Although the firm's employees are also able to connect to the Internet, special hardware devices separate the Intranet from the Internet. This security feature prohibits access to the Intranet by unauthorized users.
An extranet, a relatively new development, is a secure business-to-business network that operates within a portion of a firm's Intranet. It is used to deliver i-com-
merce by allowing, customers, suppliers, and other authorized users to access each other's proprietary intranets via the Internet. Extranets significantly decrease the transaction costs of conducting business electronically, compared to the costs of private VANS. For example, Ford Motor Co. has introduced an extranet to connect more than 15,000 Ford dealers located worldwide. The extranet supports sales and servicing of cars, with the aim of providing showroom to junk yard support to Ford customers. It includes promotional and financial information designed to aid Ford salespeople in closing deals. In addition, Ford's extranet automates the information exchange between Ford and its dealer service centers. For repair services, the dealer's repair shop can find a car's history and other information specific to its make and model, regardless of the customer's location.*
APPENDIXES TO CHAPTER 3
The appendixes to Chapter 3 on the accompanying CD-ROM provide additional coverage on the following topics:
• Appendix 3.1. Other Aspects of Client/Server (C/S) Computing: Middleware, Mod-
els of C/S, and Advantages/Limitations
• Appendix 3.2. Applications of Networks
• Appendix 3.3. Other Aspects of Specialized Systems/Networks
• Appendix 3.4. Commercial Online Networks
• Appendix 3.5. Changes Affecting Organizations and State-of-the-Art Information
Technologies and the AIS
SUMMARY
Accountants should grasp the essentials of information
technologies because these technologies are •signifi-
candy enhancing the performance of the AIS in the firms
that properly employ them. One important technology
considered is the wide-area network (WAN), which
can be organized as either a centralized or a distrib-
uted architecture. Centralized WANs offer concentrated
computing power, an integrated data base, possible
economies of scale, large processors, plus all the advan-
tages of centralized management and security. Distrib-
uted WANs offer responsiveness to user needs, optimal