MiddlewarePowerPoint PresentationInterfacesMiddleware TiersSlide 5Simple Example of n-TiersN-Tier architectureMiddlewareCSIS 4490 N-Tier Client/ServerDr. HogansonMiddleware•What is middleware?•A software interface glue that resides between the operating system (or network operating system) and the application in distributed client/server systems.Client ApplicationMiddle-wareNOSPhysical NW LayersServer ApplicationMiddle-wareNOSPhysical NW LayersMiddlewareCSIS 4490 N-Tier Client/ServerDr. Hoganson•Vertical Integration: –Between layers in each stack–Each layer interfaces with its neighbors–Between application and middleware is the API: Application Programming Interface•Horizontal Integration–Between equivalent layers located at client and server–Middleware achieves horizontal integration between client and server middlewareMiddlewareCSIS 4490 N-Tier Client/ServerDr. HogansonInterfaces•Middleware must be compatible with and interface with the network operating system•Middleware must be able to interface with the API•Compatibility issuesMiddlewareCSIS 4490 N-Tier Client/ServerDr. HogansonMiddleware TiersServer ApplicationMiddle-ware BNOSPhysical NW LayersServer ApplicationMiddle-ware ANOSPhysical NW LayersClient ApplicationMiddle-ware ANOSPhysical NW LayersMiddle-ware B2 Tier Middleware ArchitectureMiddlewareCSIS 4490 N-Tier Client/ServerDr. HogansonMiddleware TiersServer ApplicationMiddle-ware ANOSPhysical NW LayersClient ApplicationClient MiddlewareNOSPhysical NW Layers ApplicationMiddle-ware ANOSPhysical NW LayersMiddle-ware Bn-Tier Middleware Architecture (three tiers)Server ApplicationMiddle-ware BNOSPhysical NW LayersClientMiddle-wareMiddlewareCSIS 4490 N-Tier Client/ServerDr. HogansonSimple Example of n-TiersServer ApplicationMiddle-ware ASQLNOSPhysical NW LayersClient ApplicationClient MiddlewareBrowserNOSPhysical NW Layers ApplicationSQL serverNOSPhysical NW LayersVBn-Tier Middleware Architecture (3-Tier)Server ApplicationMiddle-ware BVBNOSPhysical NW LayersClientMiddle-wareHTMLMiddlewareCSIS 4490 N-Tier Client/ServerDr. HogansonN-Tier architecture•Simplifies client software–Development–Configuration & Maintenance – fewer products & protocols–(true cost of computing includes ALL personnel support costs)•Fewer client resources consumed (less memory and processing power)•De-couples the development of the server systems from the client interface•Facilitates platform