• Suresh Singh (PI) Professor of Computer Sciense, Portland State University

NSF Grant Number: 1217996

Duration: 9/2012 - 9/2015


Energy consumed by computing and communication devices has become a significant cost of conducting business today. Indeed, as we move to higher speed networks and increase the deployment of the Internet to all corners of the world, this cost is expected to grow dramatically. Major contributors to the size and energy cost of the deployed infrastructure include enterprise networks and data center networks. Enterprise networks are deployed in the workplace and have been shown to be heavily under-utilized with peak utilizations typically a fraction of capacity. Similarly, data center networks have also been shown to be very lightly loaded for significant lengths of time. In both these cases, the energy consumed by the networking infrastructure is very high, in relation to the actual data transmitted. The reasons for this are twofold. First, network switches are designed to always run at peak rates even in the absence of traffic and second, switch ports map one-to-one to end systems even though these systems load the ports at a tiny fraction of available capacity. The outcome of this research project is a fundamental re-design of the network switch in a way that preserves user experience but results in dramatic energy savings. The key idea in this work is the development of a hardware device called a merge network, which sits between the switch and connected systems. Traffic coming into the switch is merged together and fed to a smaller number of ports allowing either the replacement of large port-density switches with smaller switches or the powering off of large portions of the switch such as line cards and memory banks. While the benefit of this idea is evident, the challenges in realizing it are many. At the hardware level, the challenge is in merging traffic with minimal energy cost and data loss. The approach adopted in this project is to build the merge network using analog components with a digital control for managing Layer 2 protocol issues. Modern switches implement a suite of Layer 2 protocols that expect a 1-1 mapping of switch ports to end-systems. By breaking this mapping using a merge network, one effectively causes incorrect protocol behavior. This issue is addressed by utilizing port virtualization within each switch. Thus, the Layer 2 protocols remain unaffected while the network sees tremendous reduction in energy usage. The project uses prototyping, experimentation and simulation to fully characterize this new switch architecture in enterprise and data center networks. Experimental systems based on Click Modular Router will be inserted into the College network to measure the energy savings in real application as well as to understand side effects of such a redesign on overall network behavior. Traffic statistics collected at a data center network and the University-level enterprise network will be utilized in a simulator to analyze protocol behavior at a larger scale. This project is transformative in that it redesigns the basic building block of the Internet resulting in dramatic energy savings. The broader impact of this work ranges from fundamentally redesigning the key component of the Internet (the switch) to directly influencing the energy usage in the communications infrastructure. The impact on industry is significant in that the work here will influence the design of future high-speed switches where the merge network is incorporated into the architecture rather than as an external add on. Traffic statistics collected during this project will be made available to the research community and will thus provide a much-needed source of enterprise-level traces. The research community will also benefit by the implementation of IEEE 802.1 protocols into the Click software base. The project will enhance the training of the future workforce via the development of a new class and including students in hands on measurement and development of the experimental platform.