Pragmatic General Multicast (PGM) is a reliable multicast transport protocol. It runs on IP with protocol number 113. The API provided to the applications which wants to use PGM is the standard BSD sockets interface.
PGM can be used by applications for transferring a file from one host to a set of hosts that have joined the multicast group. It can be used to reduce the distribution time of the data and to reduce the load on the distributor.
To use PGM, the underlying network should be multicast enabled.