Implementation and Evaluation of Data Center Congestion Controller with Switch Assistance

In this work, we provide the design and implementation of a switch-assisted congestion control algorithm for data center networks (DCNs). In particular, we provide a prototype of the switch-driven congestion control algorithm and deploy it in a real data center. The prototype is based on few simple modifications to the switch software. The modifications imposed by the algorithm on the switch are to enable the switch to modify the TCP receive-window field in the packet headers. By doing so, the algorithm can enforce a pre-calculated (or target rate) to limit the sending rate at the sources. Therefore, the algorithm requires no modifications to the TCP source or receiver code which considered out of the DCN operators' control (e.g., in the public cloud where the VM is maintained by the tenant). This paper describes in detail two implementations, one as a Linux kernel module and the second as an added feature to the well-known software switch, Open vSwitch. Then we present evaluation results based on experiments of the deployment of both designs in a small testbed to demonstrate the effectiveness of the proposed technique in achieving high throughput, good fairness, and short flow completion times for delay-sensitive flows.Comment: arXiv admin note: text overlap with arXiv:2012.0033

Design and Implementation of Fair Congestion Control for Data Centers Networks

In data centers, the nature of the composite bursty traffic along with the small bandwidth-delay product and switch buffers lead to several congestion problems that are not handled well by traditional congestion control mechanisms such as TCP. Existing work try to address the problem by modifying TCP to suit the operational nature of data centers. This is practically feasible in private settings, however, in public environments, such modifications are prohibited. Therefore, in this work, we design simple switch-based queue management to deal with such congestion issues adequately. This approach entails no modification to the TCP sender and receiver algorithms which enables easy and seamless deployment in public data centers. We present a theoretical analysis to show the stability and effectiveness of the scheme. We also present, three different real implementations (as a Linux kernel module and as an added feature to OpenvSwitch) and give numerical results from both NS-2 simulation and experiments of real deployment in a small test-bed cluster to show its effectiveness in achieving high throughput overall, a good fairness and short flow completion times for delay-sensitive flows