NUFTCP: Towards Smooth Network Updates in Software-Defined Datacenter Networks

Since the widespread deployment of the Software Defined Network in the datacenter, network updates become more and more common. However, modern TCP designs are not resilient to network updates, which introduce flow reroutes. Frequent and inconsistent network updates lead to severe performance degradation such as packet drop (caused by transient congestion) and out-of-order packets problems. In this paper, we verify and show the poor performance of common TCP implementations when there are frequent network updates. We analyze the reasons and propose a simple variant of DCTCP as a countermeasure, named NUFTCP (Network Update Friendly TCP). We evaluate NUFTCP with simulations. The results demonstrate that NUFTCP can more efficiently handle the problems of packet drop and out-of-order packets caused by network updates.