Using CPU as a Traffic Co-processing Unit in Commodity Switches

Commodity switches are becoming increasingly important as they are the basic building blocks for the enterprise and data center networks. With the availability of all-in-one
switching ASICs, these switches almost universally adopt single switching ASIC design. However, such design also brings two major limitations,i.e, limited forwarding table for flow-based forwarding scheme such as Openflow and shal-low buffer for bursty traffic pattern. In this paper, we pro-pose to use CPU in the switches to handle not only control plane but also data plane traffic. We show that this design can provide large forwarding table for flow-based forwarding scheme and deep packet buffer for bursty traffic. We build such a prototype switch on ServerSwitch platform. In our evaluation, we show that our prototype can achieve over 90% traffic offloading ratio, absorb large traffic bursts without a
single packet drop, and can be easily programmed to detect and defend low-rate burst attacks.