Network Hardware (Switches, Routers, NICs, WAPs)
For a network to function, various pieces of hardware are needed to connect devices, manage data traffic and provide communication. This lesson covers the key network hardware components you need to know for GCSE Computer Science.
Network Interface Card (NIC)
A Network Interface Card (NIC) is a hardware component that allows a device to connect to a network. Every device on a network must have a NIC.
Key facts about NICs
- A NIC can be wired (Ethernet) or wireless (Wi-Fi).
- Most modern devices (laptops, desktops, phones) have NICs built in.
- Each NIC has a unique MAC address (Media Access Control address) — a 48-bit hardware address burned into the card during manufacture.
- The MAC address is used to identify devices on the local network.
| Feature | Detail |
|---|
| Purpose | Allows a device to connect to a network |
| Types | Wired (Ethernet port) or wireless (Wi-Fi adapter) |
| MAC address | Unique hardware identifier assigned to each NIC |
| Location | Built into the motherboard or plugged in as an expansion card / USB adapter |
Exam Tip: A MAC address is a physical address that is permanently assigned to the NIC. It is different from an IP address, which is a logical address that can change.
Switch
A switch is a device that connects multiple devices within a LAN. It is the central device in a star topology.
How a switch works
- A device sends data (a frame) to the switch.
- The switch reads the destination MAC address in the frame.
- The switch looks up the MAC address in its MAC address table to find which port the destination device is connected to.
- The switch forwards the frame only to that specific port.
Key facts about switches
- Switches operate at Layer 2 (the Data Link layer) of the network model.
- They use MAC addresses to forward data.
- Unlike a hub, a switch sends data only to the intended recipient, not to all devices. This improves performance and security.
- Modern switches can handle many simultaneous connections without slowing down.
Switch vs Hub
| Feature | Switch | Hub |
|---|
| Sends data to | Only the intended device | All connected devices |
| Uses | MAC address table | No intelligence — broadcasts everything |
| Performance | High — reduces unnecessary traffic | Low — causes congestion |
| Security | Better — data only reaches the intended device | Poor — all devices see all data |
| Cost | More expensive | Cheaper (but now obsolete) |
Note: Hubs are largely obsolete and have been replaced by switches in modern networks. However, you may still be asked to compare them in the exam.
Router
A router is a device that forwards data between different networks. It is essential for connecting a LAN to a WAN (such as the internet).
How a router works
- The router receives a packet of data.
- It reads the destination IP address in the packet header.
- It consults its routing table to determine the best path to forward the packet.
- It sends the packet to the next router or directly to the destination network.
Key facts about routers
- Routers operate at Layer 3 (the Network layer) of the network model.
- They use IP addresses to route data between networks.
- A home router typically combines several functions: routing, switching, wireless access point and modem.
- Routers can perform NAT (Network Address Translation) — translating private IP addresses on the LAN to a public IP address for the internet.
- Routers can act as a basic firewall, filtering incoming and outgoing traffic.
| Feature | Detail |
|---|
| Purpose | Forwards data between different networks |
| Uses | IP addresses and routing tables |
| Layer | Network layer (Layer 3) |
| Common use | Connecting a LAN to the internet |
Router vs Switch
| Feature | Router | Switch |
|---|
| Connects | Different networks (e.g. LAN to WAN) | Devices within the same LAN |
| Uses | IP addresses | MAC addresses |
| Layer | Layer 3 (Network) | Layer 2 (Data Link) |
| Function | Routes packets between networks | Forwards frames within a LAN |
Wireless Access Point (WAP)
A Wireless Access Point (WAP) is a device that allows wireless devices to connect to a wired network using Wi-Fi.
How a WAP works
- The WAP is connected to the wired network (usually to a switch) via an Ethernet cable.
- It broadcasts a wireless signal (using radio waves) that nearby devices can detect.
- Wireless devices connect to the WAP using the network's SSID (network name) and password.
- The WAP acts as a bridge between the wired and wireless parts of the network.
Key facts about WAPs
- A WAP extends the network to allow wireless connections.
- Multiple WAPs can be placed around a building to provide full wireless coverage.
- WAPs use Wi-Fi standards (such as 802.11ac or 802.11ax / Wi-Fi 6) to communicate.
- A home "Wi-Fi router" is usually a combined router, switch and WAP in one device.
- WAPs should use encryption (such as WPA2 or WPA3) to secure wireless communications.
Transmission Media
Data on a network is carried through transmission media. The two main types are:
Copper Ethernet Cables (e.g. Cat5e, Cat6)
- Carry electrical signals along copper wires.
- Commonly used in LANs for short-to-medium distances.
- Cat5e supports up to 1 Gbps; Cat6 supports up to 10 Gbps over short distances.
- Susceptible to electromagnetic interference (EMI).
Fibre Optic Cables
- Carry data as pulses of light through thin glass or plastic fibres.
- Much faster than copper cables — can carry data at speeds of 100 Gbps or more.
- Can transmit data over much longer distances without signal degradation.
- Not susceptible to electromagnetic interference.
- More expensive and more fragile than copper cables.
| Feature | Copper Cable | Fibre Optic Cable |
|---|
| Signal | Electrical | Light |
| Speed | Up to 10 Gbps | Up to 100+ Gbps |
| Distance | Short to medium | Long distances |
| Interference | Susceptible to EMI | Immune to EMI |
| Cost | Cheaper | More expensive |
| Durability | Robust | More fragile |
Summary
- A NIC allows a device to connect to a network and has a unique MAC address.
- A switch connects devices within a LAN using MAC addresses.
- A router forwards data between different networks using IP addresses.
- A WAP allows wireless devices to connect to a wired network.
- Copper cables and fibre optic cables are the main transmission media.
Exam Tip: Make sure you can clearly distinguish between a switch (LAN, MAC addresses) and a router (between networks, IP addresses). This is a very common exam question.
Deeper dive: hardware in action with worked examples