Performance measurement of data transfer services in MAP

The emergence of the enhanced performance architecture, which provides the application process with direct access to a fast datalink datagram service provided by the full MAP (manufacturing automation protocol), is discussed. An explanation is given of the functional differences between the two service types and why both are useful in the manufacturing environment. It is shown that message segmentation makes a substantial contribution to overall message latency. The effect of retransmission timer setting and the maximum credit window size is illustrated. Throughput and end-to-end delay for one implementation of MAP are reported, and conclusions are drawn about the expected performance cost of messages sent as datagrams versus messages sent over virtual circuits.<>