Internet and Web Technology

The Internet is the global network of computing devices including desktops, laptops, servers, tablets, mobile phones, other handheld devices, printers, scanners, routers, switches, gateways, etc. Moreover, smart electronic appliances like V, AC, refrigerator, fan, light, etc. can also communicate through a network. The list of such smart devices is always increasing e.g., drones, vehicles, door locks, security cameras.

The Internet is evolving every day and it is difficult to visualize or describe each and every aspect of its architecture of the Internet. Computers are either connected to a modem through a cable or wirelessly (WiFi). That modem, be it wired or wireless, is connected to a local Internet Service Provider (ISP) who then connects to a national network. Many such ISPs connect together to form a regional network and regional networks connect together to form a national network, and such country-wise networks form the Internet backbone.

1. The Internet: 

In simplest terms, the Internet is a global network comprised of smaller networks that are interconnected using standardized communication protocols. The Internet standards describe a framework known as the Internet protocol suite. This model divides methods into a layered system of protocols. 

These layers are as follows: 

1. Application layer (highest) – concerned with the data(URL, type, etc.). This is where HTTP, HTTPS, etc., comes in.
2. Transport layer – responsible for end-to-end communication over a network.
3. Network layer – provides data route. 

The Internet provides a variety of information and communication facilities; contains forums, databases, email, hypertext, etc. It consists of private, public, academic, business, and government networks of local to global scope, linked by a broad array of electronic, wireless, and optical networking technologies. 

2. The World Wide Web: 

The Web is the only way to access information through the Internet. It’s a system of Internet servers that support specially formatted documents. The documents are formatted in a markup language called HTML, or “HyperText Markup Language”, which supports a number of features including links and multimedia. 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. 

Difference between Web and Internet: 

URI: 

URI stands for ‘Uniform Resource Identifier’. A URI can be a name, locator, or both for an online resource whereas a URL is just the locator. URLs are a subset of URIs.  A URL is a human-readable text that was designed to replace the numbers (IP addresses) that computers use to communicate with servers.

A URL consists of a protocol, domain name, and path (which includes the specific subfolder structure where a page is located) like-

       protocol://WebSiteName.topLevelDomain/path

1. Protocol – HTTP or HTTPS.
2. WebSiteName – youngstercompany, google etc.
3. topLevelDomain- .com, .edu, .in etc.
4. path- specific folders and/or subfolders that are on a given website.

Who governs the Internet? 

The Internet is not governed and 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. 

Domain Name System

The Internet is a vast ocean where information is available in the form of millions of websites. Each website is stored on a server that is connected to the Internet, which means each server has an IP address. Every device connected to the Internet has an IP address. To access a website, we need to enter its IP address on our web browser. But it is very difficult to remember the IP addresses of different websites as they are in terms of numbers or strings.

However, it is easier to remember names, and therefore, each computer server hosting a website or web resource is given a name against its IP address. These names are called the Domain names or hostnames corresponding to unique IP addresses assigned to each server. For easy understanding, it can be considered as the phonebook where instead of remembering each person’s phone number, we assign names to their numbers. For example, the IP addresses and domain names of some websites are as follows:

DNS Server:

Instead of remembering IP addresses, we assign a domain name to each IP. But, to access a web resource, a browser needs to find out the IP address corresponding to the domain name entered. Conversion of the domain name of each webserver to its corresponding IP address is called domain name resolution. It is done through a server called DNS server. Thus, when we enter a URL on a web browser, the HTTP protocol approaches a computer server called DNS server to obtain the IP address corresponding to that domain name. After getting the IP address, the HTTP protocol retrieves the information and loads it in our browser. An example is shown in which the HTTP requests a DNS server for the corresponding IP address, and the server sends back an IP address.