Sándor Laki

Dr. Sándor Laki

ELTE, Eötvös Loránd University, Budapest, Hungary

Research Focus & Metrics

Academic Career Length

20Years (2007-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
1 April 2011
Verified
Conference Paper
Closed access
Sándor LakiSándor Laki
Sándor Laki
PMPeter Matray
Peter Matray
PHPeter Haga
Peter Haga
TSTamas Sebok
Tamas Sebok
ICIstvan Csabai
Istvan Csabai
GVGabor Vattay
Gabor Vattay
The localization of Internet hosts opens space for a wide scope of applications, from targeted, location aware content provision to localizing illegal content. In this paper we present a novel probabilistic approach, called Spotter, for estimating the geographic position of Internet devices with remarkable precision. While the existing methods use landmark specific calibration for building their internal models we show that the delay-distance data follow a generic distribution for each landmark. Hence, instead of describing the delay-distance space in a landmark specific manner our proposed method handles all the calibration points together and derives a common delay-distance model. This fundamental discovery indicates that, in contrast to prior techniques, Spotter is less prone to measurement errors and other anomalies such as indirect routing. To demonstrate the robustness and the accuracy of Spotter we test the performance on PlanetLab nodes as well as on a more realistic reference set collected by CAIDA explicitly for geolocation comparison purposes. To the best of our knowledge, we are the first to use this novel ground truth containing over 23000 network routers with their geographic locations.

17 December 2009 in Computer Networks
Verified
Journal Article
Closed access
Sándor LakiSándor Laki
Sándor Laki
PMP. Mátray
P. Mátray
PHP. Hága
P. Hága
ICIstvan Csabai
Istvan Csabai
GVGabor Vattay
Gabor Vattay

1 June 2011
Verified
Conference Paper
Closed access
BHBela Hullar
Bela Hullar
Sándor LakiSándor Laki
Sándor Laki
AGAndras Gyorgy
Andras Gyorgy
To manage and monitor their networks in a proper way, network operators are often interested in identifying the applications generating the traffic traveling through their networks, and doing it as fast (i.e., from as few packets) as possible. State-of-the-art packet-based traffic classification methods are either based on the costly inspection of the payload of several packets of each flow or on basic flow statistics that do not take into account the packet content. In this paper we consider the intermediate approach of analyzing only the first few bytes of the first (or first few) packets of each flow. We propose automatic, machine-learning-based methods achieving remarkably good early classification performance on real traffic traces generated from a diverse set of applications (including several versions of P2P TV and file sharing), while requiring only limited computational and memory resources.

25 August 2022 in IEEE Transactions on Mobile Computing
Verified
Journal Article
Closed access
SSSuneet Kumar Singh
Suneet Kumar Singh
Christian Esteve RothenbergChristian Esteve Rothenberg
Christian Esteve Rothenberg
JLJonatan Langlet
Jonatan Langlet
AKAndreas Kassler
Andreas Kassler
PVPeter Voros
Peter Voros
GPGergely Pongracz
Gergely Pongracz
This paper focuses on hybrid pipeline designs for User Plane Function and next-generation NodeB leveraging target-specific features and an insightful discussion of P4 and target challenges and limitations. The entire or disaggregated UPF runs on P4 targets and allocates packet processing data paths in P4 hardware or DPDK/x86 software based on flow characteristics (e.g., heavy hitters) and QoS requirements (e.g., low-latency slices). For the hybrid gNodeB, most packet processing is executed in commodity Tofino hardware, while unsupported functions such as Automatic Repeat Request and cryptography are performed in DPDK/x86. We show that our hybrid UPF improves the scalability by 18× and reduces latency up to 50%. The results also suggest that careful traffic allocation to pipeline targets is required to optimize each target's strength and avoid processing delays. Finally, we demonstrate a QoS-oriented application of the hybrid UPF and present gNodeB buffer service benchmarks.

24 March 2012 in Computer Networks
Verified
Journal Article
Closed access
PMPéter Mátray
Péter Mátray
PHPéter Hága
Péter Hága
Sándor LakiSándor Laki
Sándor Laki
GVGabor Vattay
Gabor Vattay
ICIstvan Csabai
Istvan Csabai

24 November 2020 in IEEE Transactions on Network and Service Management
Verified
Journal Article
Closed access
JVJonathan Vestin
Jonathan Vestin
AKAndreas Kassler
Andreas Kassler
Sándor LakiSándor Laki
Sándor Laki
GPGergely Pongracz
Gergely Pongracz
Industrial Internet of Things (I-IoT) applications require a large number of sensor data to be processed under tight delay and jitter constraints. In such applications, flexible event detection and fast reaction to critical events is an important building block. Traditional approaches use either proprietary networks and dedicated hardware or transmit sensor data towards processing elements in the Cloud or at the Network Edge, using distributed stream processing frameworks. For scalability, a large number of servers are needed and processing on commodity CPUs typically involves high and unpredictable latency. In this paper, we explore how programmable data planes can be used to detect events flexibly and trigger customized and programmable actions directly from the switch program or the programmable network interface card (SmartNIC). We present FastReact-PS, an event-based publish/subscribe I-IoT processing framework in P4 language, which can be flexibly customized from the control plane. Together with stateful processing, FastReact-PS supports windowed time series analysis as well as complex event detection and processing based on boolean logic directly in the data plane of newly emerging programmable networking devices. The logic can be adjusted dynamically from the control plane without the need for recompilation. We implement FastReact-PS in P4 and evaluate it on both a SmartNIC and a DPDK-based software switch running in user space. Our evaluation shows that the latency is reduced by one order of magnitude compared to end-host based approaches at significantly lower jitter while being scalable to processing up to 11 million events per second.