Model Description

To illustrate multiple action constructs, we choose the model of Figure . In this model an arriving packet is directed to one of the four service centers. The service center is chosen as follows: first, two out of the four queues are randomly chosen. Then the service center which has the smallest queue (from the two chosen) is selected.

In this model there are three types of objects:

1. Poisson Source - this object generates and sends packets to the split object.
2. Split - this object randomly selects two out of the four queues and sends a message to them informing that there is a new packet to be served. Note also that we tagged one of the two chosen queues with the same probability. This is used in case the queues have identical sizes.
3. Queues - There are four queues that store and serve the packets. The service centers that receive a message from the split node also exchange control messages to determine which one has the smallest queue. Note that the ``data'' sent by the split node indicates the center that must start the comparison process.

Figure: The Multiple Action Model.

The description of the objects is shown in Figures , and .

Figure: The Poisson Source object (Multiple Action Model).

Figure: The Split object (Multiple Action Model).

Figure: The Queue object (Multiple Action Model).