csis1/16wk-week-15-16-networks.md

# Weeks 15–16: Networks, Email, and the Web
**Hours:** 4 (2 lectures)

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## Learning Objectives
- Explain what a computer network is and why they exist
- Describe the basic components of a network (routers, switches, modems, access points)
- Distinguish between LAN, WAN, and the Internet
- Explain how the Internet works at a high level (IP addresses, DNS, HTTP/HTTPS)
- Use email effectively and professionally
- Navigate the web with understanding (URLs, browsers, search engines)
- Evaluate online information for credibility

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## Lecture 15: Networks & the Internet

### Key Concepts

**What Is a Network?**
Two or more devices connected to share resources and communicate.

> 💡 **Analogy:** A network is like a postal system. Every device has an address. Routers are like post offices — they figure out where to send things. Cables (or Wi-Fi) are the roads.

**Types of Networks**
| Type | Scope | Example |
|------|-------|---------|
| **PAN** (Personal Area Network) | Within reach of a person | Bluetooth earbuds ↔ phone |
| **LAN** (Local Area Network) | One building or campus | Home Wi-Fi, office network |
| **WAN** (Wide Area Network) | Multiple locations, large area | Company offices across cities |
| **The Internet** | Global | Worldwide network of networks |

**Network Hardware**
- **Modem:** Connects your home network to your ISP (Internet Service Provider). Translates signals.
- **Router:** Directs traffic between devices and between your network and the Internet. Assigns local IP addresses.
- **Switch:** Connects multiple devices on a LAN. Smarter than a hub — sends data only where it needs to go.
- **Wireless Access Point (WAP):** Provides Wi-Fi connectivity.
- **NIC (Network Interface Card):** Hardware in your device that connects to the network (built-in on modern devices).
- **Ethernet Cable (RJ-45):** Wired connection. Faster and more reliable than Wi-Fi.

> 💡 **Home network walkthrough:** "At home, your ISP brings the Internet to your modem. The modem connects to your router. Your router creates your home network and shares the Internet with your devices via Wi-Fi or Ethernet."

**How the Internet Works**
- **IP Address:** A unique address for every device on a network (like a street address)
  - IPv4: 192.168.1.1 (four numbers, 0-255)
  - IPv6: Longer format for the modern era (we ran out of IPv4 addresses)
  - **Public IP** (your home's address to the world) vs **Private IP** (each device inside your home)
- **DNS (Domain Name System):** Translates human-readable names to IP addresses
  - You type `google.com` → DNS looks up `142.250.80.46` → your browser connects
  - DNS = "the phone book of the Internet"
- **HTTP / HTTPS:** Protocol for transferring web pages
  - HTTP = unencrypted (anyone can read the data in transit)
  - HTTPS = encrypted with SSL/TLS (look for the padlock 🔒)
  - Always look for HTTPS on login pages and when entering personal info

**How Data Travels: Packets**
- Data is broken into small **packets**
- Each packet is labeled with source and destination addresses
- Packets may take different routes and are reassembled at the destination
- Protocols (TCP/IP) ensure all packets arrive and are in the right order

> 💡 **Analogy:** Sending a large book by mail. You tear out each page, put it in a separate envelope with a page number, and mail them. Some might go through different post offices. The receiver puts them back in order.

**Wired vs Wireless**
| Feature | Wired (Ethernet) | Wireless (Wi-Fi) |
|---------|-----------------|-----------------|
| Speed | Faster (up to 10 Gbps) | Slower (varies, typically 100-1000 Mbps) |
| Reliability | More stable | Can have interference |
| Mobility | Fixed location | Move freely |
| Security | Harder to intercept | Needs encryption (WPA3) |
| Setup | Cables required | No cables |

### Diagram Ideas
1. **Home Network Diagram** — ISP → Modem → Router → (Wi-Fi to laptop, phone, tablet) + (Ethernet to desktop, smart TV). Label each component.
2. **How DNS Works** — Flow: User types URL → Browser asks DNS → DNS returns IP → Browser connects to server → Page loads.
3. **Data Packets Journey** — Illustration: Message split into packets, each taking different paths, reassembled at destination.
4. **LAN vs WAN vs Internet** — Nested circles: PAN inside LAN inside WAN inside Internet.

### Slide Concepts
| Slide | Content |
|-------|---------|
| 1 | Title: "Connected: Networks & the Internet" |
| 2 | What Is a Network? — definition + postal analogy |
| 3 | Types: PAN → LAN → WAN → Internet |
| 4 | Network Hardware — labeled home network diagram |
| 5 | IP Addresses — your device's address |
| 6 | DNS — the Internet's phone book |
| 7 | HTTP vs HTTPS — the padlock matters |
| 8 | How Data Travels — packets explained |
| 9 | Wired vs Wireless — comparison |

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## Lecture 16: Email & the World Wide Web

### Key Concepts

**Email Fundamentals**
- **Email address format:** username@domain.com
- **Protocols:** SMTP (sending), IMAP/POP3 (receiving) — mention briefly, don't belabor
- **Components of an email:**
  - **To:** Primary recipient(s)
  - **CC:** Carbon copy — others who should see it
  - **BCC:** Blind carbon copy — hidden recipients
  - **Subject:** Brief, descriptive summary
  - **Body:** The message
  - **Attachments:** Files sent with the email
  - **Signature:** Auto-appended closing info (name, title, contact)

**Professional Email Etiquette**
- Use a clear, specific subject line (not "Hi" or "Question")
- Address the recipient appropriately
- Be concise and use proper grammar
- Don't use ALL CAPS (reads as shouting)
- Be careful with Reply All — does everyone need to see your response?
- Review before sending (especially attachments — are they actually attached?)
- BCC for mass emails to protect recipients' privacy
- Don't forward chain emails, jokes, or unverified information

> 💡 **Teaching idea:** Show two versions of the same email — one casual/sloppy, one professional. Which would you trust? Which would get a response?

**Managing Email**
- Inbox Zero concept: process, respond, archive, or delete
- Folders/Labels for organization
- Stars/Flags for follow-up
- Spam/Junk: what it is, how filters work, why you shouldn't click links in suspicious emails

**The World Wide Web**
- The Web ≠ the Internet. The Internet is the infrastructure. The Web is a service that runs on it (like email, streaming, gaming).
- **Web Browser:** Software for viewing web pages (Chrome, Firefox, Edge, Safari)
- **URL (Uniform Resource Locator):** The address of a web page
  - `https://www.gavilan.edu/academic/csis/index.php`
  - Protocol → Domain → Path
- **Search Engine:** Tool for finding information (Google, Bing, DuckDuckGo)
  - Search engines ≠ the Internet. They're a tool for finding things on it.

**Evaluating Online Information (CRAAP Test)**
| Criterion | Question to Ask |
|-----------|----------------|
| **Currency** | When was this published or updated? |
| **Relevance** | Does this relate to my topic? |
| **Authority** | Who wrote it? Are they credible? |
| **Accuracy** | Is it supported by evidence? Can you verify it elsewhere? |
| **Purpose** | Why does this exist? To inform, sell, persuade, entertain? |

> 💡 **Activity:** Give students 3 sources on the same topic — a peer-reviewed article, a blog post, and a satirical news article. Have them evaluate each using the CRAAP test.

**Web 2.0 & Cloud Services**
- Social media, wikis, blogs, user-generated content
- Cloud applications: Google Docs, Microsoft 365 online, Canva
- Collaboration: real-time editing, sharing, commenting

### Diagram Ideas
1. **Email Anatomy** — Labeled email showing To, CC, BCC, Subject, Body, Attachment icon, Signature.
2. **URL Breakdown** — `https://www.example.com/products/shoes.html` with labeled parts: protocol, subdomain, domain, path, page.
3. **Internet vs Web** — Venn-style: Internet = infrastructure (email, gaming, streaming, web). Web = one service on the Internet.
4. **CRAAP Test Infographic** — One-page visual reference for evaluating sources.

### Slide Concepts
| Slide | Content |
|-------|---------|
| 1 | Title: "Email & the Web" |
| 2 | Email Anatomy — labeled example |
| 3 | Professional vs Unprofessional Email — side-by-side |
| 4 | Email Etiquette Rules — top 5 |
| 5 | Web vs Internet — they're not the same |
| 6 | URL Anatomy — breaking down an address |
| 7 | Search Engine Tips — quotation marks, minus sign, site: operator |
| 8 | CRAAP Test — evaluating sources |
| 9 | Activity: Evaluate 3 sources |

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## Vocabulary

| Term | Definition |
|------|-----------|
| **Network** | Two or more connected devices that can share resources and communicate |
| **LAN (Local Area Network)** | A network covering a small area like a home, office, or building |
| **WAN (Wide Area Network)** | A network spanning a large geographic area, connecting multiple LANs |
| **Internet** | The global network connecting millions of networks worldwide |
| **ISP (Internet Service Provider)** | A company that provides Internet access (Comcast, AT&T, etc.) |
| **Modem** | Device that connects a home network to the ISP |
| **Router** | Device that directs network traffic and connects devices to the Internet |
| **Switch** | Device that connects multiple devices on a LAN |
| **IP Address** | A unique numerical address assigned to every device on a network |
| **DNS (Domain Name System)** | Service that translates domain names (google.com) into IP addresses |
| **HTTP / HTTPS** | Protocols for transferring web pages; HTTPS adds encryption |
| **Packet** | A small unit of data transmitted over a network |
| **TCP/IP** | The foundational protocol suite for Internet communication |
| **Wi-Fi** | Wireless networking technology based on radio waves |
| **Ethernet** | Wired networking technology using cables (RJ-45 connectors) |
| **Bandwidth** | The maximum data transfer rate of a network connection |
| **Email** | Electronic mail; messages sent between users via the Internet |
| **SMTP** | Protocol for sending email |
| **CC / BCC** | Carbon Copy (visible to all) / Blind Carbon Copy (hidden from others) |
| **URL (Uniform Resource Locator)** | The address of a resource on the web |
| **Web Browser** | Software for accessing and viewing web pages |
| **Search Engine** | A tool for finding information on the web (Google, Bing) |
| **CRAAP Test** | Framework for evaluating information: Currency, Relevance, Authority, Accuracy, Purpose |
| **Cloud Computing** | Delivering computing services over the Internet (storage, apps, processing) |
| **Spam** | Unsolicited bulk email, often commercial or malicious |

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## Activities & Assignments

### In-Class
1. **Network Diagram Drawing:** Students draw their home network from memory, then compare with a partner. Identify modem, router, and connected devices.
2. **Professional Email Workshop:** Write a professional email for a given scenario (emailing a professor about a missed class, applying for a job, requesting information). Peer review.
3. **Source Evaluation:** Three sources on "Are video games harmful?" — evaluate each with the CRAAP test. Class discussion on which is most credible and why.

### Homework
1. **"How Does Netflix Get to My TV?" (1 page):** Trace the journey of a video from Netflix's servers to your screen. Mention: Internet, ISP, modem, router, Wi-Fi/Ethernet, streaming protocol. Use the terms from class.
2. **Email Etiquette Scenarios:** Given 5 email situations, write appropriate subject lines and opening sentences. Identify when to use CC vs BCC.
3. **Search Engine Challenge:** Answer 5 research questions using advanced search techniques (quotes, site:, minus sign, date filters). Document the search strategy used for each.

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## Discussion Questions
1. If DNS stopped working tomorrow, what would happen? Could you still use the Internet?
2. Why does HTTPS matter? What could happen on an unencrypted connection?
3. Is email "private"? Who might be able to read your emails? (ISP, employer, government, hackers)
4. Your grandparent shares a health article on Facebook. How would you evaluate whether to trust it?