Greetings Fellow Reader!
A Very Warm Welcome to you at my Blog. Networking is a very vast topic and therefore segmented into various Categories which further have their subcategories. I am going to cover some important topics like "The Internet", "Social Media Networking", "Internet Protocols(IP)" and various concepts of "CYBER SECURITY". So Buckle up! and get ready to explore the wonders of Networking.
First of all,I am going to start by describing the Backbone of Networking-"The Layers".
These layers aren't any physical Entity rather of Logical significance. When the concept of layers came, all the possible layers that were required for establishing a Network were defined(As we see in the OSI Model). But gradually we realized that some of the layers could've been eliminated without degrading the performance of the Network. This was the TCP/IP Model. We'll look into both one by one:
First of all,I am going to start by describing the Backbone of Networking-"The Layers".
These layers aren't any physical Entity rather of Logical significance. When the concept of layers came, all the possible layers that were required for establishing a Network were defined(As we see in the OSI Model). But gradually we realized that some of the layers could've been eliminated without degrading the performance of the Network. This was the TCP/IP Model. We'll look into both one by one:
Starting off with The OSI Reference Model:
The Open System Interconnection model was the first ever reference model that explained Network as a step-by-step layered process.It was proposed by The International Standards Organization. When this idea of one Host being able to communicate with another Host came up, it was of coarse revolutionary. Every IT Company wanted their versions of computer(with their own operating system) to have this very ability to communicate with each other,to be able to share data of all sorts(in any format).
This was made possible by developing a Standard Network Card which would take the data through these particular layers. This Card would then be embedded inside their Computers.
Each layer could be thought of as a level. Each level has certain rules or constraints and on satisfying all of these rules the data gets promoted to the next level.
Let us look into these levels:-
We'll start with the bottom most layer and gradually go up. First of all we have the Physical Layer.
For Better understanding these layers of Networking, let us take the analogy of Postal Mail Service.
We'll start with the bottom most layer and gradually go up. First of all we have the Physical Layer.
For Better understanding these layers of Networking, let us take the analogy of Postal Mail Service.
Physical Layer:
After we finish writing the letter the next thing that we do is drop the letter into the mailbox. This is the first process: "To place the data into the Postal Mail system." Similarly we put our Ethernet cable into the port(if wired) or place our device inside the range of WiFi (if Wireless).
This implies that as soon as we plug in our Ethernet cable into the port or get a "WiFi available" signal(without logging in the password) on our devices, we have already started transferring data between the two!!
The data handled in this layer is the primary(simplest) form of raw data. It is simply in the form of 0's and 1's. Thus data in this layer is called Bits(Binary Digits).
Next up is Data Link Layer...
Data Link Layer:
After the mail is picked by the Postman/woman, he/she checks out the Physical State of the letter - If the letter is stamped and in proper condition to be transported further. This is what Data link Layer does. It Checks whether the group of Binary digits coming from the physical layer is error free and does not have any contents possessing any Potential Threats.
Networking Layer:
If nothing is wrong with the envelop so far, the next thing the postman does is to check the address of the receiver and that it's sender has a legitimate address. In Networking this envelop is termed as a Packet(Data in Network Layer) and the relevant information about the packet is stored in a Header file. This Header file is attached with the Packet itself.
Also if the postman/woman finds that the letter is addressed to Tony Stark,the Iron man ...that letter is dropped! Similarly this layer of Networking looks at the address of the receiver. This address is none other than the "IP Address"(Internet Protocol). There is still a lot more in IP Address. We'll look deeper into it in the upcoming articles. But for now, we can fairly say that this process of dropping the packet if it's IP Address is invalid is known as Request -Timeout.
Transport Layer:
If till now everything is fine, the Mail person sends the letter through a particular medium(Roadways,Railways,Seaways or Airways). Similarly if the data is successfully arrived to Transport Layer from the Network Layer, the port address is checked. The port address is a number which tells the process by which the packet is going to be sent further(HTTP , FTP etc.). We'll look further into Port numbers in our upcoming articles.
Session Layer:
If the receiver doesn't get the letter for a couple of days, he/she verifies the status of the letter from various Post Offices. If there is some suspicious delay in the letter delivery,he/she drops a query. Similarly, if there is a longer delay in delivery of the packet, the Receiving PC automatically sends a query to the Sender's PC just to check if there is something wrong within the Network or not. We do not realize it. This automatic sending of Request by our Host is known as Automatic Request Query (ARQ) development.
Presentation Layer:
Next if the receiver gets the letter and finds out that the language of the letter is that of some Extra-Terrestrial Society, there is no point of all these letters...init!
Similarly if on finding the complete data, you find that the format/type of data is incompatible with your PC...everything will go wrong. To prevent this from happening ,presentation layer is present. This layer checks whether the file is a .exe, .mp3 , .wav etc.
Application Layer:
Once the letter is reached to the receiver and is readable by him/her. Well he/she reads it...
Similarly if the receiver's host gets the data without any problems,he/she executes it.
This completes all the layers of Networking. Look at these few points as a Bonus:-
- Let's Assume that the client is the sender and that the server is the receiver. This is not a straightway connection. There are several intermediate servers through which the data is passed. The data isn't shared with all of these intermediate servers. Only the relevant addresses. Thus these servers have access only till the Network Layer. This is due to the following reasons:
- Security
- Unnecessary- Our soulful purpose is to send the data to the ultimate server. We don't bother about the intermediate servers. This is what is depicted in the diagram below:
This was the OSI reference Model. Then came the "TCP/IP "Model. TCP/IP model had fewer layers. The Application Layer had Session and Presentation Layer properties inside it.
The Network layer was named as the IP Layer and the Data Link Layer was combined with the Physical Layer.
This completes our tour on the "Layers of Networking". I hope you like it. This blog is still under Progress. But hang in there cause more amazing articles are on their way.
Thanks for reading.Do share your comments about this blog or if you have any queries of any sorts.
