Ethernet[What Is Ethernet]

Ethernet:

Ethernet Connection Cable

Ethernet is a LAN technology with which we can connect many computers together and transfer data between them. To build ethernet connection we use mainly 3types of ethernet cables which are:

1. Coaxial Cable

2. Twisted Pair Cable

3. Optic Fibre Cable

Coaxial Cable:

It is a signal wire. It made with an insulator, metallic shield and plastic. In this cable, insulator controls the signal of our data. Metallic shield controlled electromagnetic interference. And plastic prevents the wire from water and other external strikes.

Twisted Pair Cable:

This cable basically made with 2 or 4 copper wire. To prevent cross talk it patches each other.

Fibre Optic Cable:

Fibre optic cable is totally different from coaxial cable and twisted pair cable. Mainly it transfers data through light. Therefore it's speed is higher than coaxial and twisted pair cable.

In 1970 ethernet was first developed by engineers at Xerox Parc(a Xerox company) in California. After that Ethernet replaced with large LAN technologies such as ARCNET, FDDI and Token ring. When we talk about this kind of large LAN technology. Let's know a little bit of these.

The Token ring is a communication protocol for local area network. There is a three-byte frame which is called as "token" which moves around a "ring". ARCNET is known as Attached Resource Computer Network. It is also a communication protocol like Token ring. And FDDI which is known as Fibre Distributed Data Interface is a data transmission network connection. First, it was built with optical fibre but later with copper cable. That is why it is also called as Copper Distributed Data Interface. The ethernet is divide by many short pieces which is known as frames. These frames are the main part of the ethernet. Basically, it checks the error and checks the destination addresses. Here a new concept comes, which is the MAC address. The Media Access Control(MAC) address also checks the data packet along with the error.                                                                                                                                             

 If two devices try to transfer data between them at the same time then data packets face problem to connect with its destiny. To solve this kind of problem, the IEEE(Institute Of Electrical And Electronics Engineers) developed the Carrier Sense Multiple Access with Collision Detection(CSMA/CD) protocol, which allows devices to check that kind of data transferring problem. So, we can say that Ethernet is a standard type of protocol used to connect devices.

How Ethernet Works:

Think with an example that, you have a router. And you have connected all your smart devices together like computer, printer and others. Now when you give a command to your printer to print something then the data command goes into the router and then router send this message to the printer. In the past 30 years, ago there was a fixed coaxial cable which connects this all devices with a single cable. That time if a computer wants to send any data then it had to shout in the network to stop other devices.When other devices stopped then the process starts. If those two devices send that at the same time, then the communication starts with them. But there was a problem with this method. Because if more than two devices send data at the same time, then the ethernet cannot work. To solve this problem MAC or Media Access Control Address concept comes. Every network device has a unique number which is MAC. With this MAC address, every network devices got a globally unique name. Thus the problem solved. Now when we send any data the MAC address goes into the router and then the router sends its prefixed MAC address to another device. Thus the Ethernet works.

What Is Cache Memory

Cache Memory:

We know that CPUs are faster than memories. Day by day engineers are doing a lot of hardworking to make the chip smallest. They inputting more and more circuits on a single chip and thus they make a CPU so faster. As well as memory designers are also using various of technology to increase the memory capacity but they are not able to make its speed. Actually, the problem is not technology. The engineers are trying to build a memory which will as fast as CPU. But here a problem comes. If we want a high-speed memory then we have to locate it on the CPU and this is not an impossible task. But to locate it on CPU the total size will highly increase. To solve this kind of problem engineers are combining a small amount of fast memory with a large amount of slow memory. And we want huge facilities at a reliable price. And here the concept of cache memory comes. Basically, there are three types of memory is our computer. These are Hard drive, RAM and cache memory.

Cache comes from the French word cacher which means to hide. We can say that cache memory is a storage memory which can store top uses computer programs with a higher speed. It is a volatile memory. It is the fastest memory portion in a computer. But its storing capacity is very low respect to others memory. There are three types of cache memory:

1.   Level 1(L1) cache or Primary cache.

2.   Level 2(L2) or Secondary cache. 

3.   Level 3(L3) or Main Memory.

1. Level 1 or Primary Cache:

 L1 is the fastest cache memory which stays inside the processor. But it is very small than other cache memory. The storing capacity of L1 cache is between 2KB to 64 KB.

2.  Level 2 or Secondary Cache:

 L2 cache can stay inside the processers or others IC chips in processor. But where they stay is not a great matter because these chips are connected by a bus and it is quite fast to process. The storing capacity is between 256KB to 512KB.

3.  Level 3 or Main Memory:

L3 cache is the separate memory which speed is much more than a RAM. And its storing capacity is between 1MB to 8 MB.

How Cache Memory Works:

Basically, cache memory stores our daily important data command. When we give a command to the processor then it gets so many commands and to read or write any data. Here cache memory takes a major role. It stores our frequently used data which we need almost every time to operate the computer. Now when we give a command to computer then it will not go to RAM. First, it will check the cache memory and will take the instruction to process. Otherwise, it will go to RAM to pick up the instruction. So thus cache memory helps the processor to work fast. But sometimes when we give a command to the computer and it fails to find the instruction on the cache memory then again it goes to RAM to find that instruction. In that time the processor does delay which is known as cache latency. Thus cache memory works.

Working Of Cache Memory



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Protocol-What Is Protocol

Protocol

A protocol is a set of rules which determines how the data will be transmitted over in the network. Protocol are stored in binary information. It is a mixture of bits, characters, and integers.

Suppose there are 2 machines and we need to transfer some data to another machine. In this case of data transfer, there are some rules, which are known to us as Protocol. So, we can say that in networking protocol is a set of instructions that define how data will be transferred and how devices will communicate with each other. It is a communication standard which helps to communicate two devices. There are 3 levels in a protocol. These are:

1.  Hardware Device Level

2.  Software Level

3.  Application Level

And there are 2 types of protocol:

1. Standard Protocol:

Standard protocol helps to communicate multi winder means products of a different company.FTP,DNS,DHCP,SMTP,Telnet,TFTP are the standard protocol which are available for public users.

2.  Proprietary Protocol:

A proprietary protocol cannot support multi winder. It can support only company own devices. This is not available publicly. If anyone wishes to use that proprietary protocol, then he/she have to take permission of that protocol company means by which the protocol was created. Let's talk about IMessage which has made by Apple. If there are two Apple devices then by the proprietary protocol the communication could be possible. But in the case of other company devices, it will not be possible.

What Is Encryption

Encryption

Encryption

The internet is an open public system. We send and receive information over the internet connection. But even we know it is an open public system, we still exchange a lot of private data through the internet. We send very sensitive things like bank information, credit card number,cvv, password, emails, and others. So now, here it is a big question that, how do we keep this private stuff safe.

Encryption is a process to keep any kind of data safe. Scrambling a message to hide the original is encryption. And decryption is the process to unscrambling the message to make that readable.

This is a very simple idea in encryption and decryption and we have been doing it for a very long time. One of the first well-known methods of encryption was CAESAR'S CIPHER which was made after Julius Caesar. Julius Caesar was a Roman general who keeps encrypted his military commands by his enemies.

Caesar Cipher was an algorithm, that subtracts each letter from the original message with a letter of a certain number of steps down to the alphabet. In this case, when sender and receiver know that number then it called a key. To decrypt the message it will do to reverse the number.

But there was a big problem with Caesar Cipher. As Caesar Cipher was a method of number increase and decrease that is why it was very easy to crack the encrypted message by trying every possible letter and there, in the English alphabet, there are 26 letters which means you only need to try almost 26 keys to decrypt the encrypted message. Therefore a new method came. In Caesar Cipher we tried to encrypt the message by using only a fix number. Let imagine the encrypt message is "Hello".So here by using a key of 5, the message will be "Mjqqt".Now to make this difficult we will add a different amount of number key to decrypt. If we consider using 10 digit encryption, there could be 10 billion possible key solutions. That will be very difficult for us even it could take many centuries. But with a computer, it will take only a few seconds to decrypt the encrypted message. Thereafter encryption with 128/192 and 256-bit encryption came in market. Today's secure communications are encrypted with 256-bit encryption, which is very difficult to crack with so many supercomputers.

There are two types of key encryption.

                                                             1.  Symmetric

                                                             2.  Asymmetric

When the sender and the receiver share the same key to encrypt and decrypt a message then it is called as symmetric encryption. It will not available except the sender and receiver. But a public key which can be exchanged with anybody called asymmetrically. So, we can say that encryption is the most secure process for transferring data. When we send a message using an encrypted messaging service like facebook, WhatsApp.That time the service wraps takes our message in code and make an encryption key regarding that message which only the reciever of the message could decrypt.

Encryption