Advantage of learning Computer network

It is the interconnection of multiple devices, generally termed as Hosts connected using multiple paths for the purpose of sending/receiving data or media.There are also multiple devices or mediums which help in the communication between two different devices which are known as Network devices. Ex: Router, Switch, Hub, Bridge.

OSI:

OSI stands for Open Systems Interconnection. It is a reference model that specifies standards for communications protocols and each layer's functionalities.

Protocol:
The protocol is the set of rules or algorithms which define the way how two entities can communicate across the network and there exists different protocol defined at each layer of the OSI model. Few of such protocols are TCP, IP, UDP, ARP, DHCP, FTP and so on.

UNIQUE IDENTIFIERS OF NETWORK
Host name:
Each device in the network is associated with a unique device name known as Hostname.
Type “hostname” in the command prompt and press ‘Enter’, this displays the hostname of your machine.

IP Address (Internet Protocol Address):
Also, know as the Logical Address, is the network address of the system across the network.
To identify each device in the world-wide-web, Internet Assigned Numbers Authority (IANA) assigns IPV4 (Version 4) address as a unique identifier for each device on the Internet.
The length of the IP address is 32-bits. (Hence we have 232 IP addresses available.)
Type “ipconfig” in the command prompt and press ‘Enter’, this gives us the IP address of the device.

MAC Address (Media Access Control address):
Also known as physical address, is the unique identifier of each host and is associated with the NIC (Network Interface Card).
MAC address is assigned to the NIC at the time of manufacturing.
Length of the MAC address is : 12-digit/ 6 bytes/ 48 bits
Type “ipconfig/all” in the command prompt and press ‘Enter’, this gives us the MAC address.

Port:
Port can be referred to as a logical channel through which data can be sent/received to an application. Any host may have multiple applications running, and each of these applications is identified using the port number on which they are running.

Socket:
The unique combination of IP address and Port number together are termed as Socket.

The World Wide Web:
The web is a subset of the internet. It’s a system of Internet servers that support specially formatted documents. The documents are formatted in a markup language called HTML(that supports links, multimedia, etc). These documents are interlinked using hypertext links and are accessible via the Internet.

To link hypertext to the Internet, we need:

1. The markup language, i.e., HTML.
2. The transfer protocol, e.g., HTTP.
3. Uniform Resource Locator (URL), the address of the resource.

We access the web using web browsers.

Who governs the Internet?

The Internet is not governed, it has no single authority figure. The ultimate authority for where the Internet is going rests with the Internet Society, or ISOC.
ISOC is a voluntary membership organization whose purpose is to promote global information exchange through Internet technology.

• ISOC appoints the IAB- Internet Architecture Board. They meet regularly to review standards and allocate resources, like addresses.
• IETF- Internet Engineering Task Force. Another volunteer organization that meets regularly to discuss operational and technical problems.

Some interesting facts about computer networking are:

• The Internet was invented by Tim Berners-Lee in 1989.
• The Internet is controlled by 75 million servers.
• The backbone of the internet is made by 550, 000 miles of underwater cable.
• About one billion computer systems are connected to the internet.
• About 3.2 billion people use the internet of which 1.7 billion internet users are Asians.
• The Internet consists of five billion computing devices such as computers, phones, modems, switches, routers, etc.
• According to Google, the Internet consists of 5 million Terabytes of data.
• If the internet goes down for a day, approximately 200 billion emails and 3 billion Google searches would have to wait.
• Approximately 204 million emails per minute are sending over the Internet. 70% of them are spam.
• 269 billion emails are sent per day.
• 30, 000 websites are hacked every day.
• 50 million horsepower is required by the internet to keep running in the current state.
• Approximately 9 million adults in Britain and 1/3rd of Italians have never used the internet while China has treatment camps for internet addicts.
• Microsoft has more servers than Google. Microsoft owns over one million servers while Google has 900, 000.
• Internet bots and malware generate 61.5% or nearly two-thirds of all website traffic.
• Approximately 1.7 trillion eurodollar worth of funds is spent online.
• Tim Berners-Lee was knighted by Queen Elizabeth.
• An email takes around 2 billion electrons to produce.
• Online dating generates approximately $1 billion dollars every year.
• Qwerty was designed to slow you down so that keys would not jam.

                                                 ~some sources have been used from the internet

             ----------------------Done By A.Santhosh Kumar----------------------