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In multi-tenant datacenters, jobs of different tenants compete for the shared datacenter network and can suffer poor performance and high cost from varying, unpredictable network performance. Recently, several virtual network abstractions have been proposed to provide explicit APIs for tenant jobs to specify and reserve virtual clusters (VC) with both(More)
Critical network management applications increasingly demand fine-grained flow level measurements. However , current flow monitoring solutions are inadequate for many of these applications. In this paper, we present the design, implementation, and evaluation of CSAMP, a system-wide approach for flow monitoring. The design of CSAMP derives from three key(More)
—Modern data center networks are commonly organized in multi-rooted tree topologies. They typically rely on equal-cost multipath to split flows across multiple paths, which can lead to significant load imbalance. Splitting individual flows can provide better load balance, but is not preferred because of potential packet reordering that conventional wisdom(More)
Automated, rapid, and effective fault management is a central goal of large operational IP networks. Today's networks suffer from a wide and volatile set of failure modes, where the underlying fault proves difficult to detect and localize, thereby delaying repair. One of the main challenges stems from operational reality: IP routing and the underlying(More)
— Internet backbone networks are under constant flux, so as to keep up with demand and to offer new features. The pace of change in features and technology often outstrips the pace of introduction of the associated fault monitoring capabilities that are built into today's IP protocols and routers. Moreover, some of these new technologies cross networking(More)
In this paper, we observe that bandwidth sharing via TCP in commodity data center networks organized in multi-rooted tree topologies can lead to severe unfair-ness, which we term as the TCP Outcast problem, under many common traffic patterns. When many flows and a few flows arrive at two ports of a switch destined to one common output port, the small set of(More)
Distributed controllers have been proposed for Software Defined Networking to address the issues of scalability and reliability that a centralized controller suffers from. One key limitation of the distributed controllers is that the mapping between a switch and a controller is <i>statically configured</i>, which may result in uneven load distribution among(More)
Network sampling is integral to the analysis of social, information, and biological networks. Since many real-world networks are massive in size, continuously evolving, and/or distributed in nature, the network structure is often sampled in order to facilitate study. For these reasons, a more thorough and complete understanding of network sampling is(More)
Many network applications have stringent end-to-end latency requirements, including VoIP and interactive video conferencing, automated trading, and high-performance computing---where even microsecond variations may be intolerable. The resulting fine-grain measurement demands cannot be met effectively by existing technologies, such as SNMP, NetFlow, or(More)
Recent advances in virtualization technologies have made it feasible to host multiple virtual machines (VMs) in the same physical host and even the same CPU core, with fair share of the physical resources among the VMs. However, as more VMs share the same core/CPU, the CPU access latency experienced by each VM increases substantially, which translates into(More)