  Over the past decades, coordination languages have emerged for the
specification and implementation of interaction protocols for communicating
software components. This class of languages includes Reo, a platform for
compositional construction of connectors. In recent years, various formalisms
for describing the behavior of Reo connectors have come to existence, each of
them serving its own purpose. Naturally, questions about how these models
relate to each other arise. From a theoretical point of view, answers to these
questions provide us with better insight into the fundamentals of Reo, while
from a more practical perspective, these answers broaden the applicability of
Reo's development tools. In this paper, we address one of these questions: we
investigate the equivalence between coloring models and constraint automata,
the two most dominant and practically relevant semantic models of Reo. More
specifically, we define operators that transform one model to the other (and
vice versa), prove their correctness, and show that they distribute over
composition. To ensure that the transformation operators map one-to-one
(instead of many-to-one), we extend coloring models with data constraints.
Though primarily a theoretical contribution, we sketch some potential
applications of our results: the broadening of the applicability of existing
tools for connector verification and animation.
