1. Software Architecture Taxonomy
Jim Fawcett
CSE681 – Software Modeling and Analysis
Summer 2006

2. Agenda Taxonomy – An organization or catalog
Software Architecture Taxonomy:
Distributed System Structures
Other, possibly non-distributed, structures
Discussion of each

3. Distributed Architectures
Client–Server
Client initiates, server responds
Peer-to-Peer
Peers both initiate and respond
Controller-Satellites
Has elements of both client-server and peer-to-peer
Collaborative
Focus on controlled sharing of work products
Service Oriented
Provides a set of fundamental services used as a basis for building applications
Agent-Based
Focus on search and modification using mobile agents
Often thought of as web-crawler, but could be code crawler, test results crawler, …

4. Not Necessarily Distributed Architectures
Event-Driven
System activities are all responses to events
Model-View-Controller
Model manages data
System provides multiple views
Views are constrained to be coherent by controller
Layered
Divided into core services, utilities, user services
Whiteboard model
Users interact in real-time with shared data

5. Client-Server Architecture
Client initiates, server responds
Servers are passive
Only provide replies to specific request types
Server provides a service
Web server, file server, Network Storage
often used to provide access to shared resources
Examples:
Business data management, Web sites

6. Client Server Structure

7. Peer-to-Peer Architecture
Peers both initiate requests and respond to requests
Supports real-time notification
Often based on message-passing
Can support store-and-forward to promote communication reliability
Basis of Controller-Satellite structure
Examples:
Chat, file sharing

8. Peer-to-Peer Structure

10. Controller (Hub)-Satellite
Hub coordinates satellite machines (or their users)
Downloads shared resources appropriate for this time
Manages shared resources
Satellite can contact hub
Upload modified resources, make requests for information
Interact with shared resources
Notify hub of satellite events
Examples:
Grid computing as in

11. Controller-Satellites Structure

12. Controller-Satellites Example Product Service Organization
Hub coordinates employees with satellite machines
Downloads work schedules, orders, routing
Manages shared resources
Product catalogue, specifications
Satellite can contact hub
Upload orders, request parts, request directions
Interact with shared resources
Examine shared calendar, inventory
Notify hub
Service call completion, request parts

13. Controller-Satellites Example

14. Collaborative Server manages shared resources in real-time.
Responsiveness is high priority so users can interact freely through the server.
Data structures used to hold work products are a critical issue due to performance constraints.
Satellite machines provide real-time views of work products.
Archiving and speedy retrieval of work products is an important function of collaborative systems.
Chat facilities are often integrated into the collaboration process.

15. Collaboration Structure

16. Software Collaboration Example Distributed Whiteboard
Server manages shared whiteboard used to display software system architecture and design.
Distributed users collaborate to develop and review architecture and design.
Work products are:
UML diagrams
Code files
Documentation
Satellite machines provide “distributed Visio” like views supporting real-time edits.
Diagrams may be created by remote participants. Documents may be reviewed and edited.
Collaborative hub archives all work products.

17. Software Collaboration Structure

18. Service Oriented Architecture
Applications are built from a rich collection of distributed services.
Services are provided as OS services and Web services.
Programs are mostly glue that bind together services needed for the program’s functionality.
The next Windows, a.k.a. Vista, provides a service architecture through its Indigo component, now known as Windows Communication Foundation (WCF).
Example:
Web Services, COM+

19. Agent-Based Architecture
Program is based on autonomous software agents that:
Are mobile, self-directed entities
Communicate with a hub and perhaps each other
Are often focused on search and retrieval
Run on separate threads
Examples:
Web site indexing, File indexing
Code analysis, Test results analysis
Optimization using Evolutionary Programming strategy
Games

20. Enterprise Computing combines structures
Enterprise computing binds together a business with its partners, suppliers, and customers.
May integrate many functions:
Inventory control, order processing, product disclosure, product design collaboration facilities.
Likely to use a Controller-Satellite structure.
Hubs may act as satellites to a partner’s hub.
Partners work together through a Collaboration subsystem.
Important customers collaborate on custom designs.
May be based on a Web-based Service Oriented Architecture:
Suppliers provide product information and order status information.
Partners provide schedule, status, product information.

21. Project #5 Collaborative? Controller-Satellite? Service Oriented?
Layered?
Agent-based?
Enterprise Computing?

22. End of Presentation