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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.
Three Tier Architecture
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.
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User Interface Elements
Sample Customer Interface
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.
Business Tier Elements
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.
Data Tier Elements
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 ondemand 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.
Class 1 Deployment
Class 2 Deployment
Class 3 Deployment
Questions?