From routers to firewalls—discover how every network stays connected

Networking Devices Explained in Detail
1️⃣ Hub

A basic device that connects multiple computers in a network.

Works on Layer 1 (Physical Layer) of OSI model.

Sends incoming data to all connected devices — causing collisions.

No intelligence, no filtering, no MAC table.

Mostly outdated today.

Simple Example: Like shouting information in a room — everyone hears it whether needed or not.

2️⃣ Switch

Used to connect devices within the same LAN.

Works on Layer 2 (Data Link).

Uses MAC Address Table to forward frames only to specific ports.

Reduces collisions → faster and more secure.

Supports VLANs, STP, PoE etc.

Example: Like calling only one person in a room by name — information goes directly to the right device.

3️⃣ Router

Connects different networks (LAN to WAN/Internet).

Works on Layer 3 (Network Layer).

Uses IP addressing and routing protocols (OSPF, BGP, EIGRP).

Performs NAT, DHCP, Firewall functions depending on configuration.

Example: Like a postal service — finds the best route for sending packets.

4️⃣ Firewall

Enforces security rules between networks.

Works mainly on Layer 3 & 4, next-gen firewalls also inspect Layer 7.

Blocks or allows traffic based on predefined policies.

Protects against attacks, malware, unauthorized access.

Example: Like a security guard checking who can enter the building.

5️⃣ Access Point (AP)

Provides wireless network connectivity.

Works on Layer 2.

Extends network coverage in Wi-Fi environments.

Supports standards like 802.11a/b/g/n/ac/ax.

Example: Like a wireless door into the same network your switch uses.

6️⃣ Modem

Converts signals between digital (LAN) and analog (ISP line) formats.

Used for Internet access via DSL, cable, fiber, 4G/5G.

Works on Physical Layer.

Example: Like a translator converting spoken language to written format.

7️⃣ Gateway

Connects networks using different protocols (IP ↔ VoIP, IPv4 ↔ IPv6).

Performs protocol translation.

Works across multiple OSI layers.

Example: Like a multilingual guide allowing two different language speakers to communicate.

8️⃣ Load Balancer

Distributes network traffic across multiple servers.

Prevents overload, improves speed & availability.

Works on Layer 4–7 depending on type (TCP/HTTPS balancing).

Example: Like sending customers to different checkout counters to reduce queue wait time.

9️⃣ Repeater

Regenerates and boosts weak signals over long distances.

Works on Layer 1.

Mostly used in long-distance fiber/Wi-Fi.

Example: Like using a megaphone to repeat a message farther.

🔟 Bridge

Similar to a switch but older and slower.

Connects and filters traffic between network segments.

Works on Layer 2.

⭐ Quick Comparison Table (Useful for Slides)
Device OSI Layer Function Intelligent?
Hub Layer 1 Broadcasts data ❌
Switch Layer 2 Forwards using MAC ✔
Router Layer 3 Routes using IP ✔
Firewall L3–L7 Security filtering ✔✔✔
AP Layer 2 Wireless access ✔
Modem Layer 1 Digital ↔ Analog ❌
Gateway Multi-Layer Protocol translation ✔
Load Balancer L4–L7 Traffic distribution ✔
Repeater Layer 1 Signal boosting ❌
Bridge Layer 2 Segment filtering ✔