Title:Basic lesson before starting internet By: Amritpal singh sandhu Roll no: 115355 1
Main Points:ModemTypes of NetworksTypes of Transmission MediaThe InternetThe Global Internet
Modem Functions of the ModemThe digital signals can be sent to other computers overanalog cables such as telephone lines. Note that digitalsignals are representations of the two binary digits, 0 and1, and are represented as on and off electrical pulses. Figure 7-5
Modem• Signals: digital vs. analog • A modem is a device that translates digital signals from a computer into analog form so that they can be transmitted over analog telephone lines. • The modem also translates analog signals back into digital form for the receiving computer.
Types of Networks• Types of networks 1. Local-area networks (LANs) • Client/server or peer-to-peer • Ethernet – • dominant LAN standard at the physical network level • Specifying the physical medium to carry signals between computers • Data transfer rate: 10 Mbps • New version: Fast Ethernet and Gigabit Ethernet • Topologies: star, bus, ring
Management Information Systems Chapter 7 Telecommunications, the Internet, and Wireless Technology Communications Networks Network TopologiesFigure 7-6The three basic networktopologies are the bus,star, and ring.
Types of Networks• In a star topology all devices on the network connect to a single hub and all network traffic flows through the hub• In a bus topology one station transmits signals, which travel in both directions along a single transmission segment. All of the signals are broadcast in both directions to the entire network. All machines on the network receive the same signals, and software installed on the client’s enables each client to listen for messages addressed specifically to it
Types of Networks• A ring topology connects network components in a closed loop. Messages pass from computer to computer in only one direction around the loop, and only one station at a time may transmit. The ring topology is primarily found in older LANs using Token Ring networking software
Types of Transmission Media• Physical transmission media • Twisted wire (modems) • Coaxial cable • Fiber optics and optical networksMany of the telephone systems in buildings had twisted wires installed for analog communication, but they can be used for digital communication as well. Also, today, telecommunications companies are starting to bring fiber optic cable into the home for high-speed Internet access.
Types of Transmission Media• Wireless transmission media and devices • Microwave • Satellites • Cellular telephones• Transmission speed • Hertz • Bandwidth
Management Information Systems Chapter 7 Telecommunications, the Internet, and Wireless Technology Communications Networks BP Amoco’s Satellite Transmission SystemFigure 7-7Communication satellites help BP Amoco transfer seismic data betweenoil exploration ships and research centers in the United States.
The Internet• What is the Internet?• Connecting to the Internet • Internet service providers (ISPs) • Services • DSL, cable, satellite, T lines (T1, T3) • T lines are leased, dedicated lines suitable for businesses or government agencies requiring high-speed guaranteed service levels.
The Internet• Internet addressing and architecture • IP addresses (Define?) • The domain name system • Hierarchical structure • Top-level domains
The Internet The Domain Name SystemFigure 7-8The Domain Name System is ahierarchical system with a rootdomain, top-level domains,second-level domains, and hostcomputers at the third level.
The Internet• The Future Internet • The IP addresses currently in use, such as 126.96.36.199 are part of a specification called IP v 5. However, given the growth rate of the Internet, there aren’t enough IP addresses in this scheme to last beyond 2013. IP v 6 is a revised addressing convention that will provide over a quadrillion addresses • IPv6 • Internet2, NGI
The Internet• Internet services • E-mail • Chatting and instant messaging • Newsgroups • File Transfer Protocol (FTP) • World Wide Web• Voice over IP (VoIP)• Unified communications: When firms are able to merge disparate communications modes into a single universally accessible service• Virtual private networks (VPNs): is a secure, encrypted, private network that has been configured within a public network to take advantage of the economies of scale and management facilities of large
The Internet Client/Server Computing on the InternetFigure 7-10Client computers running Webbrowser and other software canaccess an array of services on serversover the Internet. These services mayall run on a single server or onmultiple specialized servers.
The Internet How Voice over IP WorksAn VoIP phone call digitizes and breaks up a voice message into data packets that may travel along different routes beforebeing reassembled at the final destination. A processor nearest the call’s destination, called a gateway, arranges the packetsin the proper order and directs them to the telephone number of the receiver or the IP address of the receiving computer. Figure 7-11
The Internet• An VoIP phone call digitizes and breaks up a voicemessage into data packets that may travel alongdifferent routes before being reassembled at the finaldestination.• A processor nearest the call’s destination, called agateway, arranges the packets in the proper order anddirects them to the telephone number of the receiveror the IP address of the receiving computer.•Skype, acquired by eBay, offers free VoIP worldwideusing a peer-to-peer network.
The Internet A Virtual Private Network Using the InternetThis VPN is a private network of computers linked using a secure “tunnel” connection over the Internet. It protects data transmittedover the public Internet by encoding the data and “wrapping” them within the Internet Protocol (IP). By adding a wrapper around anetwork message to hide its content, organizations can create a private connection that travels through the public Internet. Figure 7-12
The Internet• The World Wide Web • HTML (Hypertext Markup Language): • Formats documents for display on Web • Hypertext Transfer Protocol (HTTP): • Communications standard used for transferring Web pages • Uniform resource locators (URLs): • Addresses of Web pages • E.g., http://www.megacorp.com/content/features/082 602.html • Web servers • Software for locating and managing Web pages
The Global Internet• Search engines • Started in early 1990s as relatively simple software programs using keyword indexes • Google visited 50 billion web pages in 2007 • Today, major source of Internet advertising revenue via search engine marketing, using complex algorithms and page ranking techniques to locate results • Sponsored links vs. organic search results
The Global Internet• At the foundation of Google’s search engine are two concepts – page ranking and the indexing of combinations of words• How google works?• The Google search engine is continuously crawling the Web, indexing the content of each page, calculating its popularity, and storing the pages so that it can respond quickly to user requests to see a page. The entire process takes about one-half second.• Shopping bots • Use intelligent agent software for searching Internet for shopping information
The Global Internet How Google WorksFigure 7-13The Google search engine iscontinuously crawling theWeb, indexing the content ofeach page, calculating itspopularity, and storing thepages so that it can respondquickly to user requests tosee a page. The entireprocess takes about one-halfsecond.
The Global Internet Major Web Search EnginesThis graphic ranks the major search engines according to popularity, or percentage oftotal number of searches performed. Google is a clear favorite. Is this due to thesuperiority of their search engine or does it involve other factors?