Overall Purpose Simple Digital Library Interoperability Protocol is intended as a lightweight protocol for accessing information resources. It takes the function of search middleware, brokering access to diverse, autonomously-maintained information repositories, with the object of simplifying the task for client application writers who would like to offer access to those resources. The client requests searches over information sources.
Clients initially request searches through the search interface.
The second interface, the result access interface, handles follow-up requests about the results of searches. Results Access Interface Follow-up requests or information about the result set is acquired through this interface. Requests can also be cancelled via this interface. This interface deals with requests about the sub-collections that it serves out. For the documents in a sub-collection, the document properties, and which of the properties are searchable and retrievable are stated.