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GUEST EDITORIAL
Cloud and Data Center Performance
Bo Li
M
Baochun Li
odern data centers, consisting of massive farms of servers and abundant bandwidth availability, are becoming the next computing platform for the Internet. Cloud computing, as an efficient means of providing computing resources in the form of utility, uses data centers to play its pivotal role of leasing computing and storage resources to users. Cloud computing has already become prevalent with the burgeoning of cloud service providers, such as Amazon EC2 and Google App Engine. The paradigm shift to cloud computing is driven by a strong demand, especially from enterprises, to improve the overall efficiency of using and managing computing resources. With the rapid growth of cloud users and an increasing number of resource-demanding applications deployed, it is critically important to understand and improve the performance of cloud computing platforms so that performance needs from hosted applications can be satisfied. In particular, the geographically distributed nature of data centers in the cloud and the architectural shift to container-based data centers have posed new challenges in the design, deployment, and management of cloud computing platforms. These challenges, across different layers of data center networks (DCNs), mainly include: • Rising challenges and solutions of future DCNs and cloud computing infrastructures • Competing DCN architectures and communication technologies, such as data center bridging (DCB) in IEEE 802.1 and Fibre Channel over Ethernet (FCoE) • DCN traffic characteristics, and innovative traffic engineering and protocol design • Instrumentation, measurement, and evaluation of cloud and data center performance • The migration of emerging Internet-scale applications to cloud platforms This Feature Topic consists of five articles addressing the various aspects of cloud and data center performance, such as future development of DCN architectures, unique
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Fangming Liu
DCN traffic characteristics and protocol design, as well as performance measurement and analysis of emerging cloud applications such as cloud gaming. The Feature Topic opens with a comprehensive survey on enabling DCN technologies for future cloud infrastructures, through which the huge amount of resources in data centers can be efficiently managed. Specifically, in “Enabling Technologies for Future Data Center Networking: A Primer,” Chen et al. provide a detailed investigation of the architecture, technologies, and design principles for future data center networking, with the presence of diverse types of data traffic from cloud computing services, social media, and mobile communications. The article also highlights some of the design challenges to improve the energy efficiency in future DCNs, while increasing throughput at low cost. Computer gaming represents one of the major markets of the overall IT industry. However, today’s high-quality games often demand powerful hardware/software configurations that are not readily available on thin clients such as handheld devices. Current advances in cloud technologies have turned the idea of cloud gaming into a reality, which, in its simplest form, renders an interactive gaming application remotely in the cloud and streams the scenes as a video sequence back to the player over the Internet. In the second article, “Cloud Gaming: Architecture and Performance,” Shea et al. conduct a systematic analysis of stateof-the-art cloud gaming platforms, and highlight the uniqueness of their framework design. They also measure the real-world performance with different types of games, for both interaction latency and streaming quality, revealing critical challenges toward the widespread deployment of cloud-based gaming platforms. Special features and traffic characteristics in DCNs, such as low round-trip times, many-to-one traffic patterns, virtualization, and multiple topology paths, have posed substantial challenges to traditional TCP transport protocols used by current Internet infrastructure. How the new generation
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GUEST EDITORIAL of transport protocols are to be designed for DCNs has attracted a substantial amount of research attention. In the third article, “Survey on Transport Protocol in Data Center Networks,” J. Zhang et al. has summarized the research issues related to the transport layer in DCNs, such as TCP incast, long latencies of short flows, unstable throughput in virtualized environments, and bandwidth sharing in multitenant data centers. The authors start with the unique features of DCNs, and the causes, current research progress, and possible research directions with respect to each of the problems are described in later sections of the article. Traditional DCNs have employed multiple networks such as Ethernet and Fibre Channel (FC) to meet heterogeneous traffic demands, and are therefore presented with unique challenges due to the high cost and complexity of managing multiple networks. Converged data center networks will likely solve this problem by using only one core network fabric to support all types of traffic. In the fourth article, “Survey on Converged Data Center Networks with DCB and FCoE: Standards and Protocols,” Cai et al. present a survey on the emerging standards and protocols that will enable the enhanced Ethernet to meet the demands for converged data center networks. The authors first discuss standards that will enable Ethernet to better support traffic with various requirements, and then describe protocols that will allow the FC traffic to be encapsulated in Ethernet frames. Standards designed for better network efficiency and virtualization are also discussed. Last but not least, in the article titled “Sketching the Data Center Network Traffic,” Liu et al. attempt to solve the challenge of identifying the cause of congestion in real time in DCNs with high accuracy, low computational complexity, and good scalability with the exploding data. Specifically, the authors propose two sketch-based algorithms, called a-CU and P(d)-CU, based on the existing conservative update (CU) approach. a-CU adds no extra implementation cost to the traditional CU, but successfully trades off the achieved error with time complexity. P(d)CU fully considers the amount of skew for different network services to aggregate traffic statistics of each service type at individual horizontally partitioned sketch. The authors also introduce a way to produce the real-time moving average of the reported results. Then the effectiveness of the proposed algorithms has been verified using experiments with realistic DCN traces. In closing, we would like to thank all the authors who submitted their research work to this Feature Topic. We would also like to acknowledge the contribution of many
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experts in the field who have participated in the review process, and provided helpful suggestions to the authors for improving the content and presentation of the articles. In particular, we would like to thank Professor Sherman Shen, the Editor-in-Chief, for his support and very constructive suggestions and comments during the critical stages of concluding the Feature Topic.
Biographies B O L I [F] (
[email protected]) is a professor in the Department of Computer Science and Engineering, Hong Kong University of Science and Technology. His current research interests include large-scale content distribution in the Internet, data center networking, cloud computing, and mobile sensor networks. He made pioneering contributions in the Internet video broadcast with a system called Coolstreaming (the keyword had over 2,000,000 entries on Google), which was credited as the world first large-scale peer-to-peer live video streaming system, which spearheaded a movement in the video broadcast industry, with no fewer than a dozen successful companies adopting the same mesh-based pull streaming technique to deliver live media content to hundreds of millions of users in the world. He has been an Editor or a Guest Editor for a dozen IEEE journals and magazines. He was Co-TPC Chair for IEEE INFOCOM 2004. He received his B.Eng. degree in computer science from Tsinghua University, Beijing, China, and his Ph.D. degree in electrical and computer engineering from the University of Massachusetts at Amherst. BAOCHUN LI [SM] (
[email protected]) is a professor with the Department of Electrical and Computer Engineering at the University of Toronto, Canada. He received his B.Eng. degree from the Department of Computer Science and Technology, Tsinghua University, in 1995, and his M.S. and Ph.D. degrees from the Department of Computer Science, University of Illinois at UrbanaChampaign, in 1997 and 2000. He held the Nortel Networks Junior Chair in Network Architecture and Services from October 2003 to June 2005, and has held the Bell Canada Endowed Chair in Computer Engineering since August 2005. His research interests include large-scale distributed systems, cloud computing, peer-to-peer networks, applications of network coding, and wireless networks. He was the recipient of the IEEE Communications Society Leonard G. Abraham Award in the Field of Communications Systems in 2000. In 2009, he was a recipient of the Multimedia Communications Best Paper Award from the IEEE Communications Society and the University of Toronto McLean Award. He is a member of ACM. FANGMING LIU [M] (
[email protected]) is an associate professor in the School of Computer Science and Technology, Huazhong University of Science and Technology, Wuhan, China, and he is the CHUTIAN Scholar of Hubei Province, China. He is the Youth Scientist of the National 973 Basic Research Program Project “Software-Defined Networking (SDN)-Based Cloud Datacenter Networks: Fundamental Theories and Key Technologies,” which is one of the largest SDN projects in China. Since 2012, he has also been invited as a StarTrack Visiting Young Faculty in Microsoft Research Asia (MSRA), Beijing. He received his B.Eng. degree in 2005 from the Department of Computer Science and Technology, Tsinghua University, and his Ph.D. degree in computer science and engineering from the Hong Kong University of Science and Technology in 2011. From 2009 to 2010, he was a visiting scholar at the Department of Electrical and Computer Engineering, University of Toronto. He was the recipient of two Best Paper Awards from IEEE GLOBECOM ’11 and IEEE CloudCom ’12, respectively. His research interests include cloud computing and data center networking, mobile cloud, green computing and communications, software-defined networking and virtualization technology, large-scale Internet content distribution, and video streaming systems. He is a member of ACM, as well as a member of the China Computer Federation (CCF) Internet Technical Committee. He has been a Guest Editor for IEEE Network, an Associate Editor of Frontiers of Computer Science , and a TPC member of IEEE INFOCOM ’13–’14 and GLOBECOM ’12–’13.
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