Routers vs Switches: What's the Difference?

20 Jul 2025 • Network • 9 min read

If you've ever set up a home network or worked in IT, you've probably seen routers and switches. They look similar, they both have blinking lights and Ethernet ports, but they do very different jobs. Let's clear up the confusion.

Think of your network like a city. A switch is like the roads within a neighborhood, connecting houses together. A router is like the highway exit that connects your neighborhood to other neighborhoods and the outside world.

The Short Answer

Switch = Connects devices within the SAME network (LAN)
Router = Connects DIFFERENT networks together (LAN to WAN/Internet)

That's the core difference. Now let's dive deeper.

What is a Switch?

A switch connects multiple devices (computers, printers, servers) within the same local network. It's the backbone of your LAN (Local Area Network).

How Does a Switch Work?

When you plug devices into a switch, it learns the MAC address of each device. The MAC address is a unique hardware identifier burned into every network card.

Device A sends data to Device B
The switch looks at the destination MAC address
The switch checks its MAC address table to find which port Device B is connected to
The switch sends the data ONLY to that port

MAC Address Table (CAM Table)

The switch maintains a table mapping MAC addresses to physical ports. Example:

Port 1 → AA:BB:CC:DD:EE:01 (PC-1)
Port 2 → AA:BB:CC:DD:EE:02 (PC-2)
Port 3 → AA:BB:CC:DD:EE:03 (Printer)
Port 4 → AA:BB:CC:DD:EE:04 (Server)

Switch vs Hub: What's the Difference?

You might have heard of hubs. They look like switches but are much dumber:

Hub	Switch
Sends data to ALL ports	Sends data only to the correct port
Creates network congestion	Efficient, no wasted bandwidth
OSI Layer 1 (Physical)	OSI Layer 2 (Data Link)
Obsolete technology	Modern standard

A hub is like shouting in a room. Everyone hears you, even if you're only talking to one person. A switch is like having a private conversation. Only the intended person hears you.

Types of Switches

Unmanaged Switch: Plug and play, no configuration. Good for home/small office.
Managed Switch: Configurable via web interface or CLI. Supports VLANs, QoS, port mirroring. Used in enterprises.
PoE Switch: Power over Ethernet. Can power devices like IP cameras and phones through the Ethernet cable.
Layer 3 Switch: Can also do routing. A hybrid between switch and router.

What is a Router?

A router connects different networks together. Most commonly, it connects your local network (LAN) to the internet (WAN).

How Does a Router Work?

While switches use MAC addresses, routers use IP addresses. They make decisions about where to send data based on the destination IP.

Your computer wants to visit google.com
The router receives the request
It checks its routing table to find the best path
It forwards the data toward the destination network
The response comes back the same way

Routing Table

A router maintains a table of network destinations and how to reach them:

Destination        Gateway         Interface
192.168.1.0/24     Connected       eth0 (LAN)
10.0.0.0/8         192.168.1.254   eth0
0.0.0.0/0          ISP Gateway     eth1 (WAN)

The 0.0.0.0/0 is the default route. If the router doesn't know where to send something, it goes there (usually your ISP).

Key Router Functions

NAT (Network Address Translation): Allows multiple devices to share one public IP address
DHCP: Automatically assigns IP addresses to devices
Firewall: Blocks unauthorized incoming connections
Port Forwarding: Directs specific traffic to specific devices
DNS: Resolves domain names to IP addresses

NAT Explained Simply

Your home has many devices but only ONE public IP address from your ISP. How does the router know which device requested what?

Imagine an apartment building with one address (123 Main St). When mail arrives, the doorman (router) checks the apartment number to deliver it to the right person. NAT works the same way, using port numbers as "apartment numbers".

# Your devices have private IPs:
PC:      192.168.1.10:50234 → wants google.com
Phone:   192.168.1.11:48123 → wants youtube.com

# Router translates to public IP with different ports:
PC:      203.0.113.5:60001 → google.com
Phone:   203.0.113.5:60002 → youtube.com

# When responses come back, router uses the port to know who gets what

Router vs Switch: Side by Side

Feature	Switch	Router
OSI Layer	Layer 2 (Data Link)	Layer 3 (Network)
Uses	MAC addresses	IP addresses
Connects	Devices in same network	Different networks
Broadcast	Forwards broadcasts	Blocks broadcasts
Table	MAC address table	Routing table
NAT	No	Yes
DHCP	No (usually)	Yes
Speed	Very fast (hardware-based)	Slower (software processing)

How They Work Together

In a typical network, routers and switches work as a team:


   [Internet]
       |
   [Router] ← Connects LAN to Internet, assigns IPs, firewall
       |
   [Switch] ← Connects all local devices together
    /  |  \
  PC  PC  Server

Real Office Network Example


                        [Internet]
                            |
                     [Edge Router]
                            |
                    [Core Switch]
                    /     |      \
            [Switch]  [Switch]  [Switch]
            Floor 1   Floor 2   Floor 3
            /    \     /    \     /    \
          PCs   PCs  PCs   PCs  PCs   PCs

In enterprise networks, you often have a hierarchy: core switches at the center, distribution switches in the middle, and access switches connecting end devices.

What About My Home Router?

Here's where it gets confusing. Your home "router" is actually 3 devices in one box:

Router: Connects your home to the internet
Switch: The 4 Ethernet ports on the back
Wireless Access Point: Provides Wi-Fi

It's like a Swiss Army knife. One device, multiple tools. In enterprise networks, these are usually separate devices for better performance and control.

VLANs: Making Switches Smarter

A VLAN (Virtual LAN) lets you create separate networks using one physical switch. Devices in different VLANs can't communicate directly, even if they're plugged into the same switch.

Why Use VLANs?

Security: Keep sensitive devices (servers, cameras) isolated
Organization: Separate departments (HR, Engineering, Guest WiFi)
Performance: Reduce broadcast traffic

# One switch, three VLANs:
VLAN 10 (Office):    Ports 1-10  → 192.168.10.0/24
VLAN 20 (Servers):   Ports 11-15 → 192.168.20.0/24
VLAN 30 (Guest):     Ports 16-20 → 192.168.30.0/24

# Devices in VLAN 10 cannot talk to VLAN 20 without a router

VLANs require a managed switch and a router (or Layer 3 switch) to allow communication between VLANs.

Common Network Commands

View Your Network Info

# Linux/Mac: Show IP and MAC address
ip addr
ifconfig

# Windows: Show IP configuration
ipconfig /all

# Show routing table
ip route        # Linux
route print     # Windows
netstat -rn     # Mac

View ARP Table (IP to MAC mappings)

# See which MAC addresses your computer knows about
arp -a

Trace the Path to a Destination

# See every router between you and a destination
traceroute google.com    # Linux/Mac
tracert google.com       # Windows

Troubleshooting Tips

Problem	Likely Cause	Check
Can't reach other local devices	Switch issue	Check cables, switch ports, VLANs
Can reach local devices but not internet	Router issue	Check router, default gateway, DNS
Slow network performance	Could be either	Check for broadcast storms, duplex mismatch
IP address conflict	DHCP issue	Check router DHCP settings

Summary

Remember these key points:

Switches connect devices within the same network using MAC addresses (Layer 2)
Routers connect different networks using IP addresses (Layer 3)
Switches are fast but only work locally. Routers are slower but connect you to the world.
Your home "router" is actually a router + switch + WiFi access point combined
VLANs let you create multiple logical networks on one physical switch

Now when someone asks you "what's the difference between a router and a switch?", you'll have a clear answer!