The Scheduling Open Service Interface Definition (OSID) is an O.K.I. specification. OSIDs are programmatic interfaces which comprise a Service Oriented Architecture for designing and building reusable and interoperable software.

The Scheduling OSID provides a means of associating Agents

Agent Open Service Interface Definition

The Agent Open Service Interface Definition is an O.K.I. specification which supports the creation, retrieval and deletion of Agent and Groups...

 with specific activities (ScheduleItems). This OSID provides a way for an application to integrate

Enterprise application integration

Enterprise Application Integration is defined as the use of software and computer systems architectural principles to integrate a set of enterprise computer applications.- Overview :...

 or use an external calendaring system. In this way, an application can provide calendaring functionality while still allowing integration with an existing Enterprise calendar system, such as one based on CalDAV

CalDAV

Calendaring Extensions to WebDAV, or CalDAV, is an Internet standard allowing a client to access scheduling information on a remote server. It extends WebDAV specification and uses iCalendar format for the data. The protocol is defined by RFC 4791...

, for example.