Ported all networking blogs

_posts/2017-08-01-NFC-Explained-In-2-Minutes.md

@@ -0,0 +1,30 @@
+---
+layout: post
+title: NFC Explained In 2 Minutes !!
+tags: networking
+description: Basics Of NFC
+---
+
+-- [Rohit Bhaskar ](https://www.linkedin.com/in/rohitb1vs10/)
+
+![](/assets/posts/NFC-Explained-In-2-Minutes/images.webp)
+
+Hi guys! I know its been a reeeeeally long time and I apologise for it, but as they say, ‘life is what happens to you when you’re busy doing other things‘. So, let’s get to the point without further ado 🙂
+
+A huge majority of us have probably either used **NFC (Near Field Communication)** or have seen it in action (or have at least heard about it…hopefully. If you haven’t then you need to get out of your cave ASAP). If you’ve heard of Apple Pay or Samsung Pay, all these use NFC. NFC has been with us for quite a while now. To put it simply, NFC is just a wireless communication method…that’s it. No magic here, sorry 🙂
+
+```How it works is that a NFC chip operates as one part of a wireless link. Once it’s activated by another chip, small amounts of data between the two devices can be transferred when held a few centimeters from each other.```
+
+So what’s so special about it that all the big companies are trying to incorporate it? And anyway we already have WiFi and Bluetooth right? So what does NFC bring to the table? The answer to this is mainly 2 things:
+
+1. Much lesser power required
+2. Faster connectivity
+It requires  lesser power since it can work as a passive device (without having a power source). This is since it’s based on RFID (Radio-frequency identification) tech, which uses electromagnetic induction.
+
+Coming to faster connectivity. Due to the use of inductive coupling, and the absence of manual pairing, it takes less than one tenth of a second to establish a connection between two devices.
+But as every other technology, it also has it’s drawbacks. NFC only has a range of around 10cm, that’s just a few inches!! Another drawback is that NFC is quite a bit slower than its competitiors like bluetooth, transmitting data at a maximum speed of just 424 kbit/s.
+
+Looking toward the future, it’s possible that NFC chips could be used to replace every card in your wallet!
+ But the potential for NFC stretches further than commerce. Passive NFC ‘tags’ are being built into posters and informational kiosks to transmit additional information similar to how scanning a QR code can trigger launching a web address, offering a discount coupon, or a map to download on your smartphone.
+That’s all for this post!! And here’s a list of compatible devices, if you’re really interested in trying 🙂
+

_posts/2017-08-15-GSM-Explained-In-2-Minutes-!!.md

@@ -0,0 +1,29 @@
+---
+layout: post
+title: GSM Explained In 2 Minutes !!
+tags: networking
+description: Understanding GSM Technology
+---
+
+-- [Yash Hule](https://www.linkedin.com/in/yash-hule-33784612b/)
+
+![](/assets/posts/GSM-Explained-In-2-Minutes-!!/logotipo_GSM.png)
+
+GSM technology is the technology that you (most probably) and 80% of mobile users use for making calls on their mobile phones. In a way, it is the standard and default wireless protocol used for mobile communication.
+
+GSM started back in 1982 and was then named after the group that devised it, Groupe Spécial Mobile, whence the GSM acronym. The official protocol was launched itself in Finland in 1991. It is now called **Global Systems for Mobile communications**.
+
+
+GSM is considered a 2G (second generation) protocol. It works with cells, which is why a GSM network is also called a cellular network, and phones working on GSM are called cell phones. Now what is a cell? A GSM network is split into cells, each one of which covers a small area. Devices (phones) are then located and communicated with through these cells .A GSM network consists mainly of connection devices (gateways etc.), repeaters or relays, which people commonly call antennas – these massive metal structures that stand as high towers and the mobile phones of users. The GSM or cellular network is also a platform for 3G communication, which carries data over the existing network for Internet connectivity. GSM system was developed as a digital system using time division multiple access (TDMA) technique for communication purpose. A GSM digitizes and reduces the data, then sends it down through a channel with two different streams of client data, each in its own particular time slot. 
+
+![](/assets/posts/GSM-Explained-In-2-Minutes-!!/Gsm_network_architecture.png)
+
+Dont worry if you didnt understand. Look below for a more simple approach to understanding the concept :)
+
+
+# GSM Simplified
+
+Let’s look at the above in a day to day life example, consider the postal service. We want to send a letter, so we post the letter with the receiver address details and drop in mail box the postman picks it up and drop at the nearest Post Office. The office is filled with many such letter their the letters are segregated and our letter is transported to   nearby post office of the receiver location. At the receiver end the letter is given to a postman to deliver the letter to particular address thus the letter get dropped in receiver’s mail box.Let’s get into technical aspect of things the letter we want to send is actually a call we want to place using our phone the  postman is acting as a mobile tower to send the call from sender end to a base station where it is being segregated to put  on same frequency band as that of a receiver and from base station it is sent through optical cables to the network station over to receiver’s location their it is checked to be sent to the correct person in that region our call again send through signals to the tower from that to the receiver in his home. This steps occur during every call we place in a jiffy so that we actually never realize the delay.
+
+This is a 2 minutes explanation of GSM calling. Hope you understood the post :)
+

_posts/2017-09-02-LiFi-Explained-in-2-Minutes.md

@@ -0,0 +1,78 @@
+---
+layout: post
+title: LiFi Explained in 2 Minutes
+tags: networking
+description: Understanding the working of LiFi
+---
+
+-- [Rajneesh Katkam](https://www.linkedin.com/in/rajneesh-katkam-460204115/)
+
+![](/assets/posts/LiFi-Explained-in-2-Minutes/Lifi-image.jpg)
+
+
+Every imagined yourself returning home after a tedious work day (maybe from office or after attending 6-7 hours lectures in college, assignment submissions, labs and what not…) and then switching on your room’s light and Boom!! You get connected to an extremely high speed internet connection. (no, we aren’t talking about magic ;P)
+
+Think of yourself using an internet connection, which is 100x times faster than what the existing Wi-Fi system offers (I hope that you must have used Wi-Fi at your home/office/college or at least at your friend’s house) 
+
+
+... Umm… seems impossible....right? 
+
+
+**No**! It’s definitely possible and the technology that turns this into reality is Li-Fi (Light Fidelity).**The term Li-Fi refers to light based communications technology that delivers a high-speed, bidirectional, networked and mobile communications in a similar manner as Wi-Fi**.
+
+
+Prof. Harald Haas, coined the term "Li-Fi" at his 2011 TED Global Talk where he introduced the idea of "Wireless data from every light". Li-Fi uses visible light to transmit signals wirelessly and is an emerging technology poised to compete with Wi-Fi. It is 100x times faster than the Wi-Fi (mentioned it twice because even I didn’t believe it at first). 
+
+
+# So How Does Li-Fi Work? 
+
+![](/assets/posts/LiFi-Explained-in-2-Minutes/how-lifi-works-1024x576.png)
+
+Li-Fi is a Visible Light Communications (VLC) system for data transmission. A simple VLC system has two main components: 
+
+At least one device with a photodiode (photo detector) which is able to receive light signals.
+
+A light source equipped with a signal processing unit (Lamp Driver).
+
+A VLC light source could comprise of a fluorescent or light emitting diode (LED) bulb. Since a robust Li-Fi system requires extremely high rates of light output, LED bulbs are most ideal for implementing Li-Fi. LED is a semiconductor light source, which implies that LED light bulbs can amplify light intensity and switch on/off rapidly. Therefore, LED cells can modulate thousands of signals per second without the human eye ever noticing. In turn, the changes in light intensity from the LED light source are interpreted and converted as electrical current by the receiving photodiode device. Once the electronic signal is demodulated, it is converted into a continuous stream of binary data comprising of audio, video, web, and application information to be consumed by any Internet-enabled device.
+
+You can find video of its working  below. (Do watch it…)
+
+<iframe width="560" height="315" src="https://www.youtube.com/embed/25_dIc_4JG0" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
+
+# What’s the difference between Li-Fi and Wi-Fi?
+
+So the basic difference lies in the way the data is being transmitted. To be technical, Wi-Fi uses the Radio wave bandwidth of the electromagnetic spectrum whereas Li-Fi uses the visible wave bandwidth of the electromagnetic spectrum to transfer data. The frequency range for Radio wave is 3kHz - 300 GHz and for the visible light it is 400 THz - 800 THz. The frequency spectrum of these two waves reveal the fact that visible light frequency (in THz) is 1000 times more than the radio wave frequency (in GHz) and hence the reason to achieve high speed data transmission rates.
+
+The transmission of data in case of Li-Fi is done through rapid switching on/off of LEDs i.e. changing the intensity of light (human eye cannot see the rapid switching phenomenon), whereas in case of Wi-Fi, the data is transmitted via modulation of data signals on to radio signals and then demodulating it at the receiver’s end.
+
+
+## Advantages of Li-Fi technology:
+
+    • Efficiency: Li-Fi works on visible light technology. Since homes and offices already have LED bulbs for lighting purposes, the same source of light can be used to transmit data. Hence, it is very efficient in terms of costs as well as energy. Light must be on to transmit data, so when there is no need for light, it can be reduced to a point where it appears off to human eye, but is actually still on and working.
+
+    • Availability: Wherever there is a light source, there can be Internet. Light bulbs are present everywhere – in homes, offices, shops, malls and even planes, meaning that high-speed data transmission could be available everywhere.
+
+    • Security: One main advantage of Li-Fi is security. Since light cannot pass through opaque structures, Li-Fi Internet is available only to the users within a room and cannot be breached by users in other rooms or buildings. (So, now you won’t have to share password with your friends. @@)
+
+
+## Disadvantages of Li-Fi technology:
+
+    • Internet cannot be used without a light source. This could limit the locations and situations in which Li-Fi could be used.
+
+    • Because it uses visible light, and light cannot penetrate walls, the signal's range is limited by physical barriers.
+
+    • Other sources of light may interfere with the signal. One of the biggest potential drawbacks is the interception of signals outdoors. Sunlight will interfere the signals, resulting in interrupted Internet.
+
+    • A whole new infrastructure for Li-Fi would need to be constructed.
+
+
+But it's not all doom and gloom! Due to its impressive speeds, Li-Fi could make a huge impact on the internet of things too, with data transferred at much higher levels with even more devices able to connect to one another.
+
+Recent experiments carried out have showed impressive results of achieving 100 Gbps with laser LEDs. 
+
+The Li-Fi products are already out in the market. You can [find more information about Li-Fi technology and its products online](https://purelifi.com/).
+
+I know it was reeeally long post, but that’s all for today!! Hope you understood what LiFi is :)
+
+

_posts/2017-12-09-Optical-Fibres-Explained-In-2-Minutes.md

@@ -0,0 +1,36 @@
+---
+layout: post
+title: Optical Fibres Explained In 2 Minutes
+tags: networking
+description: This blog is an introduction to optical fibres
+---
+
+-- [Yash Hule](https://www.linkedin.com/in/yash-hule-33784612b/)
+
+![](/assets/posts/Optical-Fibres-Explained-In-2-Minutes/2017-12-09-Optical-Fibres-Explained-In-2-Minutes.jpg)
+
+Ever thought that light can be used to carry messages and for communications between two or more devices ? Did you know the internet which you get you comes in the form of light ? How’s this possible? 
+
+Ans. **Optical Fibre!!**
+
+This post is going to be extremely interesting for communication engineers! :)  So let's begin
+
+Over the last 20 years or so, fiber optic lines have taken over and transformed the long distance telephone industry. Optical fibers are also a huge part of making the Internet available around the world. When fiber replaces copper for long distance calls and Internet traffic, it dramatically lowers costs. 
+
+An optical fibre is a flexible, transparent fiber made by drawing glass (silica) or plastic to a diameter slightly thicker than that of a human hair. Unlike copper wire based transmission where the transmission entirely depends on electrical signals passing through the cable, the fiber optics transmission involves transmission of signals in the form of light from one point to the other. Furthermore, a fiber optic communication network consists of transmitting and receiving circuitry, a light source and detector devices like the ones shown in the figure below.
+
+When the input data, in the form of electrical signals, is given to the transmitter circuitry, it converts them into light signal with the help of a light source. This source is an LED or a laser whose amplitude, frequency and phases must remain stable and free from fluctuation in order to have efficient transmission. The light beam from the source is carried by a fiber optic cable to the destination circuitry wherein the information is transmitted back to the electrical signal by a receiver circuit.
+
+Working of Fiber optic communication:
+
+![](/assets/posts/Optical-Fibres-Explained-In-2-Minutes/working_of_fibres.jpg)
+
+The Receiver circuit consists of a photo detector along with an appropriate electronic circuit, which is capable of measuring magnitude, frequency and phase of the optic field. This type of communication uses the wavelengths near to the infrared band that are just above the visible range. Both LED and Laser can be used as light sources based on the application.
+
+**To understand in a simple way how a fiber optic cable works, imagine an immensely long drinking straw or flexible plastic pipe. For example, imagine a pipe that is several miles long. Now imagine that the inside surface of the pipe has been coated with a perfect mirror. Now imagine that you are looking into one end of the pipe. Several miles away at the other end, a friend turns on a flashlight and shines it into the pipe. Because the interior of the pipe is a perfect mirror, the flashlights light will reflect off the sides of the pipe (even though the pipe may curve and twist) and you will see it at the other end. If your friend were to turn the flashlight on and off in a morse code fashion, your friend could communicate with you through the pipe.**
+
+That is the essence of a fiber optic cable.
+
+This is a 2 minute explanation of how communication takes place by optical fibre. Optical fibre are also used for medical,defence and a lot more purposes.The advantage offer by this over other means is the large amount of data which can be sent over long distance more efficiently at faster rate reliably. The loss of information and distortion is negligible.
+
+Hope you understood!

_posts/2018-03-11-OSI-Model-Explained-In-2-Minutes.md

@@ -0,0 +1,59 @@
+---
+layout: post
+title: OSI Model Explained In 2 Minutes
+tags: networking
+description: This blog is an introduction to OSI Model
+---
+
+-- [Shubham Patil](https://www.linkedin.com/in/shubham-pravin-patil/?originalSubdomain=in)
+
+![](/assets/posts/OSI-Model-Explained-In-2-Minutes/osi-model-fb.jpg)
+
+ello everyone! in my debut post on the SRA blog, I'll be giving you a simplified explanation of the **OSI (Open System Interconnection) Model**:
+
+I'm pretty sure every engineer would have come across this term sometime during their 4 years. The OSI is an extremely popular communication standard.
+The OSI model defines standards for:
+• The way in which devices communicate between each other.
+• The means used to inform devices when to send data and when not to transmit data.
+• Methods to observe correct rate at which data flows.
+• Means by which we come to know that the data has reached to its respected recipient.
+
+# What is OSI Layer?
+OSI (Open Systems Interconnection) Reference Model since it describes or relates to connecting systems that are open for communication with other systems. In the model, the functions of the communication system are standardized by categorizing them into abstract layers. Each of the layers of the OSI model is intended to function with those above and below it respectfully within the model definition.
+
+# What Are the Seven Layers of the OSI Model?
+
+We always have problem remember things in sequence right no one remembers all the elements in Periodic table with their names hence we devise mnemonic for such things. A common mnemonic used to remember the OSI model layers starting with the seventh layer (Application) is: “All People Seem to Need Data Processing.”
+
+![](/assets/posts/OSI-Model-Explained-In-2-Minutes/osi-model.png)
+
+1. Application Layer:
+The Application layer provides the necessary services that support applications. It provides the interface for e-mail, Telnet and File Transfer Protocol (FTP) applications, and files transfers. It means that the its only job in simple terms is to take data input and output from and to user respectively.
+
+2. Presentation Layer:
+This layer deals with the format of the data when it being transferred so that other layers can also understand what kind of data is transmitted through network. When the data is received, the Presentation layer translates the data to a format which the application can read. Compression and Encryption {which we will take in another post :p} functions fall in this layer.
+3. Session:
+The best way to remember a session is thinking of it as a Hangout or WhatsApp messenger. When two people start communicating a session is created, as soon as one ends or disconnects video/audio call, session is broken. That means it is responsible for maintaining and ending communication between two receiving devices.
+4. Transport:
+This layer provides you with the best possible path for data transfer between two recipient. Also provides secure data transfer and error checking and recovery of data between two members.
+5. Network:
+This layer takes care of the ways data will be sent. The protocol used for sending data will also be decided here. Consider you are data the and you want to reach your college then your choice of transport here becomes the protocol. One main feature of network layer is Routing. Routing enables transport of packets among computers which can be linked to one or many others.
+6. Data Layer:
+The data link layer provides a reliable link between two directly connected nodes. It is
+responsible transmitting data over a link from one device to another, by providing interface
+through network medium to software medium.
+7. Physical Layer:
+This is the level of the actual hardware. Hardware such as the physical components of
+Ethernet cables and Bluetooth are just some examples of the physical layer. In this layer you
+will define the following :-
+
+    * *Defining physical specifications*
+
+    * *Defining protocols*
+
+    * *Defining transmission mode (half duplex & full duplex)*
+
+    * *Defining the network’s topology*
+
+
+So that concludes our post on the OSI model. It might have gotten too technical, but i hope you understood ;)