Chapter 2 Internet Infrastructure PDF

CIT 1006: INTERNET TECHNOLOGY AND APPLICATIONS CHAPTER 2: INTERNET INFRASTRUCTURE Ms. Ashvini Govinda Pilay Jan 2025  Objectives Overview Explain how Web pages use...

CIT 1006: INTERNET TECHNOLOGY AND APPLICATIONS CHAPTER 2: INTERNET INFRASTRUCTURE Ms. Ashvini Govinda Pilay Jan 2025  Objectives Overview Explain how Web pages use Identify and briefly describe Describe the types of Web graphics, animation, audio, the steps required for Web sites video, virtual reality, and publishing plug-ins Explain how e-mail, mailing lists, instant messaging, Describe the types of e- Identify the rules of chat rooms, VoIP, commerce netiquette newsgroups and message boards, and FTP work  The Internet The Internet is a worldwide collection of networks that links millions of businesses, government agencies, educational institutions, and individuals The World Wide Web  Evolution of the Internet An IP address is a number that uniquely identifies each computer or device connected to the Internet A domain name is the text version of an IP address Top-level domain (TLD) A DNS server translates the domain name into its associated IP address  How Domain Name System(DNS) works In a network, computer are being identified with an IP address. However, human are being identified as Names In order to have smooth communication between computer and humans, Domain Name Server was established. The purpose of domain name system is to resolve domain name to IP address.  How Domain Name System (DNS) works For example, if you would like to browse Google website, you can type in the IP address of it. But of course, with million of websites around, it’s hard to memorize IP address of each website. This is where domain server comes in and convert the domain names to IP addresses. Domain name server will search through its database and find the matching IP addresses for that domain name. Once it finds it, it resolve that domain name to the Yahoo website. Your computer able to communicate with the yahoo web server and retrieves the web pages.  How Domain Name System(DNS) works Domain Name server works like a phonebook. The searching will goes by name and not the numbers first. DNS is a protocol within the set of standards for how computers exchange data on the internet. Steps how domain name system returns the result Step 1: Type in the google.com at the browser URL. Step 2: If the web browser or the operating system, can’t find the IP address on its cache memory, it will send the query to resolver server which is basically the ISP(Internet Service Provider). Step 3:So the resolver server receives the query, it will allocate through the own cache memory to find the IP address of the google.com google.com www.google.com Steps how domain name system returns the result Step 4: If it unable to find the associated IP address, it will send the query to the root server. The root server are the top or the root of DNS server. Basically, there are 13 sets of these root servers strategically placed around the world and operated by 12 different organizations. Each set has their own unique IP address. Steps how domain name system returns the result Step 5: Once the root server receives the query, it is not going to know the IP addresses but it does know where to send the query of the resolver to find the IP address. So the root server will direct the resolver to the top level domain server for the.com domain Step 6: The resolver will ask the top level domain server for the IP address of google.com Top level domain stores the address information for top level domains such as.com,.net,.org Step 7: Once the TLD server receives the query of the google.com, it still doesn’t know the IP address, it will then direct to the authoritative name server.  Steps how domain name system returns the result Step 8: The resolve will then ask the authoritative name server for the IP address of the google.com. The authoritative is responsible for knowing everything about the domain which includes the IP address. Step 9: The authoritative name server will respond to the ISP on the IP address of google.com. Then, the google home page will be displayed at the browser. Step 10: The resolver will store the IP address on the cache memory to avoid going through all the process again Illustration between root server, top level domain and authoritative server www.google.com Evolution of the Internet The World Wide Web The World Wide Web, or Web, consists of a worldwide collection of electronic documents (Web pages) A Web site is a collection of related Web pages and associated items A Web server is a computer that delivers requested Web pages to your computer Web 2.0 refers to Web sites that provide a means for users to interact Uniform Resource Locator (URL) URL is an acronym for Uniform Resource Locator, and it is one of the core concepts of modern computing. By definition, a URL is a formatted text string referring to the location of a resource on a computer network (most commonly the web). T Typically, these resources are web pages, but they can also be text documents, graphics, programs, or pretty much anything that can be stored digitally. In addition to the "address" of the resource, a full URL will also imply the method (or protocol) by which the resource will be retrieved.  Uniform Resource Locator (URL) A basic URL will consist of three parts, or substrings, separated by defining characters: These include the protocol the host name or address resource location A simple example of a URL string would take the following form: http://www.example.com/index.html.  Anatomy of URL Given the below URL: http://www.whatever.com:80/whatever/whatever.html?this=that&that=this#fn 2 It can be break into few parts:  HTTP http:// — this is the scheme, or protocol substring, and it indicates which protocol must be used to fetch the desired file or document. While HTTP is the most common, it is by no means the only option. Other protocols include HTTPS (the secured version of HTTP), mailto: (to open a mail client), ftp: (to handle a basic file transfer), and others. The colon (:) is the URI scheme separator, and the paired forward slashes (//) define the start of the local host name.  WWW www. — this part of the URL defines the content, in this case the world wide web. This portion of a URL can also be used to indicate a subdomain. For instance, we might alter our example to include http://support.whatever.com to access an internal support page from the target website.  whatever.com whatever.com — this is the domain name, and is used to indicate the targeted host or web server. The last part of our domain name, the.com, is the domain suffix and is used to identify the type or location of the website. Other domain suffixes include.org,.net, and region specific suffixes such as.co.uk. There are over 500 domain suffixes (or gTLDs) in existence.  80 80 — this is the port, and it indicates the "gate" used to access resources on the intended web server. This part of a URL is often omitted when the web server is using standard ports for the HTTP or HTTPS protocols.  whatever/whatever.html Given the below URL: http://www.whatever.com:80/whatever/whate ver.html?this=that&that=this#fn2 whatever/whatever.html — this indicates the path to the resource on the server. Originally this section pointed to a physical location on a specific server, though now it more typically indicates an abstract location of the data being fetched. The forward slash again acts as a separator to maintain the integrity of the URL hierarchical syntac  this=that&that=this this=that&that=this — this is the query string. It consists of a question mark followed by one or more parameters which a web server can use to return specific content, or a specific version of the requested content. URLs with query strings are commonly referred to as "dynamic URLs." The parameters used in dynamic URLs are not necessarily universal, and every web server has its own rules regarding their use.  #fn2 #fn2 — the last part of URL is the optional fragment or "anchor." It is indicated by a hash (#) and is followed by some text. This is used by the browser to position that webpage at a particular location.  The World Wide Web A Web browser, or browser, allows users to access Web pages and Web 2.0 programs Internet Firefox Opera Explorer Google Safari Chrome  The World Wide Web A home page is the first Some Web pages are page that a Web site designed specifically for displays microbrowsers Web pages provide links to other related Web pages Surfing the Web Downloading is the process of receiving information  The World Wide Web A Web page has a unique address called a URL or Web address  The World Wide Web Tabbed browsing allows you to open and view multiple Web pages in a single Web browser window  The World Wide Web Two types of search tools are search engines and subject directories Search Subject engine directory Classifies Web Finds information pages in an related to a organized set of specific topic categories The World Wide Web  The World Wide Web A search engine is helpful in locating items such as: Images Videos Audio Publications People or Maps Blogs Businesses  The World Wide Web Some Web browsers contain an Instant Search box to eliminate the steps of displaying the search engine’s Web page prior to entering the search text  The World Wide Web Search operators can help to refine your search  The World Wide Web There are thirteen types of Web sites  The World Wide Web Information presented on the Web must be evaluated for accuracy No one oversees the content of Web pages  The World Wide Web Multimedia refers to any application that combines text with:  The World Wide Web A graphic is a digital representation of nontext information Graphic formats include BMP, GIF, JPEG, PNG, and TIFF  The World Wide Web A thumbnail is a small version of a larger graphic  The World Wide Web Animation is the appearance of motion created by displaying a series of still images in sequence  The World Wide Web Audio includes music, speech, or any other sound Compressed to reduce file size You listen to audio on your computer using a player Streaming is the process of transferring data in a continuous and even flow The World Wide Web  The World Wide Web Video consists of images displayed in motion  The World Wide Web Virtual reality (VR) is the use of computers to simulate a real or imagined environment that appears as a three-dimensional space  The World Wide Web A plug-in is a program that extends the capability of a Web browser Activity – Pair Work Find a website and analyze the following criteria: URL and its parts Domain name Screenshot of the homepage Identify the type of website The services provided Screenshot and give examples of the multimedia components: Graphics Animation Audio Video Virtual reality What can be searched from the search bar? List of plug-in List of functions for the website Any special features or interesting features.  The World Wide Web Web publishing is the development and maintenance of Web pages Analyze Maintain Plan a and Create a Deploy a a Web Web site design a Web site Web site site Web site  E-Commerce E-commerce is a business transaction that occurs over an electronic network M-commerce identifies e-commerce that takes place using mobile devices E-Commerce E-Commerce Business- to- consumer (B2C) E-commerce Business- Consumer- to- to- business consumer (B2B) (C2C) E-Commerce  Other Internet Services E-mail is the transmission of messages and files via a computer network An e-mail program allows you to create, send, receive, forward, store, print, and delete e- mail messages Other Internet Services  Other Internet Services A mailing list is a group of e-mail names and addresses given a single name Subscribing adds your e-mail name and address Unsubscribing removes your name  Other Internet Services Instant messaging (IM) is a real-time Internet communications service  Other Internet Services A chat is a real-time typed conversation that takes place on a computer A chat room is a location on an Internet server that permits users to chat with each other  Other Internet Services VoIP (Voice over IP) enables users to speak to other users over the Internet Also called Internet telephony  Other Internet Services A newsgroup is an online area in which users have written discussions about a particular subject Typically requires a newsreader A message board is a Web-based type of discussion group Other Internet Services FTP (File Transfer Protocol) is an Internet standard that permits file uploading and downloading with other computers on the Internet Many operating systems include FTP capabilities An FTP server is a computer that allows users to upload and/or download files using FTP Netiquette Netiquette is the code of acceptable Internet behavior Netiquette  Summary Browsing, navigating, History and structure of searching, Web World Wide Web the Internet publishing, and e-commerce Other Internet services: e-mail, instant messaging, chat rooms, Rules of netiquette VoIP, newsgroups and message boards, and FTP END