The most common terms used for brokers these days are repository and registry. Often, these terms are used interchangeably, as general terms referring to the concept of a service broker from all points of view. However, they are increasingly being used to indicate distinct roles. The difference is as follows:
Repositories manage services and their artifacts from a business point of view. That is, they manage interfaces, contracts, SLAs, dependencies, etc. to help to identify, design, and develop services. From a business point of view, a repository should contain all the information about the behavior and interface of a service. This information should be independent from technical details and infrastructure aspects. That is, it should not be necessary to change the repository when a company switches to a new infrastructure (ESB).
Registries manage services from a technical point of view. That is, they manage interfaces, but not all of the contract details: they manage all the technical details necessary to use a service at runtime (i.e., deployment information) and might be used to route service calls to different systems that provide corresponding services. A registry, if necessary, can be part of the infrastructure (ESB).
Both repositories and registries might exist in a SOA landscape. One system might even be used for both purposes. This case, however, raises the danger of making the repository dependent on the infrastructure, which means changing ...