More definitions…
The Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH) provides an interoperability framework for metadata harvesting.
A data provider is a source repository of e-print metadata records. A service provider harvests those records using the OAI-PMH.
Notes:
Each record in an OAI compliant repository is assigned a unique identifier, and the protocol uses this to identify and extract the metadata from the item.