IWT Internet and Web Technology Google literally processes

IWT Internet and Web Technology Google literally processes 2. 4 million searches every minute. In that same span of time, 700, 000 people login to Facebook and Amazon sells over $200, 000 of physical and digital goods. 701, 389 logins on Facebook 69, 444 hours watched on Netflix 150 million emails sent 1, 389 Uber rides 527, 760 photos shared on Snapchat 51, 000 app downloads on Apple’s App Store $203, 596 in sales on Amazon. com 120+ new Linkedin accounts 347, 222 tweets on Twitter 28, 194 new posts to Instagram 38, 052 hours of music listened to on Spotify 1. 04 million vine loops 2. 4 million search queries on Google 972, 222 Tinder swipes 2. 78 million video views on Youtube 20. 8 million messages on Whats. App That’s a lot of data every minute, and this volume of information is part of the reason that these same companies are prioritizing the ability to process and interpret big data more than ever before. IWT | GKS

IWT | GKS

Table of Content A timeline on the History of Internet 4 WWW vs Internet 5 Internet vs Intranet vs Extranet 7 How a website works 9 Domain Name Server and IP Addresses-Mapping 11 Web 2. 0 14 Hypertext Transfer Protocol 17 Tier architecture 29 Web Server 35 Web browser 40 Web sites 41 IWT | GKS | Page 3

A timeline on the History of Internet 1969 - ARPANET 1972 – E-mail 1974 – TCP/IP 1982 – The name “Internet” 1984 – DNS 1990 – WWW protocol 1991 – The first website 1993 – The first Graphical browser mosaic For More Information Visit: http: //www. computerhistory. org/internethistory/ IWT | GKS | Page 4

WWW vs Internet IWT | GKS | Page 5

WWW vs Internet contd. . No one actually owns the Internet, and no single person or organization controls the Internet in its entirety. The Internet is more of a concept than an actual tangible entity, and it relies on a physical infrastructure that connects networks to other networks. Tim Berners-Lee invented the World Wide Web in 1989. He founded and Directs the World Wide Consortium (W 3 C) the forum for technical development of the Web. https: //www. w 3. org/People/Berners-Lee/ There are many organizations, corporations, governments, schools, private citizens and service providers that all own pieces of the infrastructure, but there is no one body that owns it all. There are, however, organizations that oversee and standardize what happens on the Internet and assign IP addresses and domain names, such as the National Science Foundation, the Internet Engineering Task Force, ICANN, Inter. NIC and the Internet Architecture Board. For details refer: https: //www. lifewire. com/history-of-world-wide-web-816583 IWT | GKS | Page 6

Internet vs Intranet vs extranet Internet is a clustered system of interrelated computer networks that uses a standard Internet protocol (IP) or transmission control protocol (TCP) network. It is a global network of millions of private, public and organizational network. It carries a massive range of informational resources and data in form of HTTP (Hypertext Markup language) documents and applications through World Wide Web (WWW). Common functions of sharing are: email, file sharing, telephony and p 2 p networks. Intranet is a computer network system in which a specific organizational systems share information, computing services and operational systems with each other by using an Internet (IP) technology. This term basically refers to the network of a specific organization. You can also says it a private network. Authenticated users of the organization can access the database system, search engines, directory and can distribute documents and workflow. IWT | GKS | Page 7

Internet vs Intranet vs extranet. . Extranet The term Extranet is linked with Intranet. Extranet is a kind of computer network that allows the outside users to access the Intranet of organization. This network system is basically used for business to business (B 2 B) purposes. This system basically allows the outside users of an organization, like partners, suppliers, vendors and other stakeholders to remain in touch with the activities of organization. IWT | GKS | Page 8

How a website works A user enters a URL into a browser (for example, Google. com. This request is passed to a domain name server. The domain name server returns an IP address for the server that hosts the Website (for example, 68. 178. 157. 132). The browser requests the page from the Web server using the IP address specified by the domain name server. The Web server returns the page to the IP address specified by the browser requesting the page. The page may also contain links to other files on the same server, such as images, which the browser will also request. The browser collects all the information and displays to your computer in the form of Web page. IWT | GKS | Page 9

How a website works contd IWT | GKS | Page 10

Domain Name Server and IP Addresses-Mapping The Domain Name System (aka DNS) is used to resolve human-readable hostnames like www. google. com into machine-readable IP addresses like 204. 13. 248. 115. DNS also provides other information about domain names, such as mail services. What is DNS server and how does it work? Domain Name Servers (DNS) are the Internet's equivalent of a phone book. They maintain a directory of domain names and translate them to Internet Protocol (IP) addresses. This is necessary because, although domain names are easy for people to remember, computers or machines, access websites based on IP addresses. IWT | GKS | Page 11

Domain Name Server and IP Addresses-Mapping Google DNS IP Addresses Google maintains the IP addresses 8. 8 and 8. 8. 4. 4 as the primary and secondary DNS addresses for Google Public DNS. A network of DNS servers strategically located around the world support queries at these addresses. Commands: C: ipconfigall Or tracert www. google. com Important links for more information: http: //www. uxworld. com/? p=384 https: //computer. howstuffworks. com/dns. htm IWT | GKS | Page 12

Domain Name Server and IP Addresses-Mapping IWT | GKS | Page 13

Web 2. 0 IWT | GKS | Page 14

Web 2. 0 IWT | GKS | Page 15

Web 2. 0 IWT | GKS | Page 16

Hypertext Transfer Protocol The Hypertext Transfer Protocol (HTTP) is an application-level protocol for distributed, collaborative, hypermedia information systems. This is the foundation for data communication for the World Wide Web (i. e. internet) since 1990. How HTTP Works HTTP is an application layer protocol built on top of TCP that uses a client-server communication model. IWT | GKS | Page 17

Hypertext Transfer Protocol HTTP clients and servers communicate via HTTP request and response messages. The three main HTTP message types are GET, POST, and HEAD. HTTP GET messages sent to a server contain only a URL. Zero or more optional data parameters may be appended to the end of the URL. The server processes the optional data portion of the URL, if present, and returns the result (a web page or element of a web page) to the browser. HTTP POST messages place any optional data parameters in the body of the request message rather than adding them to the end of the URL. HTTP HEAD request works the same as GET requests. Instead of replying with the full contents of the URL, the server sends back only the header information (contained inside the HTML section). IWT | GKS | Page 18

Hypertext Transfer Protocol PUT - Replaces all current representations of the target resource with the uploaded content. DELETE - Removes all current representations of the target resource given by a URI. CONNECT - Establishes a tunnel to the server identified by a given URI. OPTIONS - Describes the communication options for the target resource. TRACE - Performs a message loop-back test along the path to the target resource. Refer for details: https: //www. tutorialspoint. com/http_methods. htm IWT | GKS | Page 19

Hypertext Transfer Protocol Persistent connections: ØIn HTTP/0. 9 and 1. 0, the connection is closed after a single request/response pair. ØIn HTTP/1. 1 a keep-alive-mechanism was introduced, where a connection could be reused for more than one request. ØAnother positive side effect is that in general the connection becomes faster with time due to TCP's slow-start-mechanism. IWT | GKS | Page 20

Hypertext Transfer Protocol HTTP session state : ØHTTP is a stateless protocol. ØA stateless protocol does not require the HTTP server to retain information or status about each user for the duration of multiple requests. ØHowever, some web applications implement states or server side sessions using for instance HTTP cookies or hidden variables within web forms. IWT | GKS | Page 21

Hypertext Transfer Protocol HTTP status codes : In HTTP/1. 0 and since, the first line of the HTTP response is called the status line and includes a numeric status code (such as "404") and a textual reason phrase(such as "Not Found"). HTTP status code is primarily divided into five groups for better explanation of request and responses between client and server as named: Informational 1 XX, Successful 2 XX, Redirection 3 XX, Client Error 4 XX and Server Error 5 XX. List of HTTP status codes: https: //en. wikipedia. org/wiki/List_of_HTTP_status_codes IWT | GKS | Page 22

Hypertext Transfer Protocol The browser initiates communication with an HTTP server by initiating a TCP connection to the server. Web browsing sessions use server port 80 by default although other ports such as 8080 are sometimes used instead. Once a session is established, the user triggers the sending and receiving of HTTP messages by visiting the web page. Example session Below is a sample conversation between an HTTP client and an HTTP server running on www. example. com, port 80. All the data is sent in a plain-text (ASCII) encoding, using a two-byte CR LF ('rn') line ending at the end of each line. IWT | GKS | Page 23

Hypertext Transfer Protocol Client request A client request (consisting in this case of the request line and only one header field) is followed by a blank line, so that the request ends with a double newline, each in the form of a carriage return followed by a line feed. The "Host" field distinguishes between various DNS names sharing a single IP address, allowing name-based virtual hosting. While optional in HTTP/1. 0, it is mandatory in HTTP/1. 1. IWT | GKS | Page 24

Hypertext Transfer Protocol Server response List of HTTP status codes: https: //en. wikipedia. org/wiki/List_of_HTTP_status_codes IWT | GKS | Page 25

History of HTTP Tim Berners-Lee created the initial HTTP in the early 1990 s as part of his work in defining the original World Wide Web. Three primary versions were widely deployed during the 1990 s: ØHTTP 0. 9 (for support of basic hypertext documents) - 1991 ØHTTP 1. 0 (extensions to support rich websites and scalability) - 1996 ØHTTP 1. 1 (developed to address performance limitations of HTTP 1. 0, specified in Internet RFC 2068) - 1997 The latest version, HTTP 2. 0, became an approved standard in 2015. It maintains backward compatibility with HTTP 1. 1 but offers additional performance enhancements. IWT | GKS | Page 26

HTTPS ØHTTP Secure (HTTPS) is an adaptation of the Hypertext Transfer Protocol (HTTP) for secure communication over a computer network, and is widely used on the Internet. ØIn HTTPS, the communication protocol is encrypted by Transport Layer Security (TLS), or formerly, its predecessor, Secure Sockets Layer (SSL). It adds an additional feature – encryption. The data sent to and from the server are encrypted by both the client and the server. Hence, the request as well as the data retrieved are both secured. IWT | GKS | Page 27

HTTP vs HTTPS IWT | GKS | Page 28

Two tier architecture The two-tier is based on Client Server architecture. The two-tier architecture is like client server application. The direct communication takes place between client and server. There is no intermediate between client and server. Because of tight coupling a 2 tiered application will run faster. IWT | GKS | Page 29

Two tier architecture IWT | GKS | Page 30

Three tier architecture Three-tier architecture typically comprise a presentation tier, a business or data access tier, and a data tier. Three layers in the three tier architecture as follows: IWT | GKS | Page 31

Three tier architecture IWT | GKS | Page 32

Three tier architecture IWT | GKS | Page 33

Technology in Three tier web architecture IWT | GKS | Page 34

Web Server A Web server is a program that uses HTTP (Hypertext Transfer Protocol) to serve the files that form Web pages to users, in response to their requests, which are forwarded by their computers' HTTP clients. Dedicated computers and appliances may be referred to as Web servers as well. Examples Key Points When client sends request for a web page, the web server search for the requested page if requested page is found then it will send it to client with an HTTP response. If the requested web page is not found, web server will the send an HTTP response: Error 404 Not found. If client has requested for some other resources then the web server will contact to the application server and data store to construct the HTTP response IWT | GKS | Page 35

Working of a Web Server ØWeb server respond to the client request in either of the following two ways: ØSending the file to the client associated with the requested URL. ØGenerating response by invoking a script and communicating with database IWT | GKS | Page 36

Popular Web Servers in market There are four leading web servers − Apache, IIS, lighttpd and Jagsaw. Now we will see these servers in bit more detail. Apart from these Web Servers, there are other Web Servers also available in the market but they are very expensive. Major ones are Netscape's i. Planet, Bea's Web Logic and IBM's Web. Sphere. This is the most popular web server in the world developed by the Apache Software Foundation. Apache web server is an open source software and can be installed on almost all operating systems including Linux, Unix, Windows, Free. BSD, Mac OS X and more. About 60% of the web server machines run the Apache Web Server. You can have Apache with tomcat module to have JSP and J 2 EE related support. IWT | GKS | Page 37

Popular Web Servers in market The Internet Information Server (IIS) is a high performance Web Server from Microsoft. This web server runs on Windows NT/2000 and 2003 platforms ( and may be on upcoming new Windows version also). IIS comes bundled with Windows NT/2000 and 2003; Because IIS is tightly integrated with the operating system so it is relatively easy to administer it. The lighttpd, pronounced lighty is also a free web server that is distributed with the Free. BSD operating system. This open source web server is fast, secure and consumes much less CPU power. Lighttpd can also run on Windows, Mac OS X, Linux and Solaris operating systems. This web server from Sun Microsystems is suited for medium and large websites. Though the server is free it is not open source. It however, runs on Windows, Linux and Unix platforms. The Sun Java System web server supports various languages, scripts and technologies required for Web 2. 0 such as JSP, Java Servlets, PHP, Perl, Python, Ruby on Rails, ASP and Coldfusion etc. IWT | GKS | Page 38

Popular Web Servers in market Jigsaw (W 3 C's Server) comes from the World Wide Web Consortium. It is open source and free and can run on various platforms like Linux, Unix, Windows, Mac OS X Free BSD etc. Jigsaw has been written in Java and can run CGI scripts and PHP programs. IWT | GKS | Page 39

Web Browsers are software installed on your PC. To access the Web, you need a web browser, such as Netscape Navigator, Microsoft Internet Explorer or Mozilla Firefox. While developing a site, we should try to make it compatible to as many browsers as possible. Especially sites should be compatible to major browsers like Explorer, Firefox, Chrome, Netscape, Opera, and Safari. IWT | GKS | Page 40

Web Sites Website is a location on web and is hosted on a web server. It is a set of related web pages. It is accessed using Internet address known as Uniform Resource Locator Static Websites Static websites are also known as flat or stationary websites. They are loaded on the client’s browser as exactly they are stored on the web server. Such websites contain only static information. User can only read the information but can’t do any modification or interact with the information. Static websites are created using only HTML. Static websites are only used when the information is no more required to be modified. IWT | GKS | Page 41

Web Sites contd. . Dynamic Websites Dynamic websites shows different information at different point of time. It is possible to change a portion of a web page without loading the entire web page. It has been made possible using Ajax technology. Server-side dynamic web page It is created by using server-side scripting. There are server-side scripting parameters that determine how to assemble a new web page which also include setting up of more client-side processing. Client-side dynamic web page It is processed using client side scripting such as javascript. And then passed in to Document Object Model (DOM). IWT | GKS | Page 42

Web Sites contd. . Dynamic Websites Dynamic websites shows different information at different point of time. It is possible to change a portion of a web page without loading the entire web page. It has been made possible using Ajax technology. Server-side dynamic web page It is created by using server-side scripting. There are server-side scripting parameters that determine how to assemble a new web page which also include setting up of more client-side processing. Client-side dynamic web page It is processed using client side scripting such as javascript. And then passed in to Document Object Model (DOM). IWT | GKS | Page 43

Web Sites contd. . IWT | GKS | Page 44