With all the web services and SOA terms flying around, it’s hard to keep the functions and layers straight. At the Web Services on Wall Street show last week, Hugh Grant, from Credit Suisse global IT research and development, gave a presentation that I wished my telephony friends could see.

In particular, he gave a quick overview of enterprise SOA architecture that clearly showed how all this stuff goes together. I’ve recreated it here:

• The top layer is the mashup layer, and for you OSI guys – it’s the presentation layer. It aggregates and presents information supplied in the layers below it. This aggregation is normally done through rich internet applications (RIA) such as Microsoft Silverlight or Adobe Flex. Mashup tools such as JackBe and Openscape provide graphical and scripting tools tools to present information as web pages. IBM’s QEDWiki is a collaborative tool that provides document centric views, or you can just be plain old-fashioned and use PHP, Ruby or Java to create a web application.
• The middle layer provides governance, business rules and workflow orchestration for the enterprise. Essentially, this layer makes sure that resources are used by appropriate people in an appropriate manner, and runs business processes for the company such as order management, supply notifications and risk triggers. For financial and health care concerns, this is a big deal, as there are many securities and HIPA regulations that must be followed. IBM, BEA, Sun and Actional from Proress Software all provide governance and workflow solutions.
• The lowest layer consists of the many data and functional services available to the enterprise. For instance, for a wall street firm, one data service may be a constant flow of orders made on the stock exchanges, or it may be an on demand service that calculates the current risk profile of a fund or position. For health care companies, it may be a database of all of the procedures performed on a patient by a department. Sometimes these services are actually delivered over the Internet and are provided by vendors such as Strike Iron or Xignite. Mashery began by turning this around: they allow enterprises to share there internal services to other entities outside the firewall.

So, where does voice fit in here? Primarily at the bottom level. Voice services are published as a service to be used in the layers above it. Access to these services is monitored and guarded by the governance layer; the services are invoked by either business rules, workflow orchestration or by mashups in the top layer. Typical voice services include meet me dialing, click to call, conferencing, outbound messaging and VoiceXML services. Who are the players here? I’ll go over them in depth later, but here’s the important list:

• Platform Offerings : Blue Note Networks, LignUp, Iperia and the 800 lb gorilla, Avaya
• Hosted Offerings : British Telecom, Orange and Vodafone