A three-layer communication architecture for real time applications

The benefits and applicability of a three-layer communication architecture where the application layer is hooked on top of the logical link control (LLC) layer are discussed. It is explained that the use of the manufacturing message standard (MMS) requires a acknowledged LLC services. For implementing these services on a token bus (like MAP) one can use the immediate response option instead of requests with no response on the medium access layer. It is shown that the use of the immediate response option only gives better results for long messages, which may not occur frequently in real-time applications