Mary Shaw and David Garlan state that connectors are "the loci of relations among
components. They mediate interactions but are not things to be hooked up (rather,
they do the hooking up). Each connector has a protocol specification that defines
its properties, which include rules about the types of interfaces it is able to
mediate for, assurances about properties of the interaction, rules about the order
in which things happen, and commitments about the interaction (...).''