An object request broker (ORB) for receiving an incoming message including a message header and a message body in General Inter-ORB Protocol (GIOP) type format, the ORB comprising: an external ORB element for converting the header of the incoming message to an implementation-specific format, and for providing the header in implementation-specific format with the body in GIOP type format to a distribution mechanism for identifying an appropriate target server for processing the body of the incoming message; and an internal ORB element associated with the identified target server for converting the body of the incoming message to an implementation-specific format for use by the target server to process the message.