Multi-Resource Generalized Processor Sharing for Packet Processing

Middleboxes have found widespread adoption in today's networks. They perform a variety of network functions such as WAN optimization, intrusion detection, and network-level firewalls. Processing packets to serve these functions often require multiple middlebox resources, e. g., CPU and link bandwidth. Furthermore, different packet traffic flows may consume significantly different amounts of various resources, depending on the network functions that are applied. Multi-resource fair queueing is therefore needed to allow flows to share multiple middlebox resources in a fair manner. In this paper, we clarify the fairness requirements of a queueing scheme and present Dominant Resource Generalized Processor Sharing (DRGPS), a fluid flow-based fair queueing idealization that strictly realizes Dominant Resource Fairness (DRF) at all times. As a form of Generalized Processor Sharing (GPS) running on multiple resources, DRGPS serves as a benchmark that practical packet-by-packet fair queueing algorithm should follow. With DRGPS, techniques and insights that have been developed for traditional fair queueing can be leveraged to schedule multiple resources. As a case study, we extend Worst-case Fair Weighted Fair Queueing (WF(2)Q) to the multi-resource setting and analyze its performance.