  Service virtualisation is a supporting tool for DevOps to generate
interactive service models of dependency systems on which a system-under-test
relies. These service models allow applications under development to be
continuously tested against production-like conditions. Generating these
virtual service models requires expert knowledge of the service protocol, which
may not always be available. However, service models may be generated
automatically from network traces. Previous work has used the Needleman-Wunsch
algorithm to select a response from the service model to play back for a live
request. We propose an extension of the Needleman-Wunsch algorithm, which uses
entropy analysis to automatically detect the critical matching fields for
selecting a response. Empirical tests against four enterprise protocols
demonstrate that entropy weighted matching can improve response accuracy.
