- Romania
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Analysis and Modeling.- Network Characteristics: Modelling, Measurements, and Admission Control.- Statistical Characterization for Per-hop QoS.- Performance Analysis of Server Sharing Collectives for Content Distribution.- An... more
Analysis and Modeling.- Network Characteristics: Modelling, Measurements, and Admission Control.- Statistical Characterization for Per-hop QoS.- Performance Analysis of Server Sharing Collectives for Content Distribution.- An Approximation of the End-to-End Delay Distribution.- Resource Allocation and Admission Control.- Price-Based Resource Allocation in Wireless Ad Hoc Networks.- On Achieving Fairness in the Joint Allocation of Processing and Bandwidth Resources.- Distributed Admission Control for Heterogeneous Multicast with Bandwidth Guarantees.- Multimedia & Incentives.- Subjective Impression of Variations in Layer Encoded Videos.- A Moving Average Predictor for Playout Delay Control in VoIP.- To Play or to Control: A Game-Based Control-Theoretic Approach to Peer-to-Peer Incentive Engineering.- Dependability and Fault Tolerance.- Improving Dependability of Real-Time Communication with Preplanned Backup Routes and Spare Resource Pool.- Fault Tolerance in Networks with an Advance Reservation Service.- Routing.- Routing and Grooming in Two-Tier Survivable Optical Mesh Networks.- Fast Network Re-optimization Schemes for MPLS and Optical Networks.- HMP: Hotspot Mitigation Protocol for Mobile Ad hoc Networks.- Availability and Dependability.- Failure Insensitive Routing for Ensuring Service Availability.- Network Availability Based Service Differentiation.- Quality of Availability: Replica Placement for Widely Distributed Systems.- Web Services.- Using Latency Quantiles to Engineer QoS Guarantees for Web Services.- DotQoS - A QoS Extension for .NET Remoting.- Dynamic Resource Allocation for Shared Data Centers Using Online Measurements.- Rate-Based QoS.- Providing Deterministic End-to-End Fairness Guarantees in Core-Stateless Networks.- Per-domain Packet Scale Rate Guarantee for Expedited Forwarding.- On Achieving Weighted Service Differentiation: An End-to-End Perspective.- Storage.- Online Response Time Optimization of Apache Web Server.- A Practical Learning-Based Approach for Dynamic Storage Bandwidth Allocation.- CacheCOW: QoS for Storage System Caches.
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AbstractThe rapid growth of the Internet has made IPv4 addresses a scarce resource. Today we witness two major trends to get around this problem. The first is to upgrade and deploy networks using IPv6; the second is to deploy net-works... more
AbstractThe rapid growth of the Internet has made IPv4 addresses a scarce resource. Today we witness two major trends to get around this problem. The first is to upgrade and deploy networks using IPv6; the second is to deploy net-works using reusable-IPv4 addresses. As a result, ...
We describe a new approach to implement proportional share resource allocation and to provide di erent levels of service quality. We consider multiple clients that compete for a time-shared resource, and we associate to each client a... more
We describe a new approach to implement proportional share resource allocation and to provide di erent levels of service quality. We consider multiple clients that compete for a time-shared resource, and we associate to each client a certain amount of funds. At the ...
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... successful kidney transplantation. Auteur(s) / Author(s). JOSEPH LJ (1) ; DESAI KB (1) ; MEHTA HJ (1) ; MEHTA MN (1 2) ; ALMEIDA AF (2) ; ACHARYA VN (2) ; SAMUEL AM (1) ; Affiliation(s) du ou des auteurs / Author(s) Affiliation(s). ...
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To provide routing flexibility, that is, to accommodate vari- ous performance and policy goals, routing protocols (such as OSPF and EIGRP) include many complex knobs. Owing to this complexity, protocols today do not adequately satisfy... more
To provide routing flexibility, that is, to accommodate vari- ous performance and policy goals, routing protocols (such as OSPF and EIGRP) include many complex knobs. Owing to this complexity, protocols today do not adequately satisfy their main goal—to provide connectivity between nodes in the face of failures and misconfigured nodes. In this paper, we ask the question of how one can design routing proto- cols that are flexible, yet provide connectivity in the face of failures and misconfigurations. To this end, we propose a dif- ferent routing paradigm that decouples the task of providing basic connectivity from sophisticated routing operations. We propose an underlying Basic Connectivity Routing Protocol (BCRP) that is robust to link failures and prevents miscon- figured nodes from arbitrarily subverting traffic. Routing can then be made flexible by layering sophisticated route selec- tion on top of BCRP; these protocols fall back to BCRP when failures are encountered.
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Matei Zaharia is a fifth year PhD student at UC Berkeley, working with Scott Shenker and Ion Stoica on topics in computer systems, networks, cloud computing, and big data. He is also a committer on Apache Hadoop and Apache
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Neural programs are highly accurate and structured policies that perform algorithmic tasks by controlling the behavior of a computation mechanism. Despite the potential to increase the interpretability and the compositionality of the... more
Neural programs are highly accurate and structured policies that perform algorithmic tasks by controlling the behavior of a computation mechanism. Despite the potential to increase the interpretability and the compositionality of the behavior of artificial agents, it remains difficult to learn from demonstrations neural networks that represent computer programs. The main challenges that set algorithmic domains apart from other imitation learning domains are the need for high accuracy, the involvement of specific structures of data, and the extremely limited observability. To address these challenges, we propose to model programs as Parametrized Hierarchical Procedures (PHPs). A PHP is a sequence of conditional operations, using a program counter along with the observation to select between taking an elementary action, invoking another PHP as a sub-procedure, and returning to the caller. We develop an algorithm for training PHPs from a set of supervisor demonstrations, only some of w...
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Distributed storage employs replication to mask failures and improve availability. However, these systems typically exhibit a hard tradeoff between consistency and performance. Ensuring consistency introduces coordination overhead, and as... more
Distributed storage employs replication to mask failures and improve availability. However, these systems typically exhibit a hard tradeoff between consistency and performance. Ensuring consistency introduces coordination overhead, and as a result the system throughput does not scale with the number of replicas. We present Harmonia, a replicated storage architecture that exploits the capability of new-generation programmable switches to obviate this tradeoff by providing near-linear scalability without sacrificing consistency. To achieve this goal, Harmonia detects read-write conflicts in the network, which enables any replica to serve reads for objects with no pending writes. Harmonia implements this functionality at line rate, thus imposing no performance overhead. We have implemented a prototype of Harmonia on a cluster of commodity servers connected by a Barefoot Tofino switch, and have integrated it with Redis. We demonstrate the generality of our approach by supporting a varie...
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Almost six years ago we started the Spark project at UC Berkeley. Spark is a cluster computing engine that is optimized for in-memory processing, and unifies support for a variety of workloads, including batch, interactive querying,... more
Almost six years ago we started the Spark project at UC Berkeley. Spark is a cluster computing engine that is optimized for in-memory processing, and unifies support for a variety of workloads, including batch, interactive querying, streaming, and iterative computations. Spark is now the most active big data project in the open source community, and is already being used by over one thousand organizations. One of the reasons behind Spark's success has been our early bet on the continuous increase in the memory capacity and the feasibility to fit many realistic workloads in the aggregate memory of typical production clusters. Today, we are witnessing new trends, such as Moore's law slowing down, and the emergence of a variety of computation and storage technologies, such as GPUs, FPGAs, and 3D Xpoint. In this talk, I'll discuss some of the lessons we learned in developing Spark as a unified computation platform, and the implications of today's hardware and software tr...
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While SCORE/DPS based solutions are much more scalable and, in the case of fail-stop failures, more robust than their stateful counterparts, they are less scalable and robust than the stateless solutions. The scalability of the SCORE... more
While SCORE/DPS based solutions are much more scalable and, in the case of fail-stop failures, more robust than their stateful counterparts, they are less scalable and robust than the stateless solutions. The scalability of the SCORE architecture suffers from the fact that the network core cannot transcend trust boundaries, such as the boundary between two competing Internet Service Providers (ISPs).
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Today, big and small organizations alike collect huge amounts of data, and they do so with one goal in mind: extract "value" through sophisticated exploratory analysis, and use it as the basis to make decisions as varied as... more
Today, big and small organizations alike collect huge amounts of data, and they do so with one goal in mind: extract "value" through sophisticated exploratory analysis, and use it as the basis to make decisions as varied as personalized treatment and ad targeting. Unfortunately, existing data analytics tools are slow in answering queries, as they typically require to sift through huge amounts of data stored on disk, and are even less suitable for complex computations, such as machine learning algorithms. These limitations leave the potential of extracting value of big data unfulfilled. To address this challenge, we are developing Berkeley Data Analytics Stack (BDAS), an open source data analytics stack that provides interactive response times for complex computations on massive data. To achieve this goal, BDAS supports efficient, large-scale in-memory data processing, and allows users and applications to trade between query accuracy, time, and cost. In this talk, I'll ...
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Recent research indicates that multi-hop wireless net-works can suffer from extreme imbalances in the throughput achieved by simultaneous competing flows. We address this problem by designing a practical distributed algorithm to compute a... more
Recent research indicates that multi-hop wireless net-works can suffer from extreme imbalances in the throughput achieved by simultaneous competing flows. We address this problem by designing a practical distributed algorithm to compute a time-slot based schedule that provides ...
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Research Interests: Computer Science, Algorithms, Computer Architecture, Software Engineering, Computer Networks, and 10 moreConcurrent Engineering, Data Management, Systems Analysis, Packet Switching, Parallel Processing, Mathematical Models, Message Passing, Parameters, Experimental Measurement, and Communication Cost
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Existing approaches for providing guaranteed services require routers to manage per flow states and perform per flow operations [9, 21]. Such a stateful network architecture is less scalable and robust than stateless network architectures... more
Existing approaches for providing guaranteed services require routers to manage per flow states and perform per flow operations [9, 21]. Such a stateful network architecture is less scalable and robust than stateless network architectures like the original IP and the recently proposed Diffserv [3]. However, services provided with current stateless solutions, Diffserv included, have lower flexibility, utilization, and/or assurance level as compared to the services that can be provided with per flow mechanisms.In this paper, we propose techniques that do not require per flow management (either control or data planes) at core routers, but can implement guaranteed services with levels of flexibility, utilization, and assurance similar to those that can be provided with per flow mechanisms. In this way we can simultaneously achieve high quality of service, high scalability and robustness. The key technique we use is called Dynamic Packet State (DPS), which provides a lightweight and robu...
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Data centers deploy a variety of middleboxes (e.g., firewalls, load balancers and SSL offloaders) to protect, manage and improve the performance of applications and services they run. Since existing networks provide limited support for... more
Data centers deploy a variety of middleboxes (e.g., firewalls, load balancers and SSL offloaders) to protect, manage and improve the performance of applications and services they run. Since existing networks provide limited support for middleboxes, administrators typically overload path selection mechanisms to coerce traffic through the desired sequences of middleboxes placed on the network path. These ad-hoc practices result in a data center network that is hard to configure and maintain, wastes middlebox resources, and cannot guarantee middlebox traversal under network churn. To address these issues, we propose the policy-aware switching layer or PLayer, a new layer-2 for data centers consisting of inter-connected policy-aware switches or pswitches. Unmodified middleboxes are placed off the network path by plugging them into pswitches. Based on policies specified by administrators, pswitches explicitly forward different types of traffic through different sequences of middleboxes. ...
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It is well-known that BGP, the current inter-domain routing protocol, has many deficiencies. This paper describes a hybrid link-state and path-vector protocol called HLP as an alternative to BGP that has vastly better scalability,... more
It is well-known that BGP, the current inter-domain routing protocol, has many deficiencies. This paper describes a hybrid link-state and path-vector protocol called HLP as an alternative to BGP that has vastly better scalability, isolation and convergence properties. Using current BGP routing information, we show that HLP, in comparison to BGP, can reduce the churn-rate of route updates by a