# Understanding Network Devices How connecting to your wifi connects you to complete world, you can access anything present anywhere in the world whether it’s a website, mobile application, videos, images anything. Yes it’s because of the internet. But what is this internet, how this internet works, what different devices used in internet, Internet is not just wires connected to different computer it’s much much bigger than that yes it is wires connected to different computer but there are so many other devices which are present to make internet work efficiently. Let’s name some of them, a very common one “Router“ , Modem, Switches, LoadBalancers, Hub etc. Yes these are the devices which makes internet. Internet is nothing other than connection of different networks. **INTERNET= INTER + NET** it means internet is the interconnection of different networks. There are so many different networking devices used to connect you to the world. Let’s take deep dive into different devices present in the network which helps you to connect with anyone present anywhere in the world in just seconds. ## Networking Devices In this section we are going to learn about various networking devices like Modem, Switches, Router, Hub, Firewall, Load Balancers. In Computer Networks there is a model known as OSI(Open Systems Interconnection) model. This model consists of 7 different layers which deals with different devices at different levels of networking. ![](https://cdn.hashnode.com/res/hashnode/image/upload/v1768985311147/ea6fccc5-13ee-4aaf-9a84-f337d5251d73.png align="center") let’s understand different devices used in different layers of OSI model. ### HUB: **Hub** is the most basic networking device. It connects multiple computers in LAN(Local Area Network), this device found nowhere except old networks like labs for learning. Hub was used in first layer of OSI model which is physical layer. Earlier, when hubs were used in different LAN all the computer in an LAN gets connected to hub so that they can be connected to each other. Hub used to receive data from sender and then broadcast that data to all devices connected to it, this is con for hub as this poses security risk. There were many disadvantages of hub like * It causes unnecessary traffic in the network. * Poor performance. * Very slow and inefficient. ### SWITCH: **Switch** is a intelligent version of hub. It is a device from datalink layer(second layer) from OSI model. Switch connects devices within a LAN. Switch learns MAC addresses of devices connected to it, then sends the data to the intended device. Some advantages of switch are: * It prevents congestion in the network. * It provide privacy, only sends data to the intended device. * Excellent performance. ![](https://cdn.hashnode.com/res/hashnode/image/upload/v1768993658950/2abfcc64-342d-4bbd-b1c2-4db8ec34899f.png align="center") ### MODEM: **Modem** is formed by combination of two words **Mo**dulator & **Dem**odulator. Let’s first understand what are Modulator and Demodulator. 1. Modulator: Modulator is a device which converts the digital signals(from our computers) to analog signals. A modulator encodes information onto a high-frequency carrier wave, changing its properties (amplitude, frequency, phase) for efficient long-distance transmission. 2. Demodulator: Demodulator is reverse of modulator. It converts analog signals(coming from our ISP’s via fibre cables) to digital signals. A demodulator extracts the original information signal from the carrier wave to make it understandable. ![](https://cdn.hashnode.com/res/hashnode/image/upload/v1768987207867/e9fb62d2-f979-4f89-a31c-aa4d37db0b58.png align="center") Modem is the combination of both. By converting these signals modem allow us to connect to the internet. One drawback of modem is if you wants to connect multiple devices to modem you can’t do that modem can only get connected to single device if you wants to connect to multiple device you will need router let’s now understand what is a router. ### ROUTER: **Router** this term is derived from word “Route“ which mean path. Router is a device which decide best path for data packets. A Router is a networking device that connects multiple devices and multiple networks and directs data packets to their correct destination using IP addresses. While a modem brings the Internet into your network, a router distributes and manages that Internet among devices. Now lets understand how router works. 1. The router receives a data packet. Data packet have multiple information(metadata) other than the data like sender’s & receiver’s IP addresses. See the image this is how a data packet looks like ![](https://cdn.hashnode.com/res/hashnode/image/upload/v1768993209909/af383dee-ab39-453d-a026-ef0d9f8173bd.png align="center") 2. Router then reads the Destination IP address. 3. Router has it’s routing table then it decide where to send data packets. Advantages of router: * You can connect multiple devices to single router. * Acts as the entry and exit point for all devices in a local network. * Prevents unnecessary traffic flooding. * Provides Wi-Fi access to devices. ### LOAD BALANCERS: **Load Balancers** as the name refers to Load(traffic) balancers. This device only have one task to distribute the load among servers, it helps in scaling application if traffic suddenly rises, it provide fault tolerance for applications and servers. Their are several load balancing algorithms like First cum First Serve, Round Robin etc. Load balancers are also used in Cloud Platforms as they provide cloud services to the customers. ### FIREWALL: **Firewall** protects networks from unauthorized access. Administrator can apply different security rules by enabling a firewall in the network. They can also block traffic based on IP, Port, Protocol, Application. Firewall works across level 3 to 7 of OSI model. Places where it is used are * Corporates network * Data Center * Cloud Infrastructure * Home routers Firewall secures a particular network from malware, prevents hacking & provide control of the network. --- These are the networking devices which work behind the scene so that you can see videos on internet, send messages to your loved ones, shop from online stores and can do many such things.