Let us look at the internet from a height of 50000 feet. Again, don’t be concerned about all the networking jargon. Simply keep them in the back of your mind.
A network is a collection of computers and other devices that can send and receive data in real-time from one another. A network is often connected by wires, and bits of data are converted into electromagnetic waves that travel through the wires. Wireless networks, on the other hand, use radio waves to transmit data, and most long-distance transmissions are now carried over fiber-optic cables, which send light waves through glass filaments.
Each machine on a network is referred to as a node. Printers, routers, bridges, gateways, dumb terminals, and Coca-Cola machines are examples of nodes. You’ll mostly interact with other computers. Hosts are nodes that are fully functional computers. We will use the term node to refer to any network device, and host to refer to a node that is a general-purpose computer.
When two computers need to communicate, they must be linked either physically (via an Ethernet cable) or wirelessly (for example with Wi-Fi or Bluetooth systems). Any of those connections can be sustained by any modern computer.
There is nothing sacred about any physical medium for data transmission. In theory, data could be transmitted by coal-powered computers that communicate via smoke signals. Such a network’s response time (and environmental impact) would be quite poor.
Note: For the remainder of this article, we will only discuss physical cables, but wireless networks function similarly.
Just plug in that cable, and the network is up and running, right? Network cables work quietly, moving data from one location to another faster than we can blink.
Before we continue, one more thing should be mentioned. Computer networking refers to the interconnection of computing devices that can exchange data and share resources. To transmit information over physical or wireless technologies, these networked devices employ a set of rules known as communications protocols.
Writing computer programs that allow processes to communicate with one another across a computer network is what computer network programming implies.
The majority of computer network programming takes place at the Application Layer (will discuss later). We will use Java as the programming language to create a networking program to demonstrate a concept(if the need arises).
We’ll start with the terms you’re most familiar with. Then we’ll get into the less familiar terms.
How Does The Router Work?
The router’s actual function will be discussed later. We’ll talk about routers in this section because they’re probably the most familiar networking device to you. And we’ll talk about routers in a way that makes sense to you at this point.
A network does not have to be limited to two computers. You are free to connect as many computers as you want. However, things quickly become complicated. If you want to connect ten computers, you’ll need 45 cables, each with nine plugs!
To solve this issue, each computer on a network is linked to a special tiny computer known as a router. Consider a router to be an air traffic controller, and messages to be aircraft flying to various airports (or networks). Each message, like each plane, has a unique destination and must be guided to its destination as efficiently as possible. A router helps direct messages to their destination in the same way that an air traffic controller ensures that planes arrive at their destinations without getting lost or experiencing major disruptions along the way.
Once we add a router to the system, our network of ten computers requires only ten cables: one for each computer and a router with ten plugs.
How Does The Modem Work?
What about connecting hundreds of thousands, if not billions, of computers? Of course, a single router cannot scale that far, but remember that we said a router is a computer just like any other, so what’s stopping us from connecting two routers together? Nothing, so let’s get started.
We can scale infinitely by connecting computers to routers, then routers to routers.
This network is very close to what we call the Internet, but something is missing. That network was built for our own purposes. Other networks exist your friends, your neighbors, anyone can have their own computer network. But setting up cables between your house and the rest of the world isn’t really an option, so how do you deal with this? There are already cables connected to your house, such as power and telephone. Because the telephone infrastructure already connects your home to anyone in the world, it is the ideal wire we require. A modem is a special piece of equipment that we need to connect our network to the telephone infrastructure. This modem converts information from our network into information that the telephone infrastructure can handle, and vice versa.
Now, we are connected to the telephone infrastructure. The next step is to send messages from our network to the network we wish to communicate with. To accomplish this, we will link our network to an Internet Service Provider (ISP). An ISP is a company that manages a network of special routers that are all connected together and can also access the routers of other ISPs. As a result, the message from our network is routed to the destination network via the network of ISP networks. The Internet is made up of this entire network infrastructure.
The Network Media
The communication channels used to connect nodes on a computer network are referred to as network media. Copper coaxial cable, copper twisted pair cables, and optical fiber cables are common examples of network media in wired networks, and radio waves are common examples in wireless data communications networks. As aforementioned, this course will only cover wired network media.
