Chapter 10The Internet: A Network of NetworksInternet ServicesSlide 4Counting ConnectionsInternet ProtocolsSlide 7Slide 8Internet AddressesSlide 10Slide 11Slide 12Internet Access OptionsInternet Applications: Communication and ConnectionSlide 15Slide 16Slide 17Inside the WebSlide 19Slide 20Slide 21Web AddressesSlide 23Publishing on the WebPublishing on the WebSlide 26From Hypertext to MultimediaSlide 28Beyond HTMLSlide 30Slide 31Slide 32 2002 Prentice HallChapter 10Inside the Internet and the Web 2002 Prentice Hall 2 The Internet is an interconnected network of thousands of networks linking academic, research, government, and commercial institutions.The Internet: A Network of Networks 2002 Prentice Hall 3 The Internet provides scientists, engineers, educators, students, business people, and others with a variety of services such as:Electronic mail (send/receive mail messages)Remote login (Telnet - access to other computers)Internet Services 2002 Prentice Hall 4 Internet ServicesTransferring files (FTP - accessing archives of data)Newsgroups (Usenet - on-line public discussions)World Wide Web (a collection of multimedia documents) 2002 Prentice Hall 5 Counting ConnectionsToday, the Internet connects computers to about every country in the world. However, the Internet is:growing too fast to measure its growthtoo decentralized to quantifya network with no hard boundaries 2002 Prentice Hall 6 The language at the heart of the Internet is TCP/IP… Transmission Control Protocol/Internet Protocol Allows cross-network communicationInternet Protocols 2002 Prentice Hall 7 Internet ProtocolsTCP breaks messages into packetsEach packet has all the information needed to travel from network to networkHost systems called Routers determine how to route transmissions 2002 Prentice Hall 8 Internet ProtocolsIP is the address for the packetsEach Internet host computer has a unique IP Address Each address is comprised of four sets of numbers separated by periods, such as 123.23.168.22 2002 Prentice Hall 9 Internet AddressesThe host is named using DNS (domain name system), which translates IP addresses into a string of names.“Each person on the “Internet” has a unique e-mail “address” created by having a squirrel run across a computer keyboard.”Dave Barry 2002 Prentice Hall 10 Internet AddressesTop level domains include:.edu - educational sites.com - commercial sites.gov - government sites.mil - military sites.net - network administration sites.org - nonprofit organizations 2002 Prentice Hall 11 Internet AddressesAn Internet address includes: [email protected]username is the person’s “mailbox”hostname is the name of the host computer and is followed by one or more domains separated by periods:–host.subdomain.domain–host.domain–host.subdomain.subdomain.domain 2002 Prentice Hall 12 Internet [email protected]:[email protected] President whose mail is stored on the host whitehouse in the government domainUser hazel_filbert at the server for Lane County, Oregon, k-12 school district 2002 Prentice Hall 13 Internet Access Options Internet Service Providers (ISPs)local ISPs provide connections through local telephone linesnational ISPs offer connections on a nationwide scale 2002 Prentice Hall 14 The Internet uses the client/server model for most Internet applications. In the client/server model a client program asks for information, and a server program fields the request and provides the requested information from databases and documents. Internet Applications:Communication and Connection 2002 Prentice Hall 15 An email server acts like a local post office for a particular Internet host—a business, an organization, or an ISP. File servers are common within LANs, but they’re also used to share programs, media files, and other computer data across the Internet. Internet Applications:Communication and Connection 2002 Prentice Hall 16 File transfer protocol (FTP) allows users to download files from remote servers to their computers and to upload files.File compression saves storage space on disk and saves transmission time when files are transferred through networks. Internet Applications:Communication and Connection 2002 Prentice Hall 17 An application server stores applications- PC office applications, databases, or other applications - and makes them available to client programs that request them. An application server might be housed at an application service provider (ASP) - a company that manages and delivers application services on a contract basis. A Web server stores Web pages and sends pages to client Web browsers.Internet Applications:Communication and Connection 2002 Prentice Hall 18 WWW is a distributed browsing and searching system developed at CERNSystem was designed to give Internet documents unique addressesHTML language was created for encoding and displaying documentsBrowser software was built for viewing documents from remote locationsInside the Web 2002 Prentice Hall 19 Inside the WebWeb pages are made up of text and imagesA Web site is a collection of web pagesA Home page is the main entry to a Web siteA Web browser like Netscape Communicator or Internet Explorer allows you to explore the Web by clicking linksWeb site Jargon: 2002 Prentice Hall 20 Inside the Web Hyperlinks (links) are words or pictures that act as buttons, allowing you to go to another Web pageLinks are typically underlined or displayed in a different color 2002 Prentice Hall 21 Inside the WebMore Web site JargonLinks allow you to locate information without knowing its exact location (it may move from time to time)Back and Forward buttons let you retrace your stepsBookmarks and Favorites can be set up to mark your favorite Web locations 2002 Prentice Hall 22 Web AddressesA typical URL looks like this:http://www.prenhall.com/beekman 2002 Prentice Hall 23 Web AddressesProtocol for Web pages Dissecting Web Page address:http://www.vote-smart.org/Path to the hostResource