- ✓Routers operate at Layer 3 of the OSI model and are responsible for forwarding data packets between different networks.
- ✓Switches operate at Layer 2 and connect devices within the same network, forwarding frames based on MAC addresses.
- ✓Hubs are largely obsolete but operated at Layer 1, simply broadcasting data to all connected devices.
- ✓Wireless access points extend network connectivity without physical cables and must be carefully positioned and secured.
- ✓Firewalls inspect incoming and outgoing network traffic and apply rules to allow or block it based on security policies.
Listen to the full episode inside the course. Enrol to access all 80 episodes, plus assignments, tutor support and Student Finance funding.
Start learning →Alex: Today we're covering networking devices, the physical and virtual components that make a network function. Sam, let's work through the main ones.
Sam: Let's start with the most important one: the router. A router operates at Layer 3, the Network layer, and its job is to forward packets between different networks. When data leaves your home and heads to a server on the internet, it passes through multiple routers, each one making a decision about the best path to the destination based on routing tables.
Alex: And switches are different from routers?
Sam: Quite different. A switch operates at Layer 2, the Data Link layer, and connects devices within the same network. Rather than routing packets between networks, a switch forwards frames within a local area network based on MAC addresses, the unique identifiers burned into every network interface card. Modern managed switches are sophisticated devices that support VLANs, traffic prioritisation, and detailed logging.
Alex: What about hubs? I've heard the term but they seem quite old.
Sam: Hubs are essentially obsolete in modern networks, but you'll still encounter them in study materials. A hub operates at Layer 1 and simply repeats any signal it receives to all of its ports simultaneously, with no intelligence about addressing. This means every device on a hub receives every frame, whether it's intended for them or not, creating what's called a collision domain. Switches replaced hubs precisely because they eliminate this inefficiency.
Alex: What about wireless access points?
Sam: Wireless access points, or WAPs, are the bridge between wired and wireless networks. They broadcast a Wi-Fi signal and allow wireless devices to connect to the wired LAN. In enterprise environments you might have dozens or hundreds of access points managed centrally by a wireless controller. Placement, channel selection, and security configuration are all important considerations.
Alex: And firewalls, they're devices too?
Sam: They can be. Hardware firewalls are dedicated network appliances that sit between your network and the outside world, inspecting traffic and applying rules to block or allow it. They operate at multiple layers depending on their sophistication; a basic firewall might only look at IP addresses and port numbers, while a next-generation firewall can inspect the content of packets and apply rules based on applications and users.
Alex: Are there any other devices worth mentioning?
Sam: A few. Modems convert the signal from your internet service provider into a form your router can understand. Network-attached storage devices provide shared storage across a network. Load balancers distribute incoming traffic across multiple servers to improve performance and resilience. In larger network environments you also encounter network interface cards in servers, patch panels in data centres, and proxy servers that sit between users and the internet.
Alex: It's quite a complex ecosystem.
Sam: It is, and what makes it fascinating is how all these devices work together. Understanding what each one does and where it sits in the network architecture is foundational knowledge for anyone working in IT infrastructure or network engineering.
Alex: Great. Next we're moving on to network topologies and how the arrangement of these devices affects performance.