ocr: Twoter threetrar Eusmess Bushess Application Application Web Server Constituency Constituency Ditectory Mainframe Services Busness Database Appication services: Veb server: Constituency, Appl Server. Figure 1. One of the basic tenants of the model is a network-centric infrastructure. The model connects users, applications, services, data, and business rules in one vast patchwork of flexiblo and open networks.