Computer networks are becoming larger not only in the number of nodes connected but also in the geographic area spanned. In addition, networks are becoming more diverse in the variety of equipment from which the network is implemented. This report provides an introduction to the concept of a heterogeneous computing environment. It characterizes heterogeneous computing environments from the point of view of the generic services provided. Standards are necessary in order to implement heterogeneous computing environments. The report provides an introduction by example to the types of technical standards that are necessary in a heterogeneous computing environment and illustrates how such standards can be used to provide services.