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Friday, October 22, 2004 The AToM Splits Definition The AToM, Anne Thomas Manes, took the time to mark up some definitions of SOA. I love it. Four things I'd change: 1. Services don't have to be 'autonomous' 2. Services don't have to be used for 'business' 3. In many cases services shouldn't be designed for 'reuse' 4. In many cases services won't be 'discovered' Thus, try not to use those four words in the definition. Posted on the soa news group... =============================================== SearchWebServices asked this group of people to provide 50 word descriptions of SOA. It's very hard to describe SOA in just 50 words (and obviously some folks ignored the 50 word limit). You simply can't describe the tenets of SOA so succinctly. Burton Group recently published a 22 page report describing SOA, which I think does a much better job than any of these short descriptions. I could easily write an entire book on the topic. In my description, I endeavored to convey two of what I consider to be the three major tenets of SOA: application factoring and abstraction, although I was not able to convey the multiple aspects of these two tenets. I was also not able to convey the third tenet: the requirement for standard protocols for description, discovery, and communication. Please see my comments below bracketed by ::atm::::/atm::. -----Original Message----- From: Gervas Douglas [mailto:gervasdouglas@yahoo.co.uk] Sent: Thursday, October 21, 2004 12:53 PM To: service-orientated-architecture@yahoogroups.com Subject: [service-orientated-architecture] Re: Definition of SOA Here are some definitions provided by SearchWebServices: ::::------------------------------------------------------------------- ------------- "SOA is a framework enabling application functionality to be provided, discovered and consumed as re-usable Web Services sets. While Web Services do not equal SOA, it's one of the enabling standards. SOA abstracts complexity and implementation details, making it an ideal architectural mindset to leverage functionality trapped within mainframe/midrange systems." Scott Rosenbloom is chief strategist with WRQ Inc. ::atm:: SOA is an architecture -- not a framework. It is a style of design -- not a tool. On the other hand, "web services" is a framework -- a set of tools (middleware) to help you implement applications and systems that adhere to SOA design principles. (Although note that building applications using the web services framework does not guarantee SOA.) SOA requires standard protocols for description, discovery, and communication. The web services framework standards define these standard protocols -- XMLSchema/WSDL, UDDI, and SOAP respectively, at a fundamental level, although these core standards are not sufficient to support all SOA requirements (secure, reliable, transacted applications supporting diverse message exchange patterns) -- hence the ongoing effort to develop the WS-* standards. From my perspective, the best way to describe SOA is in terms of design principles. Abstraction is one of the core tenets of SOA -- abstraction between the interface and the implementation, and abstraction between infrastructure and business logic. WSDL facilitates the first, and SOAP facilitates the second. Another core tenet is proper application functionality factoring. What granularity should a service have to best enable reusability? I think this is the most challenging aspect of SOA. My rule of thumb is that a service should represent a business task. But it's hard to quantify this rule. ::/atm:: --------------------------------------------------------------------- ----------- "Secure, integrated delivery of IT solutions meeting business requirements. Solutions must implement, optimize and guide business process execution by combining the functionality of separate, discreet, reusable services. SOA moves away from complex application development, promoting a focus on standardizing interfaces between atomic service components with centralized management and distributed implementation." Dave Morris, I.T. Security Lead TransAlta Corp. ::atm:: For the most part, I don't think this definition helps explain what SOA means, but I like that fact that he associates SOA with "centralized management and distributed implementation". As I said in my response to the first definition, one of the core tenets of SOA is the requirement for abstraction between infrastructure and business logic. Via the separation of the SOAP Header from the SOAP Body, and via the requirements of the SOAP processing model, SOAP enables the clean separation of infrastructure from business logic. It permits developers to externalize most, if not all, infrastructure functionality to the middleware. This feature enables centralized management of the distributed implementation. ::/atm:: --------------------------------------------------------------------- ----------- "The SOA models the business as a collection of self-contained services that are available across the enterprise that can be evoked through standard protocols both internally and externally." Dave McComb, president, Semantic Arts ::atm:: An accurate description, but it doesn't give you any real information to work with. ::/atm:: --------------------------------------------------------------------- ----------- "Service Oriented Architecture is nothing but business oriented architecture, which allows the flexibility of business applications, to become independent but collaborative, while providing their services. The applications under this architecture are both 'client' and 'server' at the same time with freely available services." Satheesan Kunnel, USWWI ::atm:: While it's definitely a brilliant idea to align IT with business, I don't think this definition helps you figure out how to do so. ::/atm:: --------------------------------------------------------------------- ----------- "A service oriented architecture is an approach to design and integrate software in a modular method where each module is precisely a 'loosely coupled service' that is accessible over a network and has the capability of being dynamically integrated with other services at run time. A service must present a standard Interface (be it WSDL today) for its functionality and invocation methods while the real implementation of the service is not a concern of an SOA." Rajesh Dawar ::atm:: I like this definition, although I'd like to see a little more definition of what a "precisely" loosely coupled service is. From my perspective, the standard communication protocol has equal importance to the standard description protocol, although this definition obviously gives more weight to the description language. I also view XML Schema as equal weight to WSDL. Again note that SOA does not require XML Schema, WSDL, and SOAP specifically, but it does require that applications rely on a set of standard protocols. When using web services to implement SOA, those standard protocols are XML Schema, WSDL, and SOAP. ::/atm:: --------------------------------------------------------------------- ----------- "Services provide something of value to those who know how to request and consume them, without having to know how to produce that value. SOA is an approach to building software applications as collections of autonomous services that interact without regard to each other's platform, data structures, or internal algorithms." Michael Champion, R&D specialist, Software AG ::atm:: Excellent short description! ::/atm:: --------------------------------------------------------------------- ----------- "A pattern of design, development, deployment, and management of (a) applications and (b) software infrastructure and frameworks in which: Applications are organized into business units of work (services) that are (typically) network accessible Service interface definitions are first-class development artifacts Quality of service (QoS) characteristics (security, transactions, performance, etc.) are explicitly identified at design time Software infrastructure takes active responsibility for managing QoS and enforcing policy for service access and execution Services and their metadata are cataloged in a repository Protocols and structures within the architecture are, optionally, based on industry standards (e.g., the emerging SOAP stack of standards) Randy Heffner, vice president, Forrester Research Inc. ::atm:: I have to question Randy's requirement that QoS characteristics must be explicitly identified at design time. Perhaps he's talking about composite application design time? -- the time when you are assembling services? But even here I disagree. I contend that one of the most brilliant features of SOAP and the web services framework is that it permits you to externalize QoS functionality from the application so that it does not need to be defined at service design time. Instead these requirements can and should be specified at configuration time. QoS functionality can be externalized from the application, specified via policies, and enforced through the middleware. This is a required feature for reusability. The security, reliability, transaction, and performance requirements of a service may vary depending on how it is used in a particular composite application or based on the specific client invoking the service. Rather than hard-coding this complex functionality in the application, you can configure the functionality using deployment and configuration wizards -- just tick the box to add security and reliability functionality. This configuration process should generate a policy description (e.g., WS-Policy), which becomes part of the overall metadata/description contract of the service (consisting of XML Schema, WSDL, WS-Policy, and potentially other description languages). Almost no one is using WS-Policy today, and I view it as one of the most critical holes in the current web services framework. ::/atm:: --------------------------------------------------------------------- ----------- "SOA is a style of design that strives to enable easy integration and flexible applications. In SOA, application functionality is designed as shared reusable services. A service is a piece of application functionality that exposes its functionality through an abstract interface, which hides the inner workings of the service implementation." Anne Thomas Manes, analyst, Burton Group --------------------------------------------------------------------- ----------- "An SOA is an enterprise-scale architecture (typically spanning multiple applications within an enterprise or across multiple enterprises) where the primary structuring element is a service (as opposed to modules, systems, applications or components). A service is a set of related business functions that are interacted with locally or remotely using a message-passing/document-oriented communication style. A service is composed of (1) a (functional) service interface and (2) a service implementation that implements one or more service interfaces and adheres to a certain set of (non- functional) capabilities. Specific services are defined in terms of the transport/application/messaging protocol, not in terms of a specific programming model. An SOA will typically include technical services to manage metadata about service interfaces and implementations, service providers and service consumers; and services for managing and enforcing policies, access control, security features, and transactions, although all of these are optional within any specific SOA instance." Stefan Tilkov, CEO, innoQ ::atm:: Excellent description! (although Stefan obviously exceeded the 50 word maximum) ::/atm:: --------------------------------------------------------------------- ----------- "Service-oriented architecture is an architectural discipline that centers on the notion that IT assets are described and exposed as Services. These Services can then be composed in a loosely-coupled fashion into higher-level business processes, which providing business agility in the face of IT heterogeneity." Ronald Schmelzer, analyst, ZapThink LLC ::atm:: Excellent description! ::/atm:: --------------------------------------------------------------------- ----------- "Service Oriented Architecture (SOA) is an approach to the development of loosely coupled, protocol-independent distributed applications composed from well-defined, self-contained software resources accessible as Services across the extended enterprise in a standardized way, enhancing re-usability and interoperability." Ankur Gupta, marketing manager, Fiorano Software Inc. ::atm:: Good description, although hard to parse. ::/atm:: posted by jeff | 10:25 AM Wednesday, October 20, 2004 The State of SOA - Quick Summary Here's a quick summary of what I've seen recently in the SOA space: 1. Styles A. HTTP / XML-RPC / AddToCart *** xml over http B. HTTP / Post / Cart/Add *** REST Rules!! C. AnyTransport / SOAP WS-Hdr / AddToCart *** SOAP Rules!! D. AnyTransport / SOAP WS-Hdr / POST / Cart *** SOAP with WS-Transfer Rules!! E. All of the above (we'll use a bump in the network to translate between them) 2. BPEL A. If you can't put J in front of it than it doesn't exist (J-BPEL). You "J" people are so myopic. No, you "X" people insist on doing things the hard way. B. "When I say we support BPEL, what I mean is that we support X/Lang." C. "So, the really powerful part about BPEL is Abstract Processes... What??? Is that why none of the vendors did an implementation???" 3. Vendors A. Our CTO quit and then the team working on the ESB quit; other than that we're on schedule. B. Startups: We have a better product!! So what - we have customers, and have already hit 10 million in revenue - go suck an egg. C. Oh shit, this web service thing is for real. Let's go acquire someone with our devalued stock. 4. Analysts A. ZapThink said "blah blah blah"... A recent report from ZapThink stated, "blah blah blah" and the market size is going to be "blah blah blah". B. All others said, " ". 5. Consultants A. "Yippee!!!" B. "If we keep changing the specs, perhaps the offshore people won't be able to keep up!" 6. Offshore People A. "Yippee!!" B. "If they keep changing the specs, there is no way the customer can afford to keep using the onshore guys!" 7. Grids A. Who cares about service oriented; it is about 'resource oriented'. B. IBM: "A grid is a device whereby our consultants bill you on a regular basis; hence the billing is - on demand." 8. Fortune 500 A. "We're going to have a meeting to discus our SO [fill in blank]." B. "The budget around our SO [fill in blank] looks good for 2005. C. "Let's tell our big vendors that lost all their people to acquire some of these little guys, then convince the offshore contractors to team up with onshore consultants while partnering with the merged ISV's; I'm sure that will work out..." All good fun. posted by jeff | 8:58 AM Sunday, October 17, 2004 What scares you? Does this Burger King commercial scare you?  It should - it's freaky!!! Well - this is why people like web services... you see, that Big ugly king is the VENDOR. And that guy that is scared shitless - that is you. So you're wondering why the BIG PLASTIC vendor is in bed with you... right? People are using web services to decouple them from the BIG PLASTIC guys so that they don't have to wake up with them in the morning. Go ahead, put a little distance between you and the KING. :-) Wake up with the King? posted by jeff | 1:12 PM |
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