[FYI] Are there other types of blocking in queueing networks beyond Type I? about ciw HOT 1 CLOSED

Yes, my go-to reference is: https://www.sciencedirect.com/science/article/abs/pii/0167637786900672

Type 1: customers are blocked after finishing service.
Type 2: customers are blocked before starting service (that is, service only starts once we know they can move on). I think this is difficult to generalise in networks, where the way ahead might get filled up during the service time.
Type 3: customers repeat their service until the path ahead is clear.

Type 3 blocking might be possible in Ciw. I have never seen a need for it though, but could be explored.

from ciw.