Off-the-path flow handling mechanism forhigh-speed and programmable traffic management

In this paper, we propose a high-speed and programmable traffic management mechanism to enable easy and timely innovations. A control framework introduced by 4D, Tesseract, or OpenFlow, separates control functions from the switch nodes to a control server so that a variety of network control policies can be implemented outside of the switches. Within this framework, we propose a mechanism to enable flexible flow-based traffic management so that a variety of innovative traffic management schemes can be realized. Per-flow traffic management, however, requires packet-by-packet state updates, which can spoil this control framework. The proposed mechanism consists of a control server that monitors traffic conditions using sampled packets sent from the switches and calculates per-flow packet discarding rate, and switches that discard incoming packets according to the discarding rate. Packet sampling and discarding do not require packet-by-packet state handling at the switches and thus allows controls from a control server. We also propose a mechanism to compress the discarding information using a time series of bloom filters, so that frequent control updates are allowed. We tested the mechanism with per-flow WFQ emulation and the simulation results showed very good per-flow fairness. Furthermore, we found that the flow table is compressed 600 times smaller and that the processing cost at the server and the switches is small enough for use with 10 Gbps links.