Fault-tolerant system-to-system communications system and method

Abstract

A tiered communications service which utilizes multiple methods of communication and provides the ability for different host computer systems to pass dam, unconcerned with the type of communications medium used by the service. Each method of communication is ranked according to its preference within the service. When the communications service encounters an error while attempting to send data to another host system, it performs an automatic switch to the method with the next lower preference which is available for use. The service sends notification to the other system of the change in communications method used and which method to start using, then continues sending the data. The communications method may be switched to a higher or lower preferred method explicitly by operator command, which also sends notification to the other systems of a change in method. Each host system has the ability to communicate with other host systems via various communications methods, depending on the methods defined to the service. A host system can communicate with a second host system using one communications method and communicate with a third host computer system using a different communications method. To communicate between any two host systems, the service utilizes the highest preferred common communications method available for use, except when changed by operator command.