You can create a Substitution relationship between any two Classifiers in SysML. A Substitution is a relationship between two Classifiers which signifies that the substitutingClassifier complies with the contract specified by the contract Classifier.
This implies that instances of the substitutingClassifier are runtime substitutable where instances of the contract Classifier are expected. Substitution, unlike specialization, does not imply inheritance of structure, but only compliance of publicly available contracts.
Substitution requires:
•Interfaces implemented by the contract Classifier are also implemented by the substitutingClassifier or else the substitutingClassifier implements a more specialized Interface type.
•Any Port owned by the contract Classifier has a matching Port owned by the substitutingClassifier.
Relates
The Substitution relationship can be drawn like this:
