COSS Development Corporation

The COSS Internet system logical architecture divides the Web applications into these tiers or layers:

	User Interface (presentation) Layer - This layer handles HTTP requests and responses. It accepts user requests, calls the logic in the business layer and assembles HTML, XML, or PDF files to serve back to the Web client (browser) or application client.
	Business Logic Layer - This layer contains business logic components for the COSS Internet system and a set of common services such as authentication and system administration. In addition, this tier is responsible for interfacing with the Data Access Layer.
	Data Access Layer - This layer provides the data storage as well as the interface between the database and the business logic layer.
	Business System Integration Layer - This layer provides mechanisms for integrating with legacy business systems. The components in this layer can be XML, SNA, and MQ Series clients.
	Tools - COSS provides state-of-the-art tools that can be used in desktop and Web applications. The COSS toolset interacts across the 4-tier architecture.

Presentation Logic Layer
This layer is built using Active Server Page (ASP) and Visual Basic (VB) components. Together, they form the presentation layer for accepting requests from and responding to the users. ASP and VB components run under the Microsoft Internet Information (IIS) server. The following components make up the presentation layer.

	Authentication: The authentication component is responsible for authenticating users accessing sensitive areas of the system. The authentication component contains the user's security context information and provides that information to the application.
	Application Controller: The Application controller is responsible for managing the requests and responses to and from users. It knows and controls what application the users are interested in. It is also responsible for directing requests to various Web components and taking responses from the Web components to present results to users.
	Web Components: These are a set of VB components that perform many tasks between the presentation layer and the business logic layer.
	Active Server Pages (ASP): The COSS Internet system has a set of Active Server Pages. Active Server Pages glue static HTML, images, and scripting code that can activate other components. ASP generates dynamic HTML content for the Web applications.
	Presentation Outputs: The system can generate a set of presentations to users such as NAIC Ledgers, electronic forms, agent reports, and special reports.

Business Logic Layer
Business Logic is developed using Microsoft Visual Basic version 6.0. The following components reside in the Business Logic Layer of the COSS Internet system:

	Business components: These components provide business interface functions between the presentation layer and the business logic layer.
	Calculation engines:Calculation engines: Calculation engines are critical business components for insurance applications. COSS provides many calculation engines that can be plugged into the system. They are: UL/VUL calculation engine DI/LTC calculation engine Annuity calculation engine Whole Life calculation engine
	Data validation component: The data validation component is responsible for processing data from the presentation layer and applying business rules prior to the calculation engine.
	Database manager: This component encapsulates high-level database interfaces for the business logic components as well as provides the connection functions to the database.

Data Access Layer
There are several logical databases needed to support the COSS Enterprise System. They are:

	Agent database: This database contains agent information including agent name and password. The system will use the information in this database to grant control access to its resources.
	Client database: This database contains client information necessary for many applications.
	Product database: This database contains UL, VUL, DI, LTC, Annuity, and Whole Life product information.
	Rate table database: This database contains information supporting the calculation engine.
	Other database: Other databases can be added into this layer as COSS introduces new systems or functionality.

Business System Integration Layer
Integrating with legacy systems may require the installation of another middleware software product such as MQ Series or SNA server. SNA is IBM's legacy architecture, requiring computers to communicate to each other using the LU 6.2 protocol. MQ Series is popular messaging product, also from IBM, that has been adopted by companies to replace SNA. MQ Series operates on the TCP/IP protocol and has support for XML.

The COSS Internet system provides mechanisms for integration to other business systems quickly. In this tier, the Internet system will include three components: XML/XMLife, SNA integrator, and MQSeries integrator. The XML/XMLife component is used to import/export XML or XMLife data to and from the system. SNA and MQSeries components act as a client to the SNA or MQSeries servers. Together, these components help the COSS Internet system integrate with other business systems quickly.