The concept has been further developed into weighted fair queuing, and the more general concept of traffic shaping, where queuing priorities are dynamically controlled to achieve desired flow quality of service goals or accelerate some flows ( see net neutrality ).
12.
Weighted fair queuing ( WFQ ) is also known as Packet-by-Packet GPS ( PGPS or P-GPS ) since it approximates generalized processor sharing " to within one packet transmission time, regardless of the arrival patterns ."
13.
Therefore, GPS is mostly a theoretical idea, and several scheduling algorithms have been developed to approximate this GPS ideal : PGPS, aka Weighted fair queuing, is the most known implementation of GPS, but its has some drawbacks, and several other implementations have been proposed, as Deficit round robin or WF2Q.
14.
Packet mode communication may be implemented with or without intermediate forwarding nodes ( packet switches or first-in, first-out buffering, but may be forwarded according to some scheduling discipline for fair queuing, traffic shaping, or for differentiated or guaranteed quality of service, such as weighted fair queuing or leaky bucket.
