In today's commercial data centers, the computation density grows continuously as the number of hardware components and workloads in units of virtual machines increase. The service availability guaranteed by data centers heavily depends on the reliability of the physical and virtual servers. In this study, we conduct an analysis on 10K virtual and physical machines hosted on five commercial data centers over an observation period of one year. Our objective is to establish a sound understanding of the differences and similarities between failures of physical and virtual machines. We first capture their failure patterns, i.e., the failure rates, the distributions of times between failures and of repair times, as well as, the time and space dependency of failures. Moreover, we correlate failures with the resource capacity and run-time usage to identify the characteristics of failing servers. Finally, we discuss how virtual machine management actions, i.e., consolidation and on/off frequency, impact virtual machine failures.

The Square Kilometre Array (SKA) is a future radio telescope, currently being designed by the worldwide radio-astronomy community. During the first of two construction phases, more than 250,000 antennas will be deployed, clustered in aperture-array stations. The antennas will generate 2.5 Pb/s of data, which needs to be processed in real time. For the processing stages from A/D conversion to central correlation, we propose an ASIC solution using only three chip architectures. The architecture is scalable - additional chips support additional antennas or beams - and versatile - it can relocate its receiver band within a range of a few MHz up to 4GHz. This flexibility makes it applicable to both SKA phases 1 and 2. The proposed chips implement an antenna and station processor for 289 antennas with a power consumption on the order of 600W and a correlator, including corner turn, for 911 stations on the order of 90 kW.

A couple of trends are going to be of significant importance in the next decennium. There will be a confluence of developments which are already visible today: ubiquitous, world wide deployment and access to data through a world wide infrastructure, using mobile devices as well as wired devices; the need for every enterprise in the world to look ahead, in order to stay competitive and even survive; a rapidly increasing availability of data, world wide, on customer preferences, behaviors and needs; a quickly increasing need to address a more efficient use of natural resources; and this all coupled with an increasing capability to join various types of data in a computing infrastructure to actually be able to look ahead. Let's address these one by one.

Emerging Internet applications create the need for advanced packet classifiers. We propose a novel multifield classification scheme, called P2C, which exploits the strengths of state-of-the-art memory technologies to provide wire-speed classification performance for OC-192 and beyond, in combination with very high storage efficiency and the support of fast incremental updates. Key features of the new scheme are its ability to adapt to the complexity of a classification rule set, whereas the storage requirements and update dynamics can be tuned at the granularity of individual rules. This makes P2C suitable for a broad spectrum of applications.

Emerging Internet applications create the need for advanced packet classifiers. This paper investigates the mechanisms that determine the performance of state-of-the-art multi-field classification methods, and proposes a novel scheme called P/sup 2/C for packet classification at OC-192 and OC-768 speeds. P/sup 2/C combines the strengths of embedded memory and ternary CAM technologies to achieve very high storage efficiency while maintaining fast incremental updates. Key feature of the new scheme Is Its ability to adapt to the complexity of a classification rule set, while providing effective control over the update dynamics and storage requirements at the granularity of individual rules. This makes P/sup 2/C suitable for a broad range of applications.

A hierarchical decomposition of network nodes which permits the networkwide topology database and algorithms to be independent of node internals, yet allows (implicit) access to special intranodal features when required is described. A complementary procedure for the establishment of bandwidth-reserved connections is outlined that makes efficient use of this node structure to support network-level optimization through use of node-level features. Based on a significantly increased concurrency of path computation and bandwidth reservation, the execution time of the setup procedure is independent of the network's complexity (such as number of nodes and links) and is essentially bounded from above by the round-trip delay only.>