Andrei Voinescu

Bio: Andrei Voinescu is an academic researcher from Politehnica University of Bucharest. The author has contributed to research in topics: Wireless sensor network & Key distribution in wireless sensor networks. The author has an hindex of 9, co-authored 14 publications receiving 844 citations. Previous affiliations of Andrei Voinescu include University of Bucharest.

Re-architecting datacenter networks and stacks for low latency and high performance

Abstract: Modern datacenter networks provide very high capacity via redundant Clos topologies and low switch latency, but transport protocols rarely deliver matching performance. We present NDP, a novel data-center transport architecture that achieves near-optimal completion times for short transfers and high flow throughput in a wide range of scenarios, including incast. NDP switch buffers are very shallow and when they fill the switches trim packets to headers and priority forward the headers. This gives receivers a full view of instantaneous demand from all senders, and is the basis for our novel, high-performance, multipath-aware transport protocol that can deal gracefully with massive incast events and prioritize traffic from different senders on RTT timescales. We implemented NDP in Linux hosts with DPDK, in a software switch, in a NetFPGA-based hardware switch, and in P4. We evaluate NDP's performance in our implementations and in large-scale simulations, simultaneously demonstrating support for very low-latency and high throughput.

Stateless Datacenter Load-balancing with Beamer

Abstract: Datacenter load balancers (or muxes) steer traffic destined to a given service across a dynamic set of backend machines. To ensure consistent load balancing decisions when backends come or leave, existing solutions make a load balancing decision per connection and then store it as per-connection state to be used for future packets. While simple to implement, per-connection state is brittle: SYNflood attacks easily fill state memory, preventing muxes from keeping state for good connections. We present Beamer, a datacenter load-balancer that is designed to ensure stateless mux operation. The key idea is to leverage the connection state already stored in backend servers to ensure that connections are never dropped under churn: when a server receives a mid-connection packet for which it doesn’t have state, it forwards it to another server that should have state for the packet. Stateless load balancing brings many benefits: our software implementation of Beamer is twice faster than Google’s Maglev, the state of the art software load balancer, and can process 40Gbps of HTTP uplink traffic on 7 cores. Beamer is simple to deploy both in software and in hardware as our P4 implementation shows. Finally, Beamer allows arbitrary scale-out and scale-in events without dropping any connections.

Home automation design using 6LoWPAN wireless sensor networks

Abstract: Wireless sensor and actuator networks (WS&ANs) are a new technology based on networks of small radio-enabled embedded devices that are being deployed in areas such as environmental monitoring, vehicle tracking, building management, body monitoring and other applications. Power sources for network nodes are often limited, which imposes restrictions on hardware resources and their use by the underlying embedded software. We propose a new wireless sensor network architecture that is especially designed for the task of home automation. Our system relies on a low power WS&AN that employs energy harvesting techniques to maximize node lifetime and an embedded residential gateway that offers user interaction and secure connectivity to the outside world. The advantages of our system are its scalability, low power, self sufficiency and versatility.

Mobile sensors in air pollution measurement

Abstract: In this paper we present a mobile system for air quality and pollution measurement suited for the urban environment. We designed, tested and built a reliable measurement device that can acquire information about the air quality of its surroundings, store it in a temporary memory buffer and periodically relay it to a central on-line repository. Real-time gathered data can be freely accessed by the public through an on-line web interface. Users can select and view different gases and concentrations overlapped on a map of the city.

HPCC: high precision congestion control

Abstract: Congestion control (CC) is the key to achieving ultra-low latency, high bandwidth and network stability in high-speed networks. From years of experience operating large-scale and high-speed RDMA networks, we find the existing high-speed CC schemes have inherent limitations for reaching these goals. In this paper, we present HPCC (High Precision Congestion Control), a new high-speed CC mechanism which achieves the three goals simultaneously. HPCC leverages in-network telemetry (INT) to obtain precise link load information and controls traffic precisely. By addressing challenges such as delayed INT information during congestion and overreac-tion to INT information, HPCC can quickly converge to utilize free bandwidth while avoiding congestion, and can maintain near-zero in-network queues for ultra-low latency. HPCC is also fair and easy to deploy in hardware. We implement HPCC with commodity programmable NICs and switches. In our evaluation, compared to DCQCN and TIMELY, HPCC shortens flow completion times by up to 95%, causing little congestion even under large-scale incasts.

Survey on the Characterization and Classification of Wireless Sensor Network Applications

Abstract: Nowadays, wireless sensor network (WSN) users are demanding more and more in terms of choice and diversity of applications. Hence, as the diversity of applications is increasing, it is worthwhile to propose a structure for the set of characterization parameters that allows sketching a taxonomy for WSN applications. This taxonomy is established via an application-oriented approach, identifying the specific services offered by each application. In this survey, we fill this gap in the WSN literature by describing the characterization parameters, organized into six different categories. Our taxonomy for application classification is centered on the different sets of parameters that have high impact on a given future WSN application. Typical attributes and values from related research works are considered as a reference, but in this survey, we propose inter- and intra-connections among the considered application groups. Based on these connections, new application groups have been proposed for applications that share common characterization parameters, along with a holistic overview of WSN application taxonomy and the discussion of the three generations of WSNs toward communication between things and the Internet of Things , as well as future trends for the development of WSN applications. Moreover, detailed parameters from different projects and authors in the field of WSNs are joined together for comparison purposes.