3. Logical path

A logical path is a path between two end stations, made up of physical paths and intermediate equipment (figure 11 ). In this paragraph, we introduce some of this equipment to show that delays in networks are due not only to transmission and propagation, but also to intermediate storage, processing in intermediate stations, etc. We assume here that throughputs are identical on all physical paths, and that the same applies to all logical paths. We assume here that data rates are identical on all physical paths, and that the same applies to propagation speeds.