Resolution: The maximum size for a TipcMsg is the addressable memory of the client less a few hundred bytes for overhead. Remember that the client_max_buffer in RTserver for each RTclient connection is by default 10MB. If a client creates and publishes a message greater that the default client_max_buffer to the receiving RTserver that RTserver will disconnect the RTclient and discard the contents of the outbound buffer to that client, therefore the message will be lost unless it is using GMD.