Page "Software architecture" Paragraph 34

According to the Intension / Locality Hypothesis, the distinction between architectural and detailed design is defined by the Locality Criterion, according to which a statement about software design is non-local ( architectural ) if and only if a program that satisfies it can be expanded into a program which does not.

For example, the client – server style is architectural ( strategic ) because a program that is built on this principle can be expanded into a program which is not client – server ; for example, by adding peer-to-peer nodes.