Week6 Lecture1 Publishing and Browsing the Web Publishing

Week-6 (Lecture-1) Publishing and Browsing the Web: Publishing: 1. upload the following items on the web • Google documents • Spreadsheets • Presentations • drawings 2. after publishing we get a URL (universal resource locator) of a unique page.

Week-6 (Lecture-1) What is required to publish? There are two ways to publish • A unique domain name: Each domain name is registered with a DNS (Domain Name Server), which identifies a domain name with a unique Internet Protocol (IP) address. • Web Space: Each website must have a web space allocated to it. This is provided by a web server, many of which are maintained by private companies.

Week-6 (Lecture-1) Domain names: • Used to identify one or more IP addresses • Ex. domain name microsoft. com represents about a dozen IP addresses. • Domain names are used in URLs to identify particular Web pages • Ex. in the URL http: //www. pcwebopedia. com/index. html, the domain name is pcwebopedia. com. Domain name suffix: 1. . gov - Government agencies 2. . edu - Educational institutions 3. . org - Organizations (nonprofit) 4. . mil - Military 5. . com - commercial business 6. . net - Network organizations 7. . sa – Saudi Arabia 8. th - Thailand

Week-6 (Lecture-1) Aspects of Domain names: • Internet is based on IP addresses, not domain names • Every Web server requires a Domain Name System (DNS) server • DNS translate domain names into IP addresses. Internet Address: • uniquely identifies a node on the Internet. • name or IP of a Web site • It can be URL (Universal resource Locator)

Week-6 (Lecture-1) IP address: • 32 bit number assign to n/w device. • It uses TCP/IP protocols. • Sender knows the IP address before sending any packet. • Its of two types IPv 4 (home Use) and IPv 6 (Big Organizations). • 32 - bit address use for represent 8 bit decimal no. separated by zero (0). I. e. 168. 212. 226. 204 represent 10101000. 11010100. 11100010. 1100 • Range from 0. 0 to 255 • 00000000. 0000 to 11111111. 1111

Week-6 (Lecture-1) DNS: • translates Internet domain and host names to IP addresses. • automatically converts the names we type in our Web browser address bar to the IP addresses of Web servers hosting those sites. • DNS implements a distributed database to store this name and address • DNS assumes IP addresses do not change (are statically assigned rather than dynamically assigned). Subnet mask: • Another 32 bit no. • Acts like a filter when applied on 32 -bit IP address. • By use of subnet mask system can determine which portion of IP address.

Week-6 (Lecture-2) What is World Wide Web (WWW)? • Global interactive, dynamic, cross platform • Graphical hypertext information system that runs on the Internet. Web Browser: • Special software to show web page • Ex. Internet Explorer, Mozilla Firefox • Web pages available on the web server and show on client.

Week-6 (Lecture-2) URL: • address of a specific Web site or file on the Internet • uses forward slashes ( / ) to denote different directories • Ex. http: //www. cnet. com/ http: //web. mit. edu/ ftp: //info. apple. co/ Web Page: • Single document written in HTML ( Hypertext Markup Language ) • Includes the text of the document, its structure, any links • Ex. documents and graphic images and other media.

Week-6 (Lecture-2) Home page: • The first page of a website • Automatically listed on the server • It has all the main features and important Hyperlinks of that website. Search Engine: • A software system • Designed to search for information • Search information may be the Web pages, images etc. • It works on an algorithm or web crawler • Ex. Archie, Gopher

Week-6 (Lecture-2) How search Engine Works? Ans. A search engine main 3 processes 1. Web crawling Search by Web crawling from site to site by spider in systematic way. 2. Indexing • Collect, parses and store data for fast information retrieval • Ex. Meta search engines

Week-6 (Lecture-2) 3. Searching: • Use a search query to search. • Three types of web query 1. Informational queries 2. navigational queries 3. Transactional queries Most popular search engines: • Google search • Bing • Yahoo Search • Ask • Ao. I Search