1. CIS 325: Data Communications1 CIS-325 Data Communications Dr. L. G. Williams, Instructor

2. CIS 325: Data Communications2 Chapter Fourteen Client-Server & Intranet Applications

3. CIS 325: Data Communications3 Client-Server Basics n Clients are usually single-user PCs or workstations, with GUIs n Servers enable many clients to share access to the same data n Network provides communication services between clients and server (“many to one”)

4. CIS 325: Data Communications4 Client-Server Characteristics n Strong emphasis on bringing user-friendly, familiar apps and interface to the user n Applications are distributed, but data is centralized n Encourages the use of open and modular systems n Networking is fundamental to the process (“the network is the computer”)

5. CIS 325: Data Communications5 Advantages of Client-Server Computing n Distributed systems means redundancy and robustness n Distributed processing provides power without monopolization of resources n Modularity allows choices in hardware and software n Upgrading and growth are relatively easy

6. CIS 325: Data Communications6 Disadvantages of Client- Server Computing n Maintenance problems are more difficult with different vendors and interconnected systems n Difficult to find support tools for applications developed in-house n Requires different skills sets from software developers (Windows, Mac, RDBMS rather than COBOL, C)

7. CIS 325: Data Communications7 Client-Server Architecture n Protocols at the communication and application layers must be compatible n Hardware, operating systems, and software presentation layers can operate independently of each other –Note: In this context, presentation has to do with the application’s presentation of information to the user, not the presentation layer of the OSI model, which is concerned with formatting data

8. CIS 325: Data Communications8 Classes of Client-Server Applications n Host-based processing –traditional mainframe/central host environment; workstation role is limited to emulation n Server-based processing –Client primarily provides interface n Client-based processing –All application processing on client n Cooperative processing –Processing distributed optimally

9. CIS 325: Data Communications9 Intranets n Implementation of Internet technologies within an organization n Primarily focused on web development, with database integration n Growing at a tremendous rate

10. CIS 325: Data Communications10 Intranet Advantages n Easy and fast development of new services n Not locked into specific vendor products n Improved ability to communicate outside organization n Familiar, inexpensive interface n IDC has found that Intranets can result in ROI of as much as 1000% IDC has found that Intranets can result in ROI of as much as 1000%

11. CIS 325: Data Communications11 Typical Intranet Applications n Access to corporate databases n Organization and presentation of documentation n Communication –Intranet group mail products, eg Notes & First Class –Usenet news, implemented with local groups –Threaded bbs-style implementations

12. CIS 325: Data Communications12 Client-Server Problems n Long development cycle n Difficult to partition apps. n Difficult to distribute upgrades n Servers don’t scale up n PCs must continue to grow