New technology i just learned about! Its called PIPQ, and stands for PVC Interface Priority Queueing.
As the name implies, its a Queueing method, and its only for frame-relay.
It basically functions in the same way as a PQ scheme, in that it has 4 queues, high, medium, normal and low.
Where it differs is that instead of putting packets into each queue, you “put PVC’s” into each queue, or rather, you designate into which queue this specific PVC should belong to.