Describe about the Environmental model

It indicates environment in which system exists. Any small or big system is a sub-system of a larger system. For illustration, if software is developed for a college, then college would be part of University. If it's developed for University, University will be part of national educational system. Hence, when model of the system is made these external interfaces are defined. These interfaces reflect system's relationship with external universe (known as environment). Environment of a college system is demonstrated in figure below.