TNPSC Study Summary Notes: Network Devices

 TNPSC study summary notes on the topic Network Devices, aligned with typical syllabus content and exam expectations:

TNPSC Study Summary Notes: Network Devices

1. Introduction to Network Devices

Network devices are hardware components used to connect computers and other devices together in a network, enabling communication and resource sharing.

2. Common Types of Network Devices

Device	Function	Example/Notes
Router	Connects multiple networks, directs data packets between them	Routes traffic between LAN and WAN or internet
Switch	Connects devices within a local network, directs data based on MAC address	Operates at Data Link Layer of OSI model
Hub	Connects devices in a LAN but broadcasts data to all ports	Operates at Physical Layer; less efficient than switch
Modem	Converts signals between digital and analog for internet access	Connects home or office network to ISP
Access Point	Provides wireless connection to a wired network	Enables Wi-Fi connections for devices
Firewall	Manages and controls network traffic based on security rules	Can be hardware or software-based
Repeater	Amplifies signals to extend network range	Used in long-distance wired or wireless setups
Gateway	Acts as a translator for different network protocols	Connects networks with different architectures
Bridge	Connects two LAN segments to work as a single network	Filters data and reduces traffic

3. Functions and Roles

• Router:

  • Selects the best path for data packets.

  • Connects different IP networks.

  • Used in home and enterprise networks.

• Switch:

  • Creates a network by connecting devices.

  • Reduces collisions by sending data only to the intended device.

  • Operates at Layer 2 (Data Link Layer) but some operate at Layer 3 (Multilayer Switches).

• Hub:

  • Simple connection device.

  • Sends data packets to all devices—less secure and inefficient.

• Modem:

  • Modulates and demodulates signals for transmission over telephone or cable lines.

  • Essential for internet connectivity via DSL, cable, or fiber.

• Access Point (AP):

  • Connects wireless devices to a wired network using Wi-Fi protocols.

• Firewall:

  • Protects networks from unauthorized access.

  • Filters incoming/outgoing traffic according to security policies.

• Repeater:

  • Regenerates weakened signals to extend transmission distance.

• Gateway:

  • Enables communication between networks using different protocols.

• Bridge:

  • Divides traffic to reduce collisions and improve network performance.

4. Network Device Categories by OSI Model Layer

Layer	Network Devices Operating Here
Layer 1 (Physical)	Hub, Repeater
Layer 2 (Data Link)	Switch, Bridge
Layer 3 (Network)	Router, Multilayer Switch
Layer 4-7 (Transport to Application)	Firewall (stateful inspection), Gateway

5. Key Characteristics and Terminology

• MAC Address: Hardware address used by switches to route data within LAN.

• IP Address: Logical address used by routers for routing across networks.

• Bandwidth: Maximum data transfer rate of a network or device.

• Latency: Delay in data transmission.

• Full Duplex: Ability to send and receive data simultaneously (switches support this; hubs do not).

• Collision Domain: Network segment where data packets can collide; switches reduce collision domains.

• Broadcast Domain: Segment where broadcast packets are visible; separated by routers.

6. Examples and Usage

• Home Networks: Use modem + router + wireless access points for internet and Wi-Fi.

• Office Networks: Utilize switches for wired LAN connections, deploy firewalls for security.

• Large Enterprises: Use routers to connect different office branches, multilayer switches for efficient LAN management.

7. TNPSC Exam Tips

• Understand the role and function of each device clearly.

• Know which OSI layer each device operates at.

• Differentiate between similar devices like hub vs switch, router vs gateway.

• Focus on purpose, advantages, and drawbacks of devices.

• Practice MCQs based on real-life scenarios.

8. Sample MCQs

• Q: Which device directs data between different networks?
  A: Router

• Q: Which device connects multiple devices but sends data to all connected devices, causing collisions?
  A: Hub

• Q: What device converts digital data to analog signals for transmission over telephone lines?
  A: Modem

• Q: Which device operates at the data link layer and manages data traffic using MAC addresses?
  A: Switch

• Q: What network device extends the range of a network by amplifying signals?
  A: Repeater