All transport situations transfer 'materials' from a point of production (or storage) to a point of consumption (or storage). 'Materials' could include people accumulating at a bus stop or a departure lounge at an airport. All situations can be represented as a sequence of movements between points, and operations (like loading, unloading, fuelling, or maintenance) at those points.

It is useful to think of the BISLogistics solution in terms of two (or sometime three) layers. The first two layers, Background and Transport are shown in the following diagram (based on the movement of physical goods). The background layer simulates production, consumption and the operation of stockpiles or warehouses. The stockpiles or warehouses may contain bulk solids, liquids or individual items. Each of these stockpiles has a matching production or consumption facility. In the background layer the state of these stockpiles (i.e. the inventory level) is calculated from the rate of production or consumption. This layer will also handle stock replenishment or depletion in a warehouse without considering the details of the transport to or from the warehouse.

The second layer is the transport layer. The interaction between the two layers is shown in the diagram. In this layer the transport mechanisms e.g. trucks, trains, aircraft or vessels, conduct trips that move material from one stockpile to another. Specified resources such as the transport mechanisms, trailers, drivers, loaders, berths, cranes and stevedoring gangs are used for the operation at each 'port of call'. Any shift breaks or breakdowns of these resources will halt the operation. Total durations are calculated from various parameters like distances, speed, set up times, tonnes, and loading and unloading rates. These parameters can also be used to calculate variables such as costs and fuel usage.

An optional third layer is a scheduling layer. This layer will need to be customised for each application so is not part of the general solution. Scheduling can provide a way to optimise an operation. This layer can also contain customised rules to allocate costs to cargoes.

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