An Executive Summary

Sean MacRoibeaird
Sun Microsystems XML Technology Center

What is it?

The key item of consideration in the UDDI specifications is the "Web service." A Web service describes specific business functionality exposed by a company, usually through an Internet connection, for the purpose of providing a way for another company or software program to use the service. The UDDI specifications define a way to publish and discover information about Web services. UDDI aims to automate the process of publishing your preferred way of doing business, finding trading partners and have them find you, and interoperate with these trading partners over the Internet.

UDDI Business Registry

UDDI relies upon a distributed registry of businesses and their service descriptions implemented in a common XML format.

The UDDI Business Registry provides an implementation of the UDDI specification. Any company can access the registry on the Internet, enter the description of its business, reach a UDDI site and search through all the business services listed in the UDDI registry. There is no cost to access information in the registry. Though based on XML, the registry can also describe services implemented in HTML. CORBA, or any other type of programming model or language.

Why UDDI?

Most eCommerce-enabling applications and Web services currently in place take divergent paths to connecting buyers, suppliers, marketplaces and service providers. Without large investments in technology infrastructure, businesses of all sizes and types can only transact Internet-based business with global trading partners they have discovered and who have the same applications and Web services.

UDDI aims to address this impediment by specifying a framework which will enable businesses to:

• Discover each other

• Define how they interact over the Internet

• Share information in a global registry that will more rapidly accelerate the global adoption of B2B eCommerce.

Sun's Commitment to UDDI

The UDDI specifications are being developed by a consortium of industry leaders, including Sun Microsystems. Sun has always worked to help establish and support open, standards-based technologies that facilitate the growth of network-based applications. Sun sees UDDI as an important project to establish a registry framework for business-to-business e-commerce. As one of the primary contributors to the development of XML, Sun supports the planned use of this emerging standard as the data foundation for the registry. Sun also applauds the UDDI project's stated intent to have the registry support services integrate with a wide set of existing core Internet technologies, such as Java^TM, Jini^TM, CORBA, ebXML, RMI and HTML.

Technical Overview

UDDI forms a "next layer" in an emerging stack enabling rich Web services. UDDI is a layer on top of standards-based technologies such as TCP/IP, HTTP, XML, and SOAP to form a uniform service description format and service discovery protocol.

Data Types

The core information model used by UDDI registries is defined in an XML Schema which defines four core types of information.

1. Business Entity: Information about the party who publishes information about a service. This is equivalent to White Pages information.

2. Business Service: Descriptive information about a particular family of technical services. This is equivalent to Yellow Pages information. A Business Entity contains business services.

3. Binding Template: Technical Information about a service entry point and construction specifications. This is equivalent to Green Pages information. A business service contains binding templates.

4. tModels : Descriptions of specifications for services or taxonomies. These form the basis for technical fingerprints. Binding template data contains references to tModels. These references designate the interface specifications for a service.

Programmer's API

The UDDI specifications define Web service interfaces to allow programmatic access to the UDDI registry information. The UDDI API is based on SOAP (Simple Object Access Protocol) which provides a synchronous RPC mechanism to UDDI. All UDDI registry Operator sites will support all the UDDI API calls. The UDDI API is divided into two logical parts:

1. Inquiry API: Provide programs with the capability to locate candidate businesses, Web services and then services, and drill into the specifics based on overview information provided in the initial calls. The Inquiry API functions are exposed as SOAP messages over HTTP. No authentication is required to make use of the Inquiry API functions.

2. Publisher API: Enables programs to save and delete each of four data types supported by UDDI. Authenticated access is required to use the Publisher API, i.e. the user must first sign-up with one or more operator sites to establish user credentials.