This type of nodes simulates resources used by the entities represented by the messages. A real value, called the node capacity, is associated to the node. The messages in the EL represent entities that demand a certain quantity of that capacity during a certain time. The EL is examined and, for each message, it is checked if the demanded quantity is available. If it is so, the message is moved to the IL, the time of future depart is scheduled in the FEL, and the quantity of resource used for the message is subtracted to the available capacity. If there is not enough capacity, the message remains in the EL. When the departing event is executed, the message is removed from the IL and sent to the successor nodes. So, the node has two function an accepting function that assigns resource to a message and put it in the IL and a departing function that extracts the message of the IL and frees resource.