IT Essentials Lecture 5: Networking Concepts (Part I)
Network History
Early Foundations (1950s–1960s)
- Experimental networks for military use, leading to ARPANET.
- ARPANET pioneered packet-switching technology.
Development of Protocols (1970s)
- Key protocols like Ethernet (local networks) and TCP/IP (communication across networks).
- USENET: An early form of social networking.
Standardization and Growth (1980s)
- ARPANET adopted TCP/IP, forming the foundation of the internet.
- NSFNET connected universities and research centers.
User-Focused Internet (1990s)
- Introduction of the World Wide Web by Tim Berners-Lee.
- Graphical browsers, commercial ISPs, and search engines like Google improved usability.
Connectivity Revolution (2000s)
- Broadband and Wi-Fi enabled high-speed wireless access.
- Social media and smartphones drove increased global connectivity.
Modern Advancements (2010s–2020s)
- 2010s: Emergence of cloud computing, IoT, and 5G technology.
- 2020s: Focus on edge computing, AI integration, and enhanced global connectivity.
Network Components and Types
Principles of Networking
- A network is a collection/system of interconnected devices (e.g., computers, servers, phones) for sharing data, resources, and services.
- Networks vary in size and complexity, from small local setups like home or office LANs to global systems like the internet.
- Devices exchange information using protocols, enabling access to shared files, applications, printers, and more.
- Networks can be wired (using cables) or wireless (using radio waves) and are essential for modern communication, business, and information sharing.
- Examples of networks:
- Mail delivery system
- Telephone system
- Public transportation systems
- Corporate computer network
- The Internet
Benefits of Networking
- Shared resources (e.g., files, printers).
- Enhanced communication capabilities.
- Reduced file duplication and corruption.
- Centralized administration and cost-effective licensing.
Components of a Network
- Host Devices: Send and receive information (e.g., computers, printers).
- Intermediary Devices: Facilitate data transfer between host devices.
- Media: The physical or wireless mediums over which data is transmitted (e.g. cables).
Computers can connect to share data and resources via:
- Copper cabling
- Fiber-optic cabling
- Wireless connections
Basic Network Devices
Network Interface Card (NIC)
- Connects devices to wired or wireless networks.
Repeaters, Bridges, and Hubs
- Repeaters: Regenerate signals to extend range.
- Hubs: Broadcast data received on one port to all other ports.
- Bridges: Divide networks into segments, tracking connected devices.
Modems
- Convert digital data to analog signals for transmission (and vice versa).
- Use RJ-11 connectors; available as internal or external devices.
Switches
- Use MAC addresses to send data to specific devices.
- Types: Managed (for enterprise) and unmanaged (for homes).
Wireless Access Points (APs)
- Provide wireless network access within a limited range.
Routers
- Connect networks and forward traffic using IP addresses.
Firewalls
- Protect networks from unauthorized access using Access Control Lists (ACLs).
Network Cables
Types of Cables
Coaxial Cables
- Copper/aluminum wire, common in TV systems.
- Variants:
- Thicknet (10Base5): Up to 500 m, 10 Mbps.
- Thinnet (10Base2): Up to 185 m, 10 Mbps.
- RG-59: Common for cable TV in the US.
- RG-6: Higher bandwidth and less interference.
Twisted-Pair Cables
Types:
- Unshielded Twisted-Pair (UTP): Common, prone to EMI/RFI.
- Shielded Twisted-Pair (STP): Better protection but more expensive.
Wiring Schemes:
- T568A and T568B define pinouts for cable ends.
- Cable Types:
- Straight-through: Same wiring on both ends; connects unlike devices.
- Crossover: Different wiring on each end; connects like devices.
UTP vs. STP
| Attribute | Shielded Twisted Pair (STP) | Unshielded Twisted Pair (UTP) |
|---|---|---|
| Structure | Twisted pairs with shielding (foil or braided metal) | Twisted pairs without any additional shielding |
| Interference Protection | Excellent protection against EMI and RFI due to shielding | Minimal protection against EMI and RFI |
| Signal Quality | Higher signal quality in environments with high interference | More susceptible to interference, which can degrade quality |
| Cost | More expensive due to added shielding | More affordable, commonly used for general networking |
| Installation | More difficult to install; requires grounding | Easier to install; does not require grounding |
| Weight and Flexibility | Heavier and less flexible due to shielding | Lighter and more flexible, easier to work with |
| Use Cases | High-interference areas (industrial, medical facilities) | Standard LAN environments (offices, homes) |
| Bandwidth Capacity | Similar to UTP but with better interference protection | High bandwidth, commonly used in Ethernet cables (Cat 5e, 6) |
Twisted-Pair Category Ratings
| Cable Type | Speed | Features |
|---|---|---|
| Category 3 | 100 Mb/s at 100 MHz | Early widely adopted 4-pair UTP for Ethernet LANs. |
| Replaced by Cat 5 UTP, which is manufactured with higher standards for better data rates. | ||
| Category 5e | 1 Gb/s at 100 MHz | Higher standard than Cat 5 for improved data transfer rates. |
| More twists per foot for better EMI and RFI prevention. | ||
| Category 6 | 1 Gb/s at 250 MHz (Cat 6a - 500 MHz) | Higher standard than Cat 5e for better data transfer rates. |
| More twists per foot and a possible plastic divider to reduce EMI and RFI. | ||
| Suitable for bandwidth-intensive applications like videoconferencing or gaming. | ||
| Cat 6a offers better insulation and performance than Cat 6. |
Fiber-Optic Cables
- Transmit information using light, unaffected by EMI/RFI.
- Types:
- Single-Mode Fiber (SMF): Laser-based, long-distance, high-speed.
- Multi-Mode Fiber (MMF): LED-based, shorter distance, cost-effective.
Network Tools
- Tools and Their Uses:
- Wire Cutters: Trim wires to length.
- Wire Strippers: Remove cable jackets.
- Crimpers: Attach RJ-45 connectors securely.
- Punch-Down Tools: Terminate wires into patch panels.
- Multimeter: Check electrical circuits and voltage.
- Cable Tester: Verify correct wiring and detect faults.
- Wi-Fi Analyzer: Assess signal strength and troubleshoot Wi-Fi issues.
- Tone Generator: Trace cables using sound signals.
- Loopback Adapter: Test network ports and NIC functionality.
Cable Types Summary
| Attribute | Twisted Pair Cable | Coaxial Cable | Fiber Optic Cable |
|---|---|---|---|
| Structure | Two insulated copper wires twisted together | Single copper core with insulating and shielding | Glass or plastic core transmitting light signals |
| Transmission Medium | Electrical signals | Electrical signals | Light signals (optical) |
| Bandwidth Capacity | Low to moderate (up to 10 Gbps for Cat 6a) | Moderate (up to 10 Gbps) | Very high (up to Tbps in single-mode fiber) |
| Distance Limitation | Limited (up to 100 meters for Ethernet) | Moderate (up to 500 meters for broadband) | Long-distance (tens of kilometers) |
| Signal Quality | Susceptible to EMI and RFI | Less susceptible than twisted pair | Immune to EMI and RFI |
| Cost | Low | Moderate | Higher than twisted pair and coaxial |
| Installation | Easy | Moderate (requires thicker cabling) | Difficult (requires specialized equipment) |
| Use Cases | LANs, landline telephones | TV, broadband internet | High-speed internet, long-distance data transfer |