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MSF Design. Logical Design Physical Design. Logical Design. Takes each piece of conceptual design and assigns it to a specific logical tier of presentation, business, or data level architecture.
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MSF Design • Logical Design • Physical Design
Logical Design • Takes each piece of conceptual design and assigns it to a specific logical tier of presentation, business, or data level architecture. • Composed of three logical tiers: a user interface tier, a business tier, and a data tier. The following diagram illustrates all three tiers.
User Interface Tier Provides a representation of the system to the user and in the E-commerce example is divided into two sections, the consumer interface and the management interface.
Customer Interface Controlled by functional pieces in the user interface tier that manipulate the user interface available to shoppers. Shoppers browse catalogs, manage their profiles, place orders, and perform other tasks by using the consumer interface of the presentation tier. bb
Management Interface The administrative “back end” of the Web site. This tier is not visible to shoppers, and is accessible only to select management personnel who are responsible for maintaining and updating the site. Two major teams within a business organization (for example, sales/marketing and production) access the management console using a set of management tools to perform specific tasks.
Business Tier • Enables a company to disengage business logic and rules from the data or user interface tiers. • Consists of functional pieces that manipulate data according to business rules. • Facilitates better management of changes in the business that must be implemented at the system level. • Allows components to be written once and reused multiple times to serve multiple clients and purposes.
Data Tier • Captures and preserves data for the system. • Consists of functional pieces for storage and retrieval of information used for the operation of the site. • Independent of the other tiers and makes no assumptions about their existence. • For E-commerce example, includes product descriptions, orders, and useful shopper profile information.
E-commerce Logical Roles • Presentation role. The presentation role consists of the business tier components (which encapsulate the logic from the business tier), the content, and the images required to serve the storefront pages to customers. • Membership role. The membership role authenticates the shoppers as they enter the site. • Search role. The search role hosts the search results page and the search catalogs. • Gatherer role. The gatherer role builds the search catalog. • Management console. The management console hosts the administrative site. • Membership database role. The membership database role is the persistent data store for membership directory and shopper profile information. • Storefront database role. The storefront database role stores product, basket, receipt, and order history data.
Physical Design • Specifies which logical pieces fit into specific physical pieces of architecture. • For e-commerce projects, the physical design should include anticipated metrics to assess the performance goals, uptime goals, and milestones of the solution code to be written.
Presentation Servers The presentation servers combine the logical presentation and business tiers into one physical system. The server itself will be running Microsoft Windows® 2000 Advanced Server and consist of Microsoft Internet Information Server 5.0 (IIS) and Site Server Commerce Edition 3.0. These presentation servers will be connected via 100-megabyte (MB) Ethernet to a Microsoft SQL Server™ 7.0 database.
Database Servers The database servers provide and capture data for the Web site using SQL Server 7.0 and clustering services. These servers reside as stand-alone, high-powered computers and are not part of the Web farm, although they operate on the same network. The Internet Storefront uses an active-active clustering configuration for high availability.
Content Server This server will enable content to be staged and quality assurance (QA) procedures to be checked before moving a site to production server(s). Only team members who must update, edit, and create Web content should be allowed access to this server. Production groups can replicate to the production systems, either on a fixed or on-demand schedule.
Hot Swap Servers The hot swap server is a standby server that can be used to replace a server that fails. Two types of hot swap servers are recommended for the Internet Storefront: a dbHotSwap and presHotSwap. The dbHotSwap can replace a data server that has crashed or been taken offline. The dbHotSwap server can be either a replication client of the online data server or a system that is brought up to speed by applying a tape recovery. The presHotSwap is a standby server that mirrors the structure and configuration of the presentation server. Anytime updates or changes are applied to the presentation server they must also be applied to the presHotSwap servers.
Management Console The management console used for the Internet Storefront is a Windows 2000 Professional workstation that allows system administrators to manage and interact with computers that are part of the site. Site Server Commerce Edition version 3.0 tools must be installed on this management console. For example, the Management Console Workstation (MCW) could be used to capture performance statistics of a presentation server or run Database Consistency Checker (DBCC) on a data server using SQL Server 7.0 Enterprise Manager. Any back-end processes can be initiated from the MCW such as content replication or database backup.
Scalability A Web site can be scaled either horizontally or vertically. You can use either of these methods or a combination of the two depending upon the demands of the site. Horizontal scaling is achieved by adding duplicate servers and bandwidth as needed. Vertical scaling is achieved by adding more power to an existing computer (by adding random access memory {RAM} or DASD, more disk space, or faster input/output {I/O} controllers).
Deployment Scenarios The site’s physical architecture is determined by the amount of traffic expected to visit your particular Web site. The following deployment scenarios represent solutions scaled to three different sizes (entitled classes 1, 2, and 3). This information will provide guidance in planning the physical architecture for your e-commerce solution.
