Computer networks do not function without network devices. In IB Computer Science, students are expected to understand what key network devices do, how they differ from each other, and where they are used within a network.
Three of the most important devices are routers, switches, and modems. These are often confused in exams, so precise explanations are essential.
Why Network Devices Are Needed
Network devices exist to:
- Connect devices together
- Control data flow
- Direct data to the correct destination
- Enable communication between different networks
Each device has a specific role. They are not interchangeable.
What Is a Switch?
A switch is a device used within a local area network (LAN).
Its main function is to:
- Connect multiple devices on the same network
- Forward data to the correct device
Key characteristics of switches:
- Operate inside a LAN
- Use MAC addresses to identify devices
- Reduce unnecessary network traffic
When a device sends data, the switch:
- Receives the data
- Checks the destination MAC address
- Sends the data only to the intended device
This makes switches more efficient than older hub-based networks.
In IB exams, switches are associated with:
- Internal networks
- High-speed local communication
- Efficient data forwarding
What Is a Router?
A router connects different networks together.
Its main function is to:
- Route data between networks
- Connect a LAN to a WAN (such as the Internet)
Key characteristics of routers:
- Use IP addresses
- Make routing decisions
- Control data traffic between networks
For example, a home router:
- Connects a home LAN to the Internet
- Decides where incoming and outgoing data should go
In IB Computer Science, routers are often linked to:
- Internet connectivity
- Network security
- Traffic management
Routers operate at a higher level than switches and handle inter-network communication.
What Is a Modem?
A modem is a device that allows a network to connect to an Internet Service Provider (ISP).
Its main function is to:
- Convert digital data into a form suitable for transmission
- Convert incoming signals back into digital data
The term modem comes from:
- Modulator
- Demodulator
Modems are necessary because:
- ISPs use different transmission technologies
- Data must be converted to travel over these systems
In many modern homes, the modem and router are combined into a single device.
Comparing Routers, Switches, and Modems
IB students should clearly distinguish the devices:
- Switch: connects devices within a LAN
- Router: connects different networks
- Modem: connects a network to an ISP
Strong answers explain function and placement, not just definitions.
Common Student Mistakes
Students often:
- Say routers connect individual devices
- Confuse switches with routers
- Forget the role of the modem
- Use everyday language instead of technical terms
Clear technical explanations score higher.
Final Thoughts
Routers, switches, and modems each play a crucial role in network communication. Switches manage local traffic, routers direct data between networks, and modems enable Internet access.
Understanding these roles allows IB Computer Science students to explain how real-world networks function — exactly what examiners expect.
