EnterpriseServiceBus

Last edit September 11, 2006
EnterpriseServiceBus (ESB) is a technical infrastructure. It is one mechanism that can be used to assist with the implementation of a ServiceOrientedArchitecture.

See article All aboard! The enterprise service bus pulls in at http://www.zdnet.co.uk/print/?TYPE=story&AT=39162065-39020505t-21000005c (ref A)

A good book for learning about the principles behind ESB is EnterpriseIntegrationPatterns.

ESB and AsyncMessagingLayer

An asynchronous messaging layer (see MessageOrientedMiddleware) differentiates this type of architecture from solutions built on older technologies like InternetInterOrbProtocol (IIOP), DistributedCom (Dcom), etc. Its use promises relief from IDL proliferation problems described in FacadeAtTheDistributionBoundary.

ESB based implementations support a Publish and Subscribe Event handling mechanisms. Typically, the ESB engine has message transformation capabilities so it can assist in the integration of disparate applications. Other characteristics of this ESB based implementation are described in the article, "In Pursuit of Agility", located at http://www.intelligententerprise.com/print_article.jhtml?articleID=49400918. The article is also the source of the following picture.

Players & Approaches

May05 article of the same name lists vendor product approaches at http://www.computerworld.com/softwaretopics/software/appdev/story/0,10801,101699,00.html.

Forrester Research has compared EnterpriseServiceBus to an immature replacement for traditional EnterpriseApplicationIntegration, while others see ESB as a collection of existing resources exposed as services It appears that research organization is seeing ESB as a tactical deployment of architectural components, on the road to the adoption of the slowly maturing ServiceOrientedArchitecture.

From 9Jul04, Forrester write-up at http://news.com.com/Commentary:+Hop+on+the+bus%3F/2030-1069_3-5263159.html -
  • A layer of middleware through which a set of core (reusable) business services are made widely available
  • ServiceOrientedArchitecture can be implemented in other ways, such as message-oriented middleware, CORBA, integration platforms and custom development.
  • Example products include Sonic ESB, SeeBeyond and Webmethods Fabric.
  • "Federated Department Stores" quoted as having built a customized solutions using vendor tools and custom developments to link up various services.
  • As yet (2004), process mapping and support tools are not present or immature, to be awaken with the proliferation of standards such as BusinessProcessExecutionLanguage .

For those who can afford the papers from Forrester Research, check out Anyone got information on how other IT thinktank / consultancy organizations (e.g. GartnerInc, ZapThink) view the relationship amongst EnterpriseServiceBus and ServiceOrientedArchitecture? -- dl

Sameless Plug for Sonic Software

The first ESB was shipped by SonicSoftware in 2002. The company remain a leader in the ESB product space and ESB DavidChappell has often engaged supporters of the MicroSoft WindowsCommunicationFoundation, on how the JavaPlatform based ESB is the better (or equally good) alternative to implementing architectures.

(The previous paragrah is very enthusiastic in its support of Sonic. While Sonic's product may have been the first actually named "Enterprise Service Bus," other MessageOrientedMiddleware products, such as WebSphereMq, have been around much longer and were arguably providing ESB functionality before it was called ESB. Even Sonic's ESB product was largely a repackaging of its existing JavaMessageService product.)

BigBlue and others to offer Bus Services

IbmCorporation will have Jetstream product in WebsphereApplicationServer in late 2004. Its competitor BEA will be offering Quicksilver. The article at http://zdnet.com.com/2100-1104_2-5262604.html also mentions MicrosoftIndigo as a vendor technology fighting for the same market share.

BigBlue might view ServiceOrientedArchitecture implementation as "separate" from EnterpriseServiceBus There has been criticisms leveled at IbmCorporation ExtremeMarketing practices in this area, namely the association of WebSphere V6 with ready made ESB.

In "A Bus by Many Different Names" at http://www.crmbuyer.com/story/ewsZbjDpZr8eb9/A-Bus-by-Many-Different-Names.xhtml, BigBlue was "convinced" to restate that an ESB can be "stitched together" using its products. Major criticisms of the earlier BigBlue viewpoint include the lack of support in "advanced message brokering" and "repository".

BigBlue has an article on how their ESB can provide an EventDrivenArchitecture (an early representation of ComplexEventProcessing) solution, for purposes of meeting ComplexityManagement needs. See Mar06 article at http://www-128.ibm.com/developerworks/webservices/library/ws-soa-eda-esb/index.html#Resources

It appear that an EnterpriseServiceBus compliant set of applications does not have to interact using ExtensibleMarkupLanguage based protocols. The article (ref A) did say that one has to include the 80 percent of applications that are EDI based transactions.

Appears to be primarily a JavaPlatform integration tool

DaveChappell, in a May03 article on JavaBusinessIntegration at http://webservices.sys-con.com/read/39767.htm, said this near the end:
  • "...although this article focuses on J2EE, the ESB is platform agnostic. A good ESB should be capable of supporting direct access through DotNet clients and C++ clients"

MicrosoftIndigo LoveHateRelationship

May05, Dave Chappell of Sonic Software, a major vendor in EnterpriseServiceBus, presented the talk "ESB Myth Busters: 10 Enterprise Service Bus Myths Debunked". It can be seen at http://webservices.sys-con.com/read/48035_1.htm.

Dave is also author of the book EnterpriseServiceBus (ISBN 0596006756) and have "significant differences" with views held by the MicrosoftIndigo camp.
EnterpriseServiceBus and JavaTwoEnterpriseEdition

Probably better described by someone who knows the Java platform well. Meanwhile, you have to settle for links I have found. -- dl
BEA has released their ESB in the form of the AquaLogicServiceBus. It's a server with a web-based tool to do routing, transformation, security, reliability, etc. without code (other than XQuery or XSLT).

See also ComponentBus
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