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Slide 1: Service Oriented Architecture SOA Workshop Starter Kit Service Identification Framework Last Updated: July, 2006
Slide 2: SOA Workshop Starter Kit – Service Identification Framework SOA Workshop Starter Kit Sponsor: Last Updated: Version: Intent of Section: David L. Nichols July, 2006 2.0 This document provides a methodology for identifying services within the context of a Service Oriented Architecture For internal and external use (Unless otherwise documented) 5 – Service Identification Framework V064.ppt 10/7/05 https://kx.accenture.com/_layouts/kx/dispcontributionf orm.aspx?listitemid=71806&listid=Contributions https://technology.accenture.com/SOA Intended Audience: Master Document: To Find Additional SOA content: Copyright © 2006 Accenture All Rights Reserved. SOA Workshop – V2.0 2
Slide 3: Contents • Service Identification Framework Copyright © 2006 Accenture All Rights Reserved. SOA Workshop – V2.0 3
Slide 4: Service Identification Framework Service Identification Framework (SIF) is a methodology based on best practices and real-life experiences identifying services • • • • • • • • • SIF Characteristics Structured approach for identifying services Follows our EA business driven approach Focuses on business services Enabled by underlying IT/ infrastructure services Based on best practices Includes realization planning considerations Structured according to Business Domain and service hierarchy Provides granularity considerations SOA Workshop – V2.0 4 Copyright © 2006 Accenture All Rights Reserved.
Slide 5: Service Identification Framework To achieve the best results during Service Identification a combined approach is needed, that takes into account both business and technical requirements. It should also combine a top-down and bottom-up approach as much as possible Business Requirements Business Architecture Organization and Governance Business Process Architecture Service Identification Framework Service Identification Service Definition Service Implementation Technical Requirements Technical Architecture Information & Application Architecture Infrastructure Copyright © 2006 Accenture All Rights Reserved. SOA Workshop – V2.0 5
Slide 6: Service Oriented Architecture Services and the SOA Framework Business processes: Encapsulate a sequence of steps or activities needed to perform a specific business function. Business processes use business services to provide some business functionality Business Services: A service that is exposed to consumers. This service often serves as a controller/manager of other services such as component services. Business services correspond to a real world activity and recognizable business function such as ‘CreateCustomer’, ‘ProcessOrder’, etc. Component Services: An internal service that is not always exposed to consumers but is exposed and called by business services. An example of a component service can be ‘SubmitCustomerInfo’, ‘RetrieveCustomerInfo’, etc. Application* & Infrastructure Services*: Infrastructure Services provide core lower level services that are not specific to a particular business function or solution. Application Services relate to exposed application functionality. * A.k.a. Technical Services Copyright © 2006 Accenture All Rights Reserved. SOA Workshop – V2.0 6 Business Processes Business Services Component Services Application & Infrastructure Services
Slide 7: Service Oriented Architecture Services and the SOA Framework - Example Business Processes Process Customer Order Validate Order Business Services Check Stock Source from Stock Produce Good Update Stock Source Order Deliver Order Source Order Component Services Source Raw Materials VerifyCredentials() Reserve() Schedule Production Procure() Schedule() Update Stock UpdateInventory() Application & Infrastructure Services Security Raw Materials Workshop Scheduling SAP Adapter LDAP Copyright © 2006 Accenture All Rights Reserved. Factory Mainframe SOA Workshop – V2.0 SAP 7
Slide 8: Top-down vs. Bottom-up Service Identification can be done in both a Top/Down and Bottom/Up approach. Each approach has limitations and risks Top/Down Identify Business Processes Identify Services within Processes Identify Component Services Link Components to Application Services Implement Services Bottom/Up Analyze existing applications Identify patterns in current usage Group patterns in services Document service functionality Expose documented services via generic interface Risks Little focus on business needs Service granularity relatively low Proliferation of small, invaluable services can lead to performance problems SOA Workshop – V2.0 8 Time consuming Little focus on reuse of existing IT Services often too specific for reuse Copyright © 2006 Accenture All Rights Reserved.
Slide 9: SIF Methodology Input: Technical Requirements Analysis • • Technical Requirements Analysis can also leverage the EA framework Can leverage the ARM (Architecture Reference Model) to help create a services model Architecture Reference Model Business Processes (Logic) Business Services (Logic) Execution Environment Application Services Interaction Services Component Services Application Services Profile Services Profile Services Common Services Common Services Data Representation Data Representation Services Services Workflow Workflow Services Services Session Session Services Services Application Base Application Base Services Services Application Application Application Security Services Security Services Security Services Integration Services Backend Backend Integration Integration Message Message Delivery Delivery Services Services SOA Services SOA Services Transaction Transaction Services Services Application Interaction (UI) Service Integration (Integration) Technical Requirements Technical Architecture Information & Application Architecture Infrastructure User Interface Services User Interface Services Interaction Support Interaction Support Services Services Media System Services Media System Services Data Stores Data Stores Data Services Data Services Infrastructure Services Front -facing Environment Front -facing Environment Services Services Services Services Operating System Operating System Infrastructure Platform Performance & Availability Performance & Availability Services Services Infrastructure Security Infrastructure Security Services Services Network Directory Services Network Directory Services Hardware Hardware Network Network Storage Storage Copyright © 2006 Accenture All Rights Reserved. SOA Workshop – V2.0 9
Slide 10: Service Identification • Business Point of View: • • • • Identify Business Domains Identify Business Processes Identify Common Functionality Identify Business Services Technical Point of View: • • • Analyze Existing Applications Identify Application Patterns Identify Component Services Service Identification Identify Business Domains Identify Business Processes Identify Common Functionality Identify Business Services Service Definition Analyse Existing Applications Identify Application Patterns Identify Component Services NB. Service Identification is an interactive and iterative process, ie. each step should contain review and sign-off tasks to ensure the creation of the right services. Copyright © 2006 Accenture All Rights Reserved. SOA Workshop – V2.0 10
Slide 11: Service Identification Business Perspective Business Requirements Business Architecture Organisation and Governance Business Process Architecture Service Identification Identify Business Domains Identify Business Processes Identify Common Functionality Identify Business Services Service Definition Analyse Existing Applications Identify Application Patterns Identify Component Services Copyright © 2006 Accenture All Rights Reserved. SOA Workshop – V2.0 11
Slide 12: Service Identification Service Identification Identify Business Domains Identify Business Processes Identify Common Functionality Identify Business Services Service Definition Analyse Existing Applications Identify Application Patterns Identify Component Services Technical Requirements Technical Architecture Information & Application Architecture Infrastructure Copyright © 2006 Accenture All Rights Reserved. SOA Workshop – V2.0 12
Slide 13: Service Definition • • • • Breakdown required Business Service into Component Services Identify opportunities for reusing Existing Component Services If required Define New Component Services Combine findings into Business Service Definition Service Definition Business Service Requirements Breakdown into Component Services Identify Opportunities for Reuse Service Identification Existing Component Services Define Business Service Service Implementation Define New Component Service Copyright © 2006 Accenture All Rights Reserved. SOA Workshop – V2.0 13
Slide 14: Service Specification • • • • Specify Existing and New Component Services Specify Business Service Specify Service Characteristics Sign-Off Service Identification Service Specification Specify Existing Component Services Service Definition Business Service Definition Specify New Component Services Specify Business Service Specify Service Characteristics Service Sign-Off Copyright © 2006 Accenture All Rights Reserved. SOA Workshop – V2.0 14
Slide 15: Granularity Each tier of the SOA architecture has a different level of granularity. As we move up from the data tier granularity increases, but scalability and performance decreases Application Tier Consumer Application Business Process Components Business Components Business Objects • • Granularity Coarser grained Business Services/Business Process Services • Likely to be coarser grained • Proper for Business Services Likely to be coarser grained • Proper for Component Services (or Business Services) • Too Fine. Internal implementation view • Proper for Application & Infrastructure Services (Technical Services) • Too fine. Stored procedures may be coarser grained • Proper for Application & Infrastructure Services (Technical Services) • + Scalability / Performance Utility Layer Web Services Technical Service Bus (Messaging, JMS, CORBA, “Web Technical Service Bus (Messaging, JMS, CORBA, “Web Services”, etc.) Services”, etc.) Legacy Legacy Applications Applications Directory Enterprise Service Bus (XML Web Services) Enterprise Service Bus (XML Web Services) Publish / Subscribe Service Management Utility Framework Services Data Services Composite Ser vice Composite Ser vice Presentation Layer Solutions I nt ernet Application Layer Web Tier` Web Tier` .NET Applications .NET Applications Composite Ser vice Composite Ser vice Call C ent er CRM CRM ERP ERP HR HR Custom Custom Applications Applications Desktop Platform Desktop Platform Composite Ser vice Composite Ser vice 1 4 7 * 2 5 8 8 3 6 9 # IVR Platf orm IVR Platform Business Process Orchestration Transform ation Adapters Connectivity Composite Ser vice Composite Ser vice Busines s Part ners B2B Gateway B2B Gateway Database - Granularity / Abstraction + Copyright © 2006 Accenture All Rights Reserved. SOA Workshop – V2.0 15
Slide 16: Business Service Granularity How granular should exposed business services be? General Practical Guideline A business service should support a business process within an enterprise and : • expose a common functionality • incorporate a unit of work, • be performed by one entity, • at a single moment in time • in response to a business event • and add value to the business process • service should be reusable • one business function (create Member, etc.) • to prevent excess complexity • service should be stateless • transaction performed when request is received • to explain service creation • This general practical guideline will help to quickly identify some business services for the organization (Pareto Principle or 80/20 rule) • It is important to note that different organizations will make different choices about which services are valuable to them Copyright © 2006 Accenture All Rights Reserved. SOA Workshop – V2.0 16
Slide 17: Fine vs. Coarse Grained The key task of granularity definition is the balance of reusability versus scalability and performance. In general: Fine Grained Follows from analysis of current environment Highly flexible and scalable Overhead per service call relatively high Tight coupling to underlying application logic Lots of small services needed to orchestrate a business process  adds complexity to the user* Can expose underlying implementation details to user Sequencing of operations handled by user Prone to changes in underlying Logic Coarse Grained Follows from business process decomposition Reduced flexibility and scalability Overhead per service call reduced Decoupled from underlying application logic Limited number of services needed to orchestrate business process Sequencing of operations handled within service Less transactions between user and provider Underlying logic and complexity hidden from user Coarse/Fine-Grained definition: refers to the level of complexity of services. A less well-defined level of complexity, such as a purchase order SOA Workshop – a fine-grained level of complexity, such as a simple UNIX call. Copyright © 2006 Accenture All Rights Reserved. that is exchanged between a manufacturer and supplier. Differing fromV2.0 17
Slide 18: Service Identification Guidelines • • • • Consider Quality of Service across the entirety of the service platform and not at component level (Micro service) Understand clearly the business processes When identifying services, use related behavior as the guideline to define the scope of the service Follow SOA Guidelines • • • • • Design the Interface First Design for Service Reusability & Composition Design for Loose Coupling Design for Orchestration Design for Data Representation • • • • Use schemas for data representation Use WS-I profiles when implementing Web services Ensure design for “enterprise consistency”: services that can effectively be reused through out the enterprise Standardization of enterprise business processes and creation of a canonical data model within the Information Architecture can facilitate Enterprise Service design SOA Workshop – V2.0 18 Copyright © 2006 Accenture All Rights Reserved.