Oct 2000C.Watters1 Internet for E-Commerce Internet, Intranet, Extranet Basics

Oct 2000C.Watters2 Objectives I.Difference between internet/intranet/extranet II.Understand the Internet  How big is it anyway?  How is it constructed  Last mile?  What are the protocols III.What is the World Wide Web (WWW)

Oct 2000C.Watters3 I. Internet/Intranet/Extranet Internet: public communication network –No single owner –No single authority Intranet: uses Internet network (usually) –Restricted access –Corporate or government Extranet: uses Internet network (usually) –Restricted access –Business partners Is this like EDI? How can that work?? Are we talking firewalls?

Oct 2000C.Watters4 The Internet: Public Global Network

Oct 2000C.Watters5

Oct 2000C.Watters6 Digital Divide

Oct 2000C.Watters7 Size of the Internet

Oct 2000C.Watters8 I. The Internet No quality control No central control No guarantees of delivery No guarantees of security No guarantees of privacy No place where the “buck stops”

Oct 2000C.Watters9 What is an internet anyway? 2 or more networks that can communicate

Oct 2000C.Watters10 Big Picture Backbone: long distance high bandwidth networks –Mostly fibre optic –Satellite –Radio –microwave

Oct 2000C.Watters11 CA*net3 Physical Links

Oct 2000C.Watters12 The Last Mile (your home or office) ConnectionTransfer Time (10Mbyte file) 14.4 kbps1.5 hours 28.8 kbps46 minutes 128 kbps ISDN10 min 1.5 Mbps T-152 secs 4 Mbps cable20 secs 8 Mbps ADSL10 secs 10 Mbps cable8 secs

Oct 2000C.Watters13 Last Mile Technologies ADSL (Asymmetric Digital Subscriber Line) –Uses existing phone line Wireless – using radio frequencies –Currently about 11 kbps thruput –G3 should be 2Mbps Cable –Share bandwidth with all users

Oct 2000C.Watters14 Internet Protocols (some)  Protocol stacks for standardization  TCP/IP Protocols for moving data across the Internet

Oct 2000C.Watters15 ISO OSI model

Oct 2000C.Watters16 INTERNET MODEL LAYERS  Application layer  communication services (ftp, telnet, )  transport layer  transmission of messages end-to-end  network layer  transmission of messages sequence of links  link layer  transmission of packet across one link

Oct 2000C.Watters17 Internet network layers

Oct 2000C.Watters18 TCP/IP applications TCP/IP software usually supports: –remote terminal client using TELNET protocol for remote login –electronic mail client using SMTP protocol to transfer to remote system –file transfer client using FTP protocol to transfer files between 2 machines

Oct 2000C.Watters19 Transport layer: TCP and UDP TCP –transmission control protocol –full duplex byte stream –virtual path (connected) –error free –uses acknowledgements –16 bit address of ports UDP –user datagram protocol –connectionless –no acknowledgements –no flow control –no resending of erroneous packets –some error detection –16 bit port addresses

Oct 2000C.Watters20 Network Layer: IP Delivers packets up to 64kbytes, 1 at a time Each packet has a header –sending host and intended host network addresses –32 bit addresses IP layer (like UDP) – unreliable –connectionless

Oct 2000C.Watters21 TCP and IP

Oct 2000C.Watters22 TCP/IP Suite of protocols made the standard for the Internet facilitates communication between heterogeneous and similar networks that are connected together

Oct 2000C.Watters23 Physical Layer

Oct 2000C.Watters24 Data encapsulation using TCP on Ethernet

Oct 2000C.Watters25 What do we do with the Internet? Distribute applications Share document access (WWW) Share Data access (80% of web accesses)

Oct 2000C.Watters26 Client-Server Model

Oct 2000C.Watters27 Software parts Client: makes requests, eg. Browser Server: fills requests, eg. Apache Proxy server: between Client and Server to filter requests and/or responses Firewall: between client intranet and Internet

Oct 2000C.Watters28 Client-Server Model with Proxy proxy

Oct 2000C.Watters29 Client-Server Model & Firewall

Oct 2000C.Watters30 II. Intranet Corporate network using Internet technology but secured behind a firewall Uses TCP/IP like the Internet Operate as a private network Connected to the Internet thru firewall

Oct 2000C.Watters31 Public/External Internet Users Intranet Clients Servers ERP Legacy systems servers Web servers Databases Firewalls 31 An Intranet © Prentice Hall, 2000

Oct 2000C.Watters32 Federal Express – Package Intranet Intranet Case Study –60 internal web sites allow communication worldwide between divisions and corporate headquarters on all issues of importance to the employees and customers –The package tracking customers restricted access to the intranet to find the status of a package that they have shipped or one that they are expecting –The intranet includes retailers that ship products directly to customers. FedEx does the shipping.

Oct 2000C.Watters33 III. Extranet An extended intranet that connects remote intranets Uses TCP/IP Internet protocols Employs secure channels between the intranets VPN is technology that provides this virtual private network on the Internet

Oct 2000C.Watters34 Tunneling Internet Extranet Intranet Firewall Intranet Firewall 34 An Extranet Suppliers VPN Distributors VPN Customers VPN © Prentice Hall, 2000

Oct 2000C.Watters35 Virtual Private Network (VPN) VPN is a secure network on the Internet using tunneling schemes The major objective of a VPN is to use the Internet rather than a private line ($$) When two sites are connected across a VPN, each must have a VPN-capable router, firewall, or VPN access device installed When VPN is used to link mobile clients with Internet dial-up connections, the laptops must be equipped with VPN client software equipped with the addresses and associated encryption keys for corporate host sites Virtual Private Network (VPN)

Oct 2000C.Watters36 Enterprise Consumers Suppliers Clients Business Partners Distributors VPN Internet Intranet Extranet Intranet VPN Remote Employees Basic Concept of Extranets Revisited © Prentice Hall, 2000

Oct 2000C.Watters37 Industry Specific Extranet Solutions Customer Real Estate Industry/manufacturing Travel Financial services Computers Information services % of respondent Business & professional Percentage of Extranet Application Industries

Oct 2000C.Watters38 Reduced Product Development Cycle Time: Caterpillar, Inc. –Customers can use the extranet to retrieve and modify detailed order information while the vehicle remains on the assembly line Extranet Cases Toshiba –Dealers can place orders and check accounts Sears –Suppliers for just-in-time production

Oct 2000C.Watters39 III. So, what is the web? The Web (aka World Wide Web) is a protocol that uses the Internet as the communication structure links documents stored in computers that are exchanged using the Internet Based on HTTP protocol

Oct 2000C.Watters40 Recap Intranets and Extranets use the Internet The Internet is huge and uncontrolled The Last Mile remains a problem The Internet works because of shared protocols TCP/IP is the workhorse protocol