  The peculiar congestion patterns in data centers are caused by the bursty and
composite nature of traffic, the small bandwidth-delay product, and the tiny
switch buffers. It is not practical to modify TCP to adapt to data centers,
especially in public clouds where multiple congestion control protocols
coexist. In this work, we design a switch-based method to address such
congestion issues; our approach does not require any modification to TCP, which
enables easy and seamless deployment in public data centers via switch software
update. We first present a simple analysis to demonstrate the stability and
effectiveness of the scheme, and then we discuss a hardware NetFPGA
switch-based prototype. The experimental results from real deployments in a
small testbed cluster show the effectiveness of our approach.
