Networking Basics 1 : What is a Router?

What is a router?  What does the router do on the network?



What is a router?


Routers (routers) are network devices that forward data packets between computer networks. Understandably, the router performs “directing of traffic” on the Internet. Data is sent over the Internet in the form of packages, for example websites or emails. Data packets will be forwarded from router to router through small networks, which are connected together to form a linked network, until the packet reaches its destination. The process of transferring data packets, how to get the data packet to the right “address” you read will be explored in more detail in the Routing process of the Router .

There are many types of routers, from simple to complex. Regular routers are used for home Internet connection, while many routers with “huge” prices are usually business routers, used in large businesses and organizations. But, whether expensive or cheap, simple or complex, all routers operate with the same basic principles.

Here, we will focus on common routers, familiar to everyone, if you want to know more about business routers, scroll down to the bottom of the article.

Function of the router


In simple terms, a router connects devices in a network by transferring packets of data between them . This data can be sent between devices or from device to the Internet. The router does this by assigning a local IP address to each device on the network. This ensures data packets arrive at the right place, not lost in the network.

Imagine this data as a courier package, it needs a delivery address in order to be sent to the correct recipient. A local computer network is like a suburban street, it is not enough just to know the location of the street without knowing a specific house number in the big world (ie World Wide Web).

This package can be sent to the wrong address with a limited amount of information. Therefore, the router ensures each location (device) has a unique number so that data packets are sent to the correct location. If you need to return the data to the sender or send your own packet, the router does this too. Although it processes each packet individually, it does this very quickly, even when multiple devices send data at the same time.

Pictures of the Router


For a clearer picture, you can see the illustrations in Figures A and B. Figure A is the front of a TP-Link Archer C7 AC1750 broadband router, and Figure B is the back of it.

What Is A router?
Figure A : Front view of TP-Link Archer C7 AC1750 router


Back of the router
Figure B : TP-Link Archer C7 AC1750 back panel contains a set of

RJ-45 ports like a hub or switch

Figure A is the front of the router, consisting of beacons, from left to right: power light, wifi beacon (2.4GHz), wifi beacon (5GHz), 4 Ethernet beacons, internet beacon, system beacon .

Looking at Figure B you will see that there are three sets of ports on the back of the router. The port on the left-most side is where the power supply is connected to the router. The green RJ-45 port for plugging in a network cord from a cable modem or DSL modem.

Four yellow RJ-45 ports are used to plug network cables to computers on the network, thereby providing network connectivity for them.

Router’s routing process


To understand how routing is done, you must first know a little bit about how TCP / IP works .

Every device connected to a TCP / IP network has a unique IP address limited to its network interface. An IP address is a separate sequence of four numbers separated by dots. For example, a typical IP address is of the form:

The easiest example to understand when talking about IP is the home address. Regular home addresses always include house numbers and street names. House number determines the specific position of the house on that street. IP addresses work similarly. It includes the network address number and the device number. Compare with the home address, you will see that the network address is like the street name and the device number is like a house number. A network address indicates a specific network the device is participating in and the device number gives the device an identity on the network.

So where is the end of the network address and the beginning of the device number? This is the job of a subnet mask. The subnet mask will “tell” the computer the last location of the network address and the first location of the device number in the IP address. Subnet operations are sometimes very complex. You can refer to more details in another article that we will introduce later. Now for the simplest of things, consider a very basic subnet mask.

The subnet mask at first glance looks very similar to an IP address because it also has 4 numbers formatted in a pattern separated by dots. A typical subnet mask has the form:

In this particular example, the first three numbers (called octets) are all 255, the last number being 0. The number 255 indicates that all the bits in the corresponding IP address are part of the code. fate. The final zero indicates that there are no bits in the corresponding IP address that are part of the network address. Hence they belong to the device number.

It sounds rather messy, you will understand with the following example. Imagine you have a computer with an IP address of and a subnet mask of: In this case the first three octets of the subnet mask are both 255. This means that the first three octets of the IP address belong to the network number. Hence the network number location of this IP address is 192.168.1.x.

This is important because the router’s job is to move packets of data from one network to another. All devices on the network (or specifically on a network segment) share a common network number. For example, if 192.168.1.x is the network number associated with the computers connected to the router in Figure B, the IP addresses for the four tablets could be:


As you can see, every computer on your local network shares the same network address, and the device number is different. When a computer needs to communicate with another computer, it does so by referring to that computer’s IP address. For example, in this particular case, the computer at can easily send data packets to the computer at since both of these machines are part of the same physical network. physical.

If one machine needs to access a machine on another network then things are a little different. Suppose that one of the users on the local network wants to visit website, a website on a server. Like any other computer, each Web server has a unique IP address. The IP address for this website is

You can easily see that the website’s IP address is not on the 192.168.1.x. In this case, the computer trying to reach the website cannot send the data packet out through the local network, because the Web server is not part of the local network. Instead, the computer that is sending the data packet will consider the default gateway address.

The default gateway is part of the TCP / IP configuration on a computer. It is a basic way of telling the computer that if you don’t know where to send the packet, send it to the specified default gateway address. The default gateway’s address is the IP address of a router. In this case, the selected router’s IP address is

Note that the router’s IP address shares the same network address as the other computers on the local network. The reason is so that it can access computers on the same network. Each router has at least two IP addresses. One uses the same network address for the local network, and the other is specified by your ISP. This IP address uses the same ISP network address. The router’s job is then to move the data packets from the local network to the ISP network. Your ISP has its own routers that work in the same way as any other router, but route the packets to other parts of the Internet.

When do you need a router?


Technically, if you only want to connect to the Internet for one device, you just need to use a modem. Although for security and flexibility reasons, it’s best to use a router even if there is only one device on your network.

But when it is necessary to provide Internet for many devices such as mobile phones, smart TVs, the router is an indispensable device. Remember the example of street names and house numbers. If there is only one house on one street, you don’t need a house number because it only has one location. But when there are many houses on that street, you need a specific address.

Users need a router not only to connect to multiple network devices, but also to connect multiple devices together. If you don’t have Internet, you can still create a local area network for computers and other devices. This allows you to transfer and share files with specific devices on a network like printers, scanners and game consoles .

  • Transfer data between computers

Router connects multiple devices

Without the router, data won’t be sent to the correct device. The document print job becomes useless when it is sent to the smartphone or the Google Home speaker instead of the printer.

Speaking of Google Home, the router is even more essential if you need to connect to your Smart home . Because Smart home is also a local network of devices, without a router they cannot communicate with each other. You can still use your local network without the Internet or a modem, but you can’t without a router.

What is the difference between a wired and a wireless router?


The difference between a wired router and a wireless router is the type of connection each device uses. Wired routers have only LAN cable ports while wireless routers (also known as WiFi routers ) have wireless antennas and adapters, allowing devices to connect without cables. Most routers and modems these days have LAN ports and antennas. There are a few things you need to keep in mind when choosing a Wi-Fi router to make sure you choose the right one.

As you can see, the router is an extremely important network component. Without routers, connectivity between networks (such as the Internet) would not be possible.

What is the business router that is so expensive?


Let’s take a look at the basic functionality of a router used in businesses and large organizations below you will understand why:

  • The business router usually takes the form of a device with integrated services, for example, in addition to providing network services, there are also applications and security.
  • Integrated hardware-based VPN for remote access by customers and employees.
  • Highly configurable, providing advanced options for managing connected devices, such as quality of service (QoS) control for specific devices, ports and traffic types.
  • High-end business routers, such as routers developed by Cisco, will require separate devices to create wireless access points and will use external switches to connect the wired device to the router.
  • Business routers typically use high-quality components that have been performing consistently for many years.

As you can see, the business router is more complex, and it also cuts off some of the features that a home router has. Business routers are designed to be the only high-performance device in a larger and more complex network, while home routers are designed to be an all-in-one solution, easy to connect and access. .

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