SID is a software package offering a variety of multicast support for distributed applications.
Functionality includes reliable multicast, global, total ordered multicast, multiRPC, etc.
The package is based on IP multicast and pthreads. Current efforts are in designing a scalable distribution layer for hundreds or thousands of participants over an Internet. In SID, the reliable multicast protocol os based on a positive acknowledgement scheme, while the reliable multicast protocol in SID2 is based on negative acknowledgements.