalls: Advanced protection features.
Internet of Things (IoT) and Cloud Computing
IoT: Network of connected devices sharing data for real-time control.
Cloud Computing: Platforms for data storage, processing, and analysis from IoT devices.
Web Browsers and Search Engines
Web Browsers: Tools for accessing websites (e.g., Chrome, Firefox).
Search Engines: Programs helping to find information online (e.g., Google).
Effective Search Techniques
Search Queries: Navigational, informational, and transactional queries.
Search Filters: Refine search results based on preferences.
Evaluating Information Credibility
Source Reliability: Trustworthiness of an information source.
Fact-Checking: Ensuring accuracy of information.
Currency: Timeliness of information relevance.
Summary of Data Transfer Steps
Request Generation
DNS Resolution
Packet Creation
Routing
Reception
Response
Display
Key Procedures
DNS translates URLs to IP addresses.
Devices break down data into packets with addresses before transmission.
Servers receive packets, reassemble data, and send responses back.