Imagine you send a text message to your friends about bunking a lecture and it gets delivered to your teacher... You will think this is absurd right? We don't see this in the real world. The Internet has become a reliable and secure way to send and receive texts and various other files but do you wonder how do I sitting in a weird position(in my defense, it makes me more productive) could deliver you such an interesting blog on networking?
The OGs Of The Internet
It's a classic story of rivalry, no Not CIA vs KGB but the country's scientists. USA and Russia both wanted to be the first to have a satellite in space...(Some crying noises)
Russia with Sputnik 1 was the first country to have a artificial satellite in space. So to not be at any other disadvantage in scientific research and wars, the US wanted a way to communicate between two computers to send research papers and deploy warfare systems.
Advance Research Project Agency
In short ARPA, it was the first organization to link computers and form the first form of Computer Network. The computers placed at MIT, UCLA, Stanford and UTAH were connected with wires to form ARPANET. At first, ARPANET had only 3 basic functionalities sending data between computers, printing and logging in remotely. It became testing grounds to further develop possibilities through networking.
"With Great Data Comes Greater Responsibilities"
Believe me, it's not copied... it's inspired. So here comes the devices which in real-time are transferring Terabytes of Data between two computers across localities, cities or countries.
Ways of Communication:-
Guided Communication: Also known as wired communication, where data is sent in the form of analog or light signals through wires.
Un-Guided Communication: As you have guessed Wireless communication, where data is sent in the form of radiowaves through antennas or network towers.
Networking Devices:-
Repeaters & Hubs: I bet you have encountered at least one Chatur (for folks who have not watched 3 Idiots(movie)... just watch it dude). As Chatur always just reads and pastes it, a repeater too has a similar job. As across a certain distance the analog signals get weaker, a repeater amplifies the signal and restores it to its original strength so that there is no data loss. So what are hubs? Since the repeater was a two-point device i.e. it could only connect two devices, hubs is a multi-port repeater thus giving us the ability to connect multiple devices.
Bridges & Switches: We have wires and hubs to connect and transfer the data, So just why another device? So the hubs are so dumb they will send the data which originally was meant for a specific device to every device that was connected. Obviously you don't want your message to be broadcasted to everyone, here comes Bridge. A Bridge uses Layer 2 Address so-called physical address of the network interface(basically the MAC address of your Wifi or Bluetooth hardware, we will look into details later) to route the data to the proper destination. As you guessed it Switches are Multi-port bridges.
Router or Modem: Till now we could send data within our network without worrying about data being sent to the wrong user, but what if the user you want to reach is on another network, simply over long distances. So every network has an ID called Net-ID which is a part of the IP Address, Net-ID is a unique combination of numbers that is used by the router to identify the network.
The application knows the IP address of your destination which is also referred to as Layer 3 address or Logical address, thus it also knows on which network your destination is. So the router will send data to the router of that network and then the router will give data to the switch which will deliver the data to the destination.
BUT we don't use repeaters or bridges normally, right? Yes because in small networks, the router does all of this for you.
Let's look into the Types of Network Architecture
Based on Hierarchy we have :-
Client-Server Architecture - It is a centralized structure, where the Server is the main computer that allocates resources to all the nodes i.e. clients connected to the network. For example, if a client wants to print something but doesn't have a printer but the network to which it is connected has one, the client will send a request to the Server to access the printer and if allowed it will print what the client desired.
Peer-To-Peer Architecture - A decentralized architecture where everyone could use every resource in the network. For example, Blockchain.
Based on the Scale we have :-
Local Area Networks (LANs) - It is only limited to an area like a school or office building, where every device is connected through ethernet cables. It has no limitations on number of devices that are connected. Smaller than this, there is Personal Area Network (PANs). We also have Wireless Local Area Network (WLAN).
Metropolitan Area Networks (MANs) - These networks range across cities, i.e. computers connected across cities using Coaxial cables or Optic Fibres. Smaller than this but larger than LANs we have, Campus Area Networks (CANs).
Wide Area Networks (WANs) - A network so distant that we laid underwater wires to communicate. These networks are generally across countries. We have optic fiber cables underneath oceans which carry our data at light speed.
Based on Topology we have :-
Bus Topology - All the nodes are connected to a single wire which works as a backbone of the network. Its limitations are: Only 1 person can communicate at a time & if the backbone is severed it shuts off the whole network.
Ring Topology - All the computers are connected in a ring structure. Its limitations are: To transfer data from one computer to the computer somewhere between the ring, your data hops from device to device thus its inefficient and security risks.
Star Topology - In this all the nodes are connected to the central device. It is efficient but if the central device fails the network shuts off.
Mesh Topology - In this network every computer is connected to every other computer. It is extremely reliable but costly as scaling this network costs a lot.
Tree Topology - It is a mix of Bus & Star topology and thus it carries limitations of both of these networks.
Based on Functionality we have :-
Storage Area Networks (SANs) - Nowadays, you can rent computing power on demand similarly you can have storage on demand which could be accessed from anywhere without human interference. E.g. Cloud Storage. These are different than Network Attached Storage (NAS) as NAS is only available within the network and to all the devices connected to it whereas SANs are available across the network and only to the authorized user.
Virtual Private Networks (VPNs) & Virtual Private Servers (VPS) - Want privacy? VPNs and VPS allows user to connect & communicate across the internet anonymously. Companies own Servers that allow users of these services to use these servers as a gateway to access the internet.
Now to leave you with a Question of the blog and what you could expect from the next blog, How does a computer know which app the received data belong to? If there are multiple tabs of a certain application, to which tab the data should be delivered? What are IP and MAC addresses?
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