In general there are 3 types of print queues. Queue with filtering, raw queue and CUPS class.
Queue with Filtering . has assigned a PPD file which defines which filter it uses and which options can be set.
Raw Queue . doesn't perform filtering at all.
CUPS Class . just forwards the job to one of the queues that are members of the class.
We can divide queues by connection. See Chapter 2, Printer Connection Types for connection reference. But from the viewpoint of printer configuration there are no internal differences between various types of queues.