In recent months there has been a flurry of activity in the domain of Web Services choreography languages. This has been accompanied by a lot noise and hyperbole, including predictions that such languages will destroy ebXML.

Such dire predictions are made in the vacuum of ignorance: ignorance of what ebXML is, especially the Business Process Specification Schema (BPSS), and ignorance of how ebXML and Web Services differ.

In this presentation, I will attempt to cast some light on these areas of unfamiliarity. We will explore what ebXML is (particularly the BPSS), Similarly, we will examine Web Services, especially choreography languages such as the Business Process Execution Language for Web Services (BPEL4WS). Finally, we will compare what types of applications these two distinct technology suites are suited for.

Areas to be highlighted will include:

- Messaging model and features

- Business protocol models

- Security

- Quality of service (Reliability)

- Trading partner agreements

- Integration with back-end systems.

- Business-oriented features (non-repudiation of receipt etc.)

The major conclusions will be:

- ebXML is designed for peer-to-peer electronic communications between businesses, with a large suite of security and quality-of-service features that business require to safely conduct commerce over the internet. It was designed from the top down to accomplish this.

- WS is, by contrast, as set of specifications that are designed in a bottom-up fashion to provide a general-purpose technology base for interoperable messaging systems using networks, possibly including the internet. Business-mandated features like security, quality-of-service must be provided by applications, or by yet-to-be-defined specifications that are structured as loosely-coupled aspects of the messaging system.

- WS is a general-purpose technology platform, whereas ebXML is a purpose-built business messaging system. In the fullness of time, and with enough WS- specifications, it should be possible to implement ebXML support (or something very much like it) using WS technologies.