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When talking about computer networking, it usually seems like a subject restricted to IT professionals.
However, they are present in almost everything that is part of the modern world and what we do on the Internet.
Thanks to them, in addition to browsing the websites, you can listen to music and watch streaming movies, make payments using your credit or debit card, use your GPS device or Google Maps, control the baby monitor via your smartphone or have the goods purchased on e-commerce separately in record time.
In fact, there are now larger home networks with more data traffic than many of the primitive enterprise computer networks of the past.
So, in today’s chat, we’re going to kick-start the subject and talk about the emergence of networks and what computer networks are.
History and emergence of computer networks
When talking about the history of computer networks, unlike some advents, it does not have a precise date or even a year of launch, but its evolution is understood over a period.
This is because when considering the events that would later give impetus to their actual emergence, computers did not even exist, at least not in the way we are used to imagining them.
The concept that would later be implemented was born in the 60’s when there was intense research for the development of technologies aimed at voice communication, which soon realized that they could also be used for data transmission, since voice networks used the concept of transmitting packets through electrical signals on wires.
But it was only in the 70s that the first networks appeared, although there was still no computer like we have in networks today.
The few mainframes – literally huge computers that could occupy an entire room – existing in large companies, governments and research centers, were accessed by terminals and which basically were a keyboard and a monitor.
Despite their particularities, these were the “embryos” of current networks.
At that moment, those involved understood that it was necessary to create a language for the machines to communicate with each other in a more secure and reliable way.
And for that, TCP/IP (Transmission Control Protocol / Internet Protocol) was used, which at the time was implemented by the US Department of Defense Advanced Research Projects Agencyfor the so-called ARPANET project, still in 1969 and which would later give rise to the Internet.
It is worth mentioning that initially the protocol used in the ARPANET was not TCP/IP, but the NCP (Network Control Protocol) and that it soon proved inadequate to manage a large volume of data that the growth of the network would demand.
In 1972, when the ARPANET was officially “launched”, it was already a network of 15 nodes, which are the data exchange points of a network.
Five years later, in 1977, there were already about 100 nodes, among which there were computers from the Pentagon, from research centers and universities, such as MIT (Massachusetts Institute of Technology), Harvard, Stanford and UCLA and even a few companies, such as to Xerox.
About a decade later, in the 1980s, computers began to become smaller and more affordable, thanks to the development of processors by companies such as Intel, IBM and Motorola, when the term PC (Personal Computer or Personal Computer) was coined.
It was the first, which appeared in the mid-70s, the 8086 and which served as a model of the famous x86 architecture used in many of the modern processors.
At the same time, the “popularization” of computers boosted the proliferation of PC communication networks and the Internet itself.
What is a computer network?
In the simplest and most simplistic answer possible, it is connecting two or more devices together so that they are able to exchange data and share resources.
Thus, a notebook correctly connected to a printer – either by WiFieither by USB cable – it is a network, very small indeed, but it is one, since they exchange information and in the case of the notebook, it uses the printing feature.
Note that the two conditions – exchanging data and sharing resources – do not necessarily need to be verified for network characterization. Just one.
Every computer network, no matter how simple in terms of devices, must have basic rules for communication to take place in order to guarantee the safe and efficient sending of data and this is called network protocols.
That’s why we mentioned just above that it’s a network when the notebook is correctly connected to the printer, without which, communication doesn’t happen and strictly speaking we can’t say that there is a configured network.
Just physically connecting two devices with a cable does not imply having a network, as this requires a series of protocols, rules and controls.
In other words, it is necessary for data to travel from one computer to another, without being altered or lost, and for that, the network must be able to determine exactly where the data comes from and where it goes, which implies that each interconnected device can be identified, which is possible thanks to the IP adress.
All these processes are the responsibility of the network.
What are the components of a network?
For a network to function as we have seen so far, it needs two groups of components – hardware and software.
In terms of hardware, we have both the devices that we use that are more obvious and well-known, such as the notebook and the smartphone, but there are also devices from the Internet of Things (IoT), such as IP cameras, refrigerators, autonomous vehicles, robots, smartwatches, smartTVs, game consoles and finally, those that are part of the infrastructure, such as servers, switches, routers, modems, firewalls, etc.
In the software group, just as we have the operational system and the various applications on the notebook or smartphone that interface with the hardware to deliver results, on a network there are also programs with a similar objective, either instituting protocols (TCP/IP, HTTP, SMTP, POPUDP, FTPetc), or by manipulating and combining them through a friendly interface, to perform actions, such as browsersemail clients and terminals (telnet, SSHetc).
Therefore, a network infrastructure is necessarily composed of hardware and software.
What is a network protocol?
A network protocol is a well-defined and rigid set of rules, as well as an orderly set of actions, according to which data traveling on the network is exchanged.
Many of these protocols we use daily on the internetsince it can be said that it is the interconnection of several networks on a global scale and that is why it is also called the World Wide Web.
As we anticipated, each device on a network needs to be identified and identifiable, which is why each time you connect to the Internet or company network, your notebook is assigned an IP address.
In fact, when doing it on a local network, as in WIFI router from your home, it makes use of two IPs, one within the scope of the LAN (Local Area Network) and the other of the WAN (Wide Area Network).
For anyone outside your home network, everyone in your household has the same IP (WAN scope), but internally your notebook has an IP (LAN scope), your wife’s smartphone has another IP, the wireless printer has a third, and so on for each device connected to the router.
This assignment of which IP is assigned to each device is the responsibility of DHCP (Dynamic Host Configuration Protocol) and therefore a protocol.
When you open the browser and access any website, the rules that determine how the communication between the web server where the website is hosted and the browser takes place are determined by the HTTP (Hypertext Transfer Protocol).
Actually, the common, the correct and safe, is the HTTPS and no longer HTTP and which is nothing more than the latter with a layer of security through cryptography.
To send and receive emails, to upload your files to the cloud or to play online games, SMTP, POP2, FTP, TCP and UDP are used respectively. All examples are protocols that determine how data is controlled and transmitted for each situation and according to its nature.
So, for example, briefly when sending a email using SMTP, the two mail servers start with HELO/EHLO and what is also known as “hand shake”, where both servers identify themselves by telling each other their respective nameservers, confirm the SMTP or ESMTP (Extended SMTP), sender, recipient, message size, transmission of data relating to its content and end with the QUIT command.
This sequence of actions and how each piece of information is transmitted is the email sending protocol (SMTP or Simple Mail Transfer Protocol).
What is the basic structure of a network?
It can be said that the structure of a network is composed of the edge of the network, the core and the links.
The edge of the network corresponds to the final or outermost portion of the devices. In the case of the core, in general, it is characterized by routers, but it can also be a server, in the case of a VPN or even one firewall. Finally, the links are the means to connect everything and that can be a cable or radio waves in the case of 5G or give starlink.
When through your notebook you connect using a cable directly connected to the router to access websites on the Internet, we have:
- The servers on which the websites accessed are hosted, as well as your notebook, are elements of the network edge;
- The router, the access provider’s modem, routers and switches within the provider’s infrastructure and the same in the data center which the server that hosts the website is on, are part of the core of the network;
- Finally, the cable that connects the notebook to the router, which goes from your home to the pole and from the pole to the access provider, as well as all the other cables to the data center, are the links.
Conclusion
Computer network is the hardware and software infrastructure for exchanging data between two or more devices and is the basis of everything we have on the Internet.
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