📖 What Are Networking Devices?

Networking devices connect end devices and forward, control, secure, or extend communication.

👉 Unlike end devices, they forward traffic.

1️⃣ Gateway 🚪

Definition:
Connects two different networks using different protocols.

Main Functions:

Protocol conversion

Connects LAN to the Internet

Acts as an entry/exit point

May include firewall & NAT

Exam Point:
Works at multiple OSI layers.

2️⃣ Router 📡

Definition:
Connects multiple networks and forwards data using IP addresses.

Main Functions:

Routes packets

Uses the routing table

Selects the best path

Performs NAT

Supports static & dynamic routing

OSI Layer: Layer 3

Interview Line:
A router connects different networks using IP addresses.

3️⃣ Switch 🔀

Definition:
Connects devices within the same network using MAC addresses.

Main Functions:

Connects LAN devices

Learns MAC automatically

Reduces congestion

Supports VLAN

OSI Layer: Layer 2

4️⃣ Hub 📢

Definition:
A basic device that broadcasts data to all ports.

Characteristics:

No intelligence

No MAC table

High collisions

OSI Layer: Layer 1
👉 Obsolete technology

5️⃣ Firewall 🔥

Definition:
A security device that monitors and controls traffic.

Functions:

Blocks unauthorized access

Filters traffic

Prevents attacks

Supports VPN

OSI Layer: Mainly 3 & 4

6️⃣ Access Point (AP) 📶

Definition:
Allows wireless devices to connect to a wired network.

Functions:

Provides Wi-Fi

Extends coverage

Manages wireless clients

Layer: 2

7️⃣ Modem 🌐

Definition:
Converts digital ↔ analog signals
(MO = Modulator, DEM = Demodulator)

Function:
Connects ISP to customer network.

8️⃣ Bridge 🌉

Connects two LAN segments and filters traffic using MAC.

Layer: 2
(Replaced by switches)

9️⃣ Repeater 📡

Regenerates weak signals to extend distance.

Layer: 1

📊 OSI Quick Table