Data Center Transport Mechanisms: Congestion Control Theory and IEEE Standardization

Balaji Prabhakar – Researcher, Stanford University


Balaji Prabhakar

Data Center Networks present a novel, unique and rich environment for algorithm and protocol development. Projects are underway at the IEEE 802.1 standards body, especially in the Data Center Bridging Task Group, to define new Ethernet functions for data center use. We describe one such project, IEEE 802.1Qau, which aims to develop an Ethernet congestion control algorithm. An analysis of the algorithm (called QCN) developed for the standard led to the discovery of a simple method for making congestion control loops stable in the face of increasing lags. This method, called the Averaging Principle, is applicable for stabilizing general control loops, not just congestion control loops. We shall describe our development of the QCN algorithm and the Averaging Principle.


Balaji Prabhakar is an Associate Professor of Electrical Engineering and Computer Science at Stanford University. Balaji is interested in network algorithms, in scaleable methods for network performance monitoring and simulation, in wireless (imaging) sensor networks, stochastic network theory and information theory. He has designed algorithms for switching, routing, bandwidth partitioning, load balancing, and web caching. Balaji has been a Terman Fellow at Stanford University and a Fellow of the Alfred P. Sloan Foundation. He has received the CAREER award from the National Science Foundation, the Erlang Prize from the INFORMS Applied Probability Society, and the Rollo Davidson Prize awarded to young scientists for their contributions to probability and its applications.