# Universal Description, Discovery, and Integration (UDDI)

Universal Description, Discovery, and Integration (UDDI) specification defines a way to publish and discover information about Web services.

UDDI has two functions:

- It is a SOAP-based protocol that defines how clients communicate with UDDI registries.
- It is a particular set of global replicated registries.

UDDI includes an XML schema for SOAP messages that defines a set of documents to describe business and services information, a common set of APIs for querying and publishing information to the directories, and an API for replicating directory entries between peer UDDI nodes.

For more information on UDDI refer to www.uddi.org

#### UDDI registries

UDDI manages the discovery of Web services by relying on a distributed registry of businesses and their service descriptions implemented in a common XML format. Before you can publish your business entity and Web service to a public registry, you must first register your business entity with a UDDI registry.

UDDI registries come in two forms: public and private. Both types comply to the same specifications. A private registry enables you to publish and test your internal e-business applications in a secure, private environment.

A public registry is a collection of peer directories that contain information about businesses and services. It locates services that are registered at one of its peer nodes and facilitates the discovery of published Web services. Data is replicated at each of the registries on a regular basis. This ensures consistency in service description formats and makes it easy to track changes as they occur. IBM® maintains two public registries called the IBM UDDI Business Registry and the IBM UDDI Test Registry. The IBM UDDI Test Registry allows you to develop your Web service and experience the UDDI registration process without placing your Web service in an official registry. Use the IBM UDDI Test Registry to experiment with UDDI, and to test and validate your Web service. For more information on the IBM's public registries, refer to http://uddi.ibm.com For a list of public registries, refer to http://www.uddi.org/register.html

A private registry allows you to publish and test your internal applications in a secure, private environment.

The UDDI Business Registry acts as a B2B directory linking marketplaces, buyers, and sellers. The information provided in the registry consists of three components: white pages, yellow pages, and green pages. White pages include the business name, contact information, and a text description of the business's services. Yellow pages include industrial categorizations based on standard taxonomies such as NAICS, ISO 3166, and UNSPSC. Green pages include references to specifications for Web services and pointers to various file and URL-based discovery mechanisms. This makes it easy for businesses to integrate across marketplaces. Because it is registered, information is made available across all applications. For more information on NAICS refer to www.naics.com For more information on UNSPSC refer to www.unspsc.org For more information on ISO 3166 refer to http://www.iso.org/iso/en/prods-services/iso3166ma/index.html

Businesses populate the registry with descriptions of the services that they support. UDDI assigns a unique identifier to each service description and business registration. These become the service and business keys respectively. Search engines, and applications query the registry to discover services. UDDI servers are a directory of available services and service providers.

Related Concepts
Web services development
Relationship between UDDI and WSDL
Relationship between UDDI and WSIL
Related Tasks
Publishing Web services and business entities
Related Reference
Data structure types (UDDI registry)