Transcript Chapter 2
Chapter 2 Technology Infrastructure: The Internet and the World Wide Web Infrastructure for Electronic Commerce What is the Internet? Internet – Intranet - Extranet Web-based Client/server Computing Getting Connected What is the Internet? Internet is a collection of computer networks All computers on the Internet must use same network & transport protocols TCP/IP Who runs the Internet No one runs the internet Volunteer organizations suggest changes or handle administration Internet Society Internet Assigned Number Authority Internet Research Task Force Network Information Centers Internet Architecture Board No single owner Backbone is maintained by a few telecommunication companies Everyone maintains their piece of the network - whether a university, business, or a single user at home When you get connected the Internet grows by one Failure of one network will not halt Internet traffic Packet-Switched Networks A local area network (LAN) is a network of computers close together. A wide area network (WAN) is a network of computers connected over a great distance. Circuit switching is used in telephone communication. The Internet uses packet switching • Files are broken down into small pieces (called packets) that are labeled with their origin, sequence, and destination addresses. Routing Packets ‘routers’. ‘routing algorithms’ When packets leave a network to travel on the Internet, they are translated into a standard format by the router. Routers and the telecommunication lines connecting them are referred to as ‘the Internet backbone’. Routing Packets The TCP/IP Protocol The Transmission Control Protocol (TCP) and the Internet Protocol (IP) are the two protocols that support the Internet operation. TCP controls the assembly of a message into smaller packets before it is transmitted over the Internet. The IP protocol includes rules for routing individual data packets from their source to their destination. IP Address Internet addresses are based on a 32-bit number called an IP address. IP addresses appear as a series of up to four separate numbers delineated by a period. An address such as 126.204.89.56 uniquely identifies a computer connected to the Internet. Domain Names To make the numbering system easier to use, an alternative addressing method that uses words was created. An address, such as www.course.com, is called a domain name. The last part of a domain name (i.e., ‘.com’) is the most general identifier in the name and is called a ‘top-level domain’ (TLD). Top-level Domain Names Internet Services Protocols The Internet provides a variety of services to users known as ‘application services’. Application services include Web page delivery, network management tools, remote login, file transmission, electronic mail, and directory services. Internet Applications Electronic Mail Telnet FTP SMTP, POP, and IMAP E-mail is sent across the Internet is managed and stored by mail servers. Simple Mail Transfer Protocol (SMTP) is the standard for e-mail client program. Post Office Protocol (POP) is the standard for e-mail server program. The Interactive Mail Access Protocol (IMAP) is a newer e-mail protocol. How Does The Internet Work? Server (business) Client (customer) Website Server Hardware Routers Backbone Routers Link (ISP, LAN) Connections (Modem, ISDN, etc.) TCP/IP Client Hardware Browser Internet Infrastructure Web-based Client/server Computing The client is the Web browser, or Web browser and computer, that requests Web pages and services from a server. The server is the Web server software, or Web server and software and computer, that fills client requests for Web pages and services. Server Client/Server Architecture URL Database Query Client Server Requests & Parameters TCP/IP HTTP Response & Results Disks for Storage Web Clients and Web Servers Two-Tier Client-Server Architecture Three-Tier and N-Tier ClientServer Architectures Internet – Intranet - Extranet The Internet is a network of networks composed of An intranet is a private Internet owned by a company. An extranet is an extended intranet, providing for thousands of LANs and WANs. external access. A firewall is a device, or set of devices, designed to protect a company's intranet from the Internet. Intranets An intranet is a Web-based private network that hosts Internet applications on a LAN. Intranets are an extremely popular and low-cost way to distribute corporate information. The intranet infrastructure includes a TCP/IP network, Web authoring software, Web server hardware and software, Web clients, and a firewall server. Intranets and Extranets Connectivity Overview The most common connection options that ISPs offer to the Internet are telephone, broadband, leased-line, and wireless. Bandwidth is the amount of data that can travel through a communication line per unit of time. Bandwidth can differ for data traveling to or from the ISP. Voice-Grade Telephone Connections The most common way to connect to an ISP is through a modem connected to your local telephone service provider. POTS uses existing telephone lines and an analog modem to provide a bandwidth of 28-56 Kbps. ISDN uses the DSL protocol suite to offer bandwidths between 128-256 Kbps. Broadband Connections Connections that operate at speeds of greater than 200 Kbps are called broadband services. ADSL uses the DSL protocol to provide bandwidths between 100-640 Kbps upstream and 1.5-9 Mbps downstream. Cable modems provide transmission speeds between 300 Kbps-1 Mbps from the client to the server and a downstream rate as high as 10 Mbps. Satellite microwave transmissions handle internet downloads at speeds around 500 Kbps. Leased-Line Connections Large firms can connect to an ISP using higherbandwidth connections that they can lease from telecommunications carriers. A ‘T1’ line operates at 1.544 Mbps and a ‘T3’ line operates at 44.736 Mbps. Wireless Connections Many researchers and business managers see great potential for wireless networks and the devices connected to them. The term m-commerce (mobile commerce) is used to describe the kinds of resources people might want to access using devices that have wireless connections. Getting Connected 1. 2. 3. 4. 5. 6. 7. Decide Business Objective (class #4) Research Connection Options Find an Internet Service Provider (ISP) Contract for Internet Connection Buy Hardware & Software Obtain Domain Name Turn on the Switch Research Connection Options Dialup options Modem ISDN Dedicated Connection Options Frame Relay T1 T3 Find an Internet Service Provider (ISP) ISP – is the company that you will contract with for Internet connectivity Basically two types Commercial online services ie AOL, MSN Everyone else Case study 6-2 the list List of ISPs: thelist.internet.com Buy Hardware & Software Hardware Depending on level of internet use Modem, computer, server for each service, router, gateway,CSU/DSU box Software Client software for each internet tool Server software for each internet tool Security, transaction software Obtain Domain Name Domain Name – your identity on the internet-- for the internet it is how the info gets routed. ( easier than IP #) Domain Type .ca Canada .com Commercial users .net Network providers .edu education .org organization .gov U.S. gov. .mil U.S. military .jp Japan How to get a Domain Name Case study 6-3 http://www.networksolutions.com Internet Address: Domain Name System - WWW http://www.amazon.com/buy/order.htm WWW Language (protocol) Name of Computer Server Folder or Directory File or Document What Classification? com - commercial edu - educational gov - gevernment Registered Domain Name (Name of Organization) Internet Address Internet service providers or a hosting service may obtain the domain for you for a fee, but… if their name is listed as administrative contact with InterNIC, you may have trouble switching your domain name to a new service Make sure your name is listed as the administrative contact with InterNIC Determine who “owns” yours: rs.internic.net/cgi-bin/whois Turn on the Switch