Queueing

In some applications, you might want to model a scenario where an entity enters a queue but is willing to wait there for only a certain amount of time. If that time is reached and the entity is still in the queue, then it leaves the queue. For example, a customer arriving at a bank on his lunch hour might be willing to wait in line for only 30 minutes. After that, he will leave the queue and exit the bank. The term reneging is used for this type of behavior.

In Simulation Studio, you can enable reneging in a Queue block by selecting the Reneging option in the Block Properties dialog box. When an entity enters the Queue block and the Reneging option is selected, the Queue block attempts to pull a numeric value from its InRenegeWait port. If the Queue block pulls a nonnegative number from the port, it will schedule a time for the entity to exit the block via the OutRenege port. When the renege time is reached, the Queue block sends the entity out the OutRenege port if the entity is still in the block and if the OutRenege port has a connection to it. If there is no connection to the OutRenege port, then no reneging occurs.