Module 9 Study Notes — Networks & Network Devices

Page 1: Module Introduction

• Module 9 focuses on “Networks and Network Devices: Communicating and Connecting.”

• Source text: Jennifer T. Campbell, Discovering Computers: Digital Technology, Data, and Devices, 17th Edition (© 2023 Cengage).

• Reminder that the contents are protected intellectual property.

Page 2: Ice-Breaker—Interview Simulation

• Discussion prompt: The Internet has transformed work and social interactions, essentially shrinking the planet into a “digital village.”
  • Consider impacts on: collaboration, remote employment, global markets, real-time communication, cultural exchange, work–life balance, and new forms of digital etiquette.

• Encourages critical thinking before diving into technical details.

Page 3: Module Objectives

By the end of the module you should be able to:

1. Explain how users interact with a network.

2. Identify types of network structures.

3. Describe network standards and protocols.

4. Explain how hardware connects to a network.

5. Set up a network (step-by-step methodology).

6. Identify network-security tools.

7. Describe the professional role of a network administrator or engineer.

Page 4: Interacting with a Network (1 / 9)

• Definition: A network is a system of $\ge 2$ devices linked via wires, cables, or a telecommunication system.

• Purpose: shared resources (hardware, software, data, information).

• Networks require BOTH hardware & software.

• Global communication occurs via the Internet (a network of networks).

• Figure 9-1 visually depicts resource/data sharing.

Page 5: Interacting with a Network (2 / 9)

• Digital communications = process where devices transfer data/instructions.

• All categories of devices can act as senders & receivers.

• Typical communications devices: modems, wireless access points, routers.

• Transmission media can be wired (copper, fiber) or wireless (radio, IR, microwave).

Page 6: Interacting with a Network (3 / 9)—Communication System Components

Page 7: Interacting with a Network (4 / 9)—Home vs. Business Networks

Home:

• Single building, few users.

• Simpler installation/configuration.

Business:

• Many users, larger data volumes, multi-building campuses.

(Additional factors: structure, standards, range, topology.)

Page 8: Interacting with a Network (5 / 9)

• Figure 9-3 shows a typical home network (ISP → modem/router → wired & wireless devices).

Page 9: Interacting with a Network (6 / 9)—Capabilities & Advantages

Home capabilities:

1. Shared Internet access.

2. File sharing (e.g., photos).

3. Shared peripherals (printers).

4. Online gaming for consoles.

Business advantages:

1. Employee communication (email, VoIP, IM).

2. Shared hardware (printers, scanners).

3. Centralized sharing of data/software.

4. Central storage & backup for critical info.

Page 10: Interacting with a Network (7 / 9)—Enterprise-Level Concepts

• Intranet = internal IP-based network.

• Extranet = controlled outside access (customers, suppliers).

• VPN (Virtual Private Network) = encrypted tunnel through a public network enabling remote secure access.

Page 11: Interacting with a Network (8 / 9)—Wired vs. Wireless

Wired:

• Signals travel via cabling.

• Generally faster & more secure.

Wireless:

• Signals propagate through airwaves.

• More convenient; easier to deploy but potentially less secure.

• Cellular networks (3G/4G/5G) are special wireless WANs.

Page 12: Interacting with a Network (9 / 9)—Communications Software

• Functions: connection setup, data-flow management, user interface (chat, email, VoIP, collaboration suites).

Page 13: Network Structures (1 / 7)—Classification Axes

1. Topology (physical layout)

2. Architecture (client/server vs. peer-to-peer)

3. Geographic reach (LAN, MAN, WAN, etc.)

• Common topologies: bus, ring, star, mesh.

Page 14: Network Structures (2 / 7)—Topology Details I

Bus: all nodes attach to single “bus” cable; failure of bus = total outage.
Mesh: devices interconnected;
• Full mesh – each device→every other.
• Partial mesh – subsets interconnected.
Advantage: redundancy; single-link failure ≠ network failure.

Page 15: Network Structures (3 / 7)—Topology Details II

Ring: sequential data flow; one break can halt traffic; obsolete.
Star: devices connect to central hub/switch; hub failure = outage; individual device failure isolated.

• Multiple stars + bus backbone = tree topology (common in schools/businesses).

Page 16: Network Structures (4 / 7)—Client/Server Model

• Servers provide resources; clients request.

• Managed by network administrator.

• Scale: small to enterprise.

Page 17: Network Structures (5 / 7)—Peer-to-Peer (P2P)

• ≤ 10 devices; equal privileges.

• Internet P2P = file-sharing (legal and illegal implications).

• No dedicated admin needed but limited scalability & security.

Page 18: Network Structures (6 / 7)—LAN

• Local Area Network: limited physical area (room, floor, building).

• Figure 9-6 illustrates sample LAN.

Page 19: Network Structures (7 / 7)—Additional Configurations

• WLAN – wireless LAN.

• WAN – large geography (cities, countries).

• MAN – city/county-run wide area network.

• PAN – short-range personal devices (Bluetooth).

• BAN – body-area; implanted biosensors.

Page 20: Discussion 9-1—Bluetooth: Boon or Bane?

Pros: cable-free convenience, low power usage, cost-effective peripherals.
Cons: limited range, interference, security vulnerabilities, bandwidth ≤ $3$ Mbps.

Page 21: Network Standards & Protocols (1 / 11)—Definitions

• Standard: guideline for medium, speed, hardware.

• Protocol: detailed rules for communication (format, error handling, sequence).

• Ethernet = dominant wired LAN standard.

• Business data exchange example: EDI.

Page 22: Network Standards & Protocols (2 / 11)—Table 9-3 Highlights

Sample pairings:

• Bluetooth (protocol) → headsets.

• IrDA (standard) → remote controls.

• LTE (standard) → mobile broadband.

• NFC (protocol) → tap-to-pay.

• RFID (protocol) → toll collection.

• Wi-Fi (standard) → hotspots.

Page 23: Network Standards & Protocols (3 / 11)—TCP/IP & Addressing

• TCP: reliable transport & sequencing.

• IP: logical addressing (IPv4 vs. IPv6).

• Other close-distance protocols: Wi-Fi, LTE, Bluetooth, UWB, IrDA, RFID, NFC.

Page 24: Network Standards & Protocols (4 / 11)—Wi-Fi / IEEE 802.11

• Wi-Fi = any 802.11-based network.

• Variants & max theoretical speeds:
  • 802.11b (11 Mbps), 802.11g (54 Mbps), 802.11n (600 Mbps), 802.11ac (1.3 Gbps), 802.11ax or Wi-Fi 6/6E (∼7 Gbps).

• Devices labelled “b/g/n/ac/ax” denote multi-standard support.

• Range extension may require extra hardware (repeaters, boosters).

Page 25: Network Standards & Protocols (5 / 11)—Bluetooth Deep Dive

• Short-range (≤ 30 ft / 9 m), $\le 3$ Mbps.

• Uses pairing code for initial trust.

• Example use-cases: car audio, GPS to phone, wireless photo transfer, cordless barcode scanner.

Page 26: Network Standards & Protocols (6 / 11)

• Figure shows phone↔car stereo pairing process.

Page 27: Network Standards & Protocols (7 / 11)—UWB & IrDA

• UWB (Ultra-Wideband): high-speed, penetrates obstacles; great for large multimedia files, location tracking.

• IrDA: line-of-sight infrared; common in TV remotes; eclipsed by radio-based tech.

Page 28: Network Standards & Protocols (8 / 11)—RFID

• Tag = transponder (antenna + memory).

• Reader = transceiver; handheld or fixed.

• Use-cases: toll roads, inventory, pet ID chips.

Page 29: Network Standards & Protocols (9 / 11)

• Figure 9-8 shows RFID toll collection (vehicle tag, reader gantry, backend billing).

Page 30: Network Standards & Protocols (10 / 11)—NFC

• NFC builds on RFID; extremely short range (≈ 4 cm).

• Devices: smartphones, POS terminals.

• Objects: contactless cards, tickets, programmable tags (stickers, wristbands).

• Figure 9-9 gives usage scenarios (tap-to-pay, file handoff, tag scanning).

Page 31: Network Standards & Protocols (11 / 11)—Protocol Summary (Table 9-4)

Quick reference mapping protocol → common uses:

• Bluetooth (peripheral pairing)

• IrDA (IR remotes)

• LTE (cellular data)

• NFC (contactless payment)

• RFID (toll & tracking)

• UWB (short, high-bandwidth)

• Wi-Fi (LAN/WLAN access)

Page 32: Knowledge Check 9-1

Q: Which close-distance protocol does not use radio? → IrDA (uses infrared light).

Page 33: Knowledge Check Answer

Confirmed answer: c) IrDA.

Page 34: Network Connection Hardware (1 / 8)—Basic Devices

• Nodes: any addressable device (PC, smartphone, printer, IoT gadget).

• Hub: simple multi-port repeater; broadcasts to all.

• Switch: smarter; forwards frames only to destination port (MAC table).

• Router: inter-network layer-3 device; chooses optimal path.

Page 35: Network Connection Hardware (2 / 8)—Modems

• Bridge local network to ISP.

• Digital/broadband modems: cable, DSL, ISDN.

• Converts between analog/digital or different digital signal types.

Page 36: Network Connection Hardware (3 / 8)

• Figure 9-10: cable splitter → cable box + cable modem.

Page 37: Network Connection Hardware (4 / 8)

• DSL: over copper phone pairs.

• ISDN: circuit-switched digital phone service.

• Both are external devices; often paired with Wi-Fi router.

• Figure 9-11 shows combined cable modem + Wi-Fi router.

Page 38: Network Connection Hardware (5 / 8)—Dedicated Lines & Multiplexing

• Dedicated line: always-on point-to-point.

• Multiplexing = combining multiple signals over one medium.

• Digital dedicated options: cable, DSL/ADSL, ISDN, FTTP, T-carrier (T1/T3), ATM.

Page 39: Network Connection Hardware (6 / 8)—Table 9-5 (Part 1)

• Cable: coaxial CATV → Ethernet.

• DSL/ADSL: asymmetric speeds; uses POTS lines.

• ISDN: $64$ kbps channels; can bundle (e.g., $2\times64=128$ kbps).

Page 40: Network Connection Hardware (7 / 8)—Table 9-5 (Part 2)

• FTTP: fiber to premises; uses ONT (optical network terminal).

• ATM: cell-switched (53-byte cells); QoS-friendly; deployed in carrier backbones.

Page 41: Network Connection Hardware (8 / 8)—Table 9-5 (Part 3)

• T-Carrier hierarchy:
  • T1: $1.544$ Mbps (24 DS0 channels).
  • T3: $44.736$ Mbps.

• Expensive; used by ISPs and large enterprises.

Page 42: How-To—Set Up a Network (1 / 5)

• Smallest home network = direct cable between two devices.

• Typical wireless setup needs: modem, router, WAP (sometimes integrated), client devices.

• Consider: hardware type, dwelling size, number/kind of devices.

Page 43: How-To—Set Up a Network (2 / 5)—Three-Step Plan

1. Acquire & connect modem/router to ISP.

2. Enable Wi-Fi, set SSID + strong key (WPA2/WPA3).

3. On each device: enable Wi-Fi, select SSID, enter key.

Page 44: How-To—Set Up a Network (3 / 5)—Wireless Printer Benefits

• Shared printing across all devices.

• Vendor app allows direct print or cloud print services.

• Figure 9-12 depicts mobile device sending doc to wireless printer.

Page 45: How-To—Set Up a Network (4 / 5)—Printer Setup Checklist

1. Place printer within Wi-Fi range on stable surface.

2. Navigate to printer network settings; join SSID; enter key.

3. Install driver/app on PCs and mobiles.

Page 46: How-To—Set Up a Network (5 / 5)—Improving Signal

• Fully extend or upgrade antennas.

• Centrally locate router/WAP.

• Add booster/repeater to amplify range; Figure 9-13 shows example.

• Replace router if performance remains poor.

Page 47: Secure IT—Secure a Network (1 / 5)

Common counter-measures:

• Change default credentials (admin password, SSID).

• Enable encryption (WPA3 preferred).

• Use MAC-address filtering.

• Monitor connected-device list.

Page 48: Secure IT—Secure a Network (2 / 5)—Network Threats (Table 9-6)

• Adware: forced ads.

• Spyware: covert data collection.

• Virus: malicious self-replicating code needing host.

• Worm: self-propagates via network.

• Trojan: malicious code hidden in legit file.

• Ransomware: encrypts data; demands payment.

• Rootkit: stealth admin-level backdoor.

Page 49: Secure IT—Secure a Network (3 / 5)—Security Tools

• Encryption: data scrambling in transit (e.g., WPA3-SAE for Wi-Fi).

• NAS: centralised storage & backup.

• Authentication: username/password, multi-factor.

• Firewalls: packet filtering & stateful inspection.

• Biometrics: fingerprint, face, iris scanning.

• Figure 9-14 illustrates layered security.

Page 50: Secure IT—Secure a Network (4 / 5)—Monitoring & Sniffing

• Network-monitoring software: traffic volume, bandwidth per node, uptime.

• Packet sniffers: capture frames for analysis; used by admins (diagnostics) and hackers (eavesdropping).

Page 51: Secure IT—Secure a Network (5 / 5)—Detecting Intruders

1. Log into router admin UI.

2. Compare list of connected MACs vs. known devices.

3. Tighten security (change key, disable WPS, hide SSID).

4. Enable firewall & stealth mode.

Page 52: Ethics & Issues—Network Professional Responsibilities (1 / 2)

• Network administrator tasks: design, procurement, setup, securing, maintenance.

• Professional body example: USENIX (supports research & best practices).

• Admins hold a position of trust—access to sensitive data & configs.

Page 53: Ethics & Issues—Network Professional Responsibilities (2 / 2)

Code of conduct covers:

1. Professionalism

2. Social responsibility

3. Personal integrity

4. Privacy respect

5. Compliance with laws/policies

6. Clear communication

7. System integrity & reliability

8. Education & continuous learning

9. Responsibility to the broader computing community

Page 54: Case Study 9-1 (1 / 2)—Problem Statement

• Marina in large apartment; Wi-Fi 11–20 Mbps within 100 ft.

• Her room suffers poor performance; roommates fine.

• She must physically relocate to upload files.

Page 55: Case Study 9-1 (2 / 2)—Possible Causes (MCQ)

A) Router doesn’t cover all locations.
B) Signal too strong.
C) Signal needs boosting (most likely).
D) Router limited to five clients.

Page 56: Case Study 9-1—Answer & Rationale

• Correct: C → The wireless signal weakens over distance/obstacles; booster or repositioning router required.

Page 57: Self-Assessment

Reflective prompts:

• Which network/device topics to explore deeper?

• Identify sections that were challenging (e.g., T-carrier details, security layers, topologies).

Page 58: Summary & Objective Review

• Link (not provided here) redirects to module objectives for final revision.

Key Cross-Lecture Connections & Real-World Relevance

• Many protocols (Bluetooth, NFC, RFID) intersect with IoT and mobile payments—crucial for modern commerce.

• Security topics align with broader cybersecurity principles (CIA triad: Confidentiality, Integrity, Availability).

• Ethical standards echo ACM/IEEE professional codes, underscoring societal impact of network engineering.

Numerical References Recap

• Wi-Fi speeds $11\;\text{Mbps} \to 7\;\text{Gbps}$.

• Bluetooth ≈ $3\;\text{Mbps}$ range <9\;\text{m}.

• T1 $1.544\;\text{Mbps}$, T3 $44.736\;\text{Mbps}$.

• IPv4 address length $32\;\text{bits}$; IPv6 $128\;\text{bits}$.

Formulas & Technical Concepts

• Multiplexing conceptually: $\text{Combined\ Signal}=\sum<em>{i=1}^{n}\text{Channel}</em>i$ over shared medium.

• Encryption (simplified): $C = E_K(P)$ where $P$ = plaintext, $K$ = key, $C$ = ciphertext.

Practical Tips

• Always update router firmware to patch vulnerabilities.

• Prefer WPA3; if unavailable, use WPA2-AES with strong passphrase $\ge 12$ chars.

• Central placement & boosters resolve dead zones like Marina’s scenario.

Ethical Implication Highlight

• Unauthorized P2P file-sharing breaks copyright law; network pros must audit traffic responsibly.

End of comprehensive, page-by-page study notes.