Introduction and Definitions of Terms

DSI defines an interface for communication between DROPS-components. The main aspects of the interface are

• packet-oriented zero-copy data transport between all parties
• traffic description based on jitter-constrained periodic streams
• QoS-support with nonblocking synchronisation and limiting the validity of data by time
• isolating the communication partners with respect to CPU and memory usage at the communication channel
• support for packet dropping and resynchronization
• blocking synchronisation for non-realtime components
• active data transport, independent of the initiating client application

The usual application scenario includes a sender and a receiver with a connection in between. Because the sender and the receiver often are servers in the DROPS environment, the connection is usualy being setup by the common client of both servers.

DSI defines a component as an active part, which is either the sender or the receiver. The communication endpoint in a component is called a socket. To operate on sockets, the DSI API for components is used.

Contrary to components, an application creates a connection and initiates the data transfer but is not involved in the actual data transport. The connection created by the application is referred to as a stream, the term is only valid in application context.

An application uses component-specific interfaces to trigger the creation of a send- and a receive-socket at the components. Both components return references to their sockets called socket references. Then the application uses the DSI API for client applications to create and operate on the stream.

Architectural Overview

DSI needs an L4-compatible mikrokernel and the L4 Environment to run.