Structural design that defines a computer network’s general characteristics as well as its precise mechanisms. In broad terms, a computer network can have open or closed architecture. Open architectures allow the system to be connected easily to devices and programs made by other manufacturers. Open architectures use off-the-shelf components and conform to approved standards (see open systems environment). A system with a closed architecture, on the other hand, is one whose design is proprietary, making it difficult to connect the system to other systems. For both open and closed architectures, the client/server or peer-topeer architecture defines the precise mechanisms by which computer network elements are tied together, as described below: