On IRIX systems, MPI automatically detects multiple HIPPI network adapters and uses as many of them as possible when sending messages among hosts. The multiboard feature uses a "round robin" selection scheme in choosing the next available adapter over which to send the current message. The message is sent entirely over one adapter.

During the initialization of the MPI job, each detected adapter is tested to determine which hosts it can reach. It is then added to the list of available adapters for messages among the reachable hosts.

By means of the multiboard feature, messages are sent over as many HIPPI network adapters as are available between any pair of hosts.

The multiboard feature is enabled by default and relaxes the requirements of earlier MPI releases that the HIPPI interface adapters be located in the same board slot and have the same interface number, such as hip0. A series of new environment variables with this release allows the user to further specify the desired network connection.