I've had a bit of a graphic spurt (as it were) and so here's another blog post based around a diagram.

I was talking to a journalist a couple of weeks back about the kinds of functionality that customers need to look for when searching for tooling for SOA initiatives, and which vendors provide which groups of functionality. It's not always easy to explain this kind of thing over the phone, so I thought I'd have a go at describing the main areas of functionality as a pyramid. Something like this:

In our assessments of SOA tool vendors' capabilities (see here for an example) we highlight nine separate areas of functionality, but this is a simpler picture that just focuses on four:

• Service enablement—this is functionality that helps you take existing IT assets (applications, databases, etc) and create service interfaces based on the capabilities they offer. A lot of vendors provide facilities in this area because in truth most of them started out as integration tools vendors.
• Orchestration and composition—this is functionality that helps you aggregate services and create "composite services" or "processes". Most vendors offer some capability along these lines, and most involve the ill-named "BPEL" in some way (but that's another story). The reason is the same as the reason above: many of the SOA tooling vendors had "pre-SOA" offerings which allowed you to aggregate and orchestrate resources from existing applications and systems.
• Lifecycle management—this is all about supporting development, integration and operations teams in linking their efforts to ensure that the consumer service experience is high-quality and consistent under potentially unpredictable circumstances. Typically the foundation of this capability is some kind of registry/repository, but ideally tools go further than this—firstly by helping to automate team workflows for implementing quality controls at design time; and secondly by helping to translate design intentions relating to operational SLAs into runtime policies which are tied into the infrastructure. Some vendors are starting to offer capabilities in this area, through acquisition (HP/Mercury/Systinet, webMethods/Infravio, BEA/Flashline (kind of)); OEM/resale agreements (Oracle/Systinet, BEA/Systinet) or in-house development (IBM, Sun).
• Service development—this is about the ability to design services "from scratch", or to design services where any existing applications/systems offer functionality which only partially fulfils a requirement. Ideally this starts "contract first"—first of all documenting what the service needs to do and the commitments the provider should make to service consumers; and only then refining that spec into a working service implementation and interface.

Most SOA tools vendors suck at this last bit, frankly. I think that TIBCO is starting to do provide some interesting supporting facilities for this broad area with ActiveMatrix, and as vendors start to implement SCA/SDO in their tools the situation might get better across the board. In the meantime if you've heard of a vendor targeting SOA specifically that really provides solid tools to help with this kind of contract first" development approach, I'd love to know.