IMDEA Networks Institute Digital Repository
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The case for serverless mobile networking
Get PDFThe softwarization of communication networks provides notable benefits, such as flexibility, improved resource efficiency, and commoditization. In exchange, softwarization requires an increased management overhead and the need to re-design network operation. While the mobile networking eco-system is currently adapting this new paradigm with other network-related aspects (e.g., network slicing), cloud computing already addressed such problems with the introduction of serverless architectures, also known as Function as a Service (FaaS). With this approach, the software is decomposed into its minimum building blocks, i.e., functions, maximizing scalability, resource efficiency, and flexibility. In this paper, we analyze the potential adoption of the FaaS paradigm by the mobile networking ecosystem, discussing the implicit advantages, the challenges to address, and some solutions to overcome them.TRUEpu
Performance and Pitfalls of 60 GHz WLANs Based on Consumer-Grade Hardware
Get PDFWireless networks operating in the 60 GHz band have the potential to provide very high throughput but face a number of challenges (e.g., high attenuation, beam training, and coping with mobility) which are widely accepted but often not well understood in practice. Understanding these challenges, and especially their actual impact on consumer-grade hardware is fundamental to fully exploit the high physical layer rates in the 60 GHz band. To this end, we perform an extensive measurement campaign using two commercial off-the-shelf 60 GHz routers in real-world environments. Our results allow us to revisit a range of issues and provide much deeper insights into the reasons for specific performance compared to prior work on performance characterization. Further, our study goes beyond basic link characterization and explores for the first time practical considerations such as coverage and access point deployment. While some of our observations are expected, we also obtain highly surprising insights that challenge the prevailing wisdom in the community. We derive the shortcomings of current commercial 60 GHz devices and the fundamental problems that remain open on the way to fast and efficient 60 GHz networking.pu
A Link Quality Estimation-based Beamforming Training Protocol for IEEE 802.11ay MU-MIMO Communications
Get PDFThe enables an and multiple to determine appropriate directional antenna patterns; to this end, the ap transmits multiple action frames to the stas during the mumimo bft. However, if the are determined to transmit the action frames inefficiently, this could lead to unnecessary transmissions, which could increase the bft time. To mitigate the signaling overhead, the schemes used in our previous work employed awvs, which use multiple beams simultaneously to transmit the action frames. Nevertheless, these existing schemes are still adversely affected by redundant transmissions because these schemes overlook the transmit diversity gain obtained from multi-beam concurrent transmission. Therefore, in this study, we propose a novel transmit antenna configuration scheme that mitigates the signaling overhead by considering the transmit diversity of the channel incurred when multiple beams are used simultaneously. Our proposed scheme determines each candidate awv using multiple beams and efficiently identifies the stas within reach of the corresponding multi-beam concurrent transmission. The numerical and simulation results demonstrate that our proposed scheme shortens the bft time in comparison with existing schemes.pu
Application Optimisation: Workload Prediction and Autonomous Autoscaling of Distributed Cloud Applications
Get PDFOptimisation of (the configuration and deployment of) distributed cloud applications is a complex problem that requires understanding factors such as infrastructure and application topologies, workload arrival and propagation patterns, and the predictability and variations of user behaviour. This chapter outlines the RECAP approach to application optimisation and presents its framework for joint modelling of applications, workloads, and the propagation of workloads in applications and networks. The interaction of the models and algorithms developed is described and presented along with the tools that build on them. Contributions in modelling, characterisation, and autoscaling of applications, as well as prediction and generation of workloads, are presented and discussed in the context of optimisation of distributed cloud applications operating in complex heterogeneous resource environments.TRUEpu
Machine Learning Based Network Analysis using Millimeter-Wave Narrow-Band Energy Traces
Get PDFNext-generation wireless networks promise to provide extremely high data rates, especially exploiting the so-called millimeter-wave frequency range. Gaining information from spectrum usage is becoming important to provide smart adaptation capabilities to future network protocol stacks. Issues such as deafness, misaligned antennas, or blockage may severely impact network performance, and their identification is crucial. Despite the complexity of full analytical models, machine learning techniques are progressively being considered to improve spectrum usage at higher layers. In this paper, we design a signal processing technique that uses narrowband physical layer energy traces, obtained from one or multiple channel sniffers.
The proposed technique utilizes a combination of template matching and an Explicit Duration Hidden Markov Model (EDHMM) to correctly classify frames, while coping with the non-stationarity of the traces. This leads to a protocol level monitor that does not need to decode the channel at the physical layer, but just infers the type of packets that are exchanged based on sub-sampled energy traces. The performance of this framework is evaluated using off-the-shelf mm-wave wireless devices, quantifying its detection performance in the presence of one or multiple sniffers, and assessing the impact of physical layer parameters such as noise power and signal levels.pu
Towards declarative self-adapting buffer management
Get PDFBuffering architectures and policies for their efficient management are one of the core ingredients of network architecture. However, despite strong incentives to experiment with and deploy new policies, opportunities for changing or automatically choosing anything beyond a few parameters in a predefined set of behaviors still remain very limited. We introduce a novel buffer management framework based on machine learning approaches which automatically adapts to traffic conditions changing over time and requires only limited knowledge from network operators about the dynamics and optimality of desired behaviors. We validate and compare various design options with a comprehensive evaluation study.pu
Protecting against Website Fingerprinting with Multihoming
Get PDFAnonymous communication tools, such as Tor, are extensively employed by users who want to keep their web activity private. But recent works have shown that when a local, passive adversary observes nothing more than the timestamp, size and direction (incoming or outgoing) of the packets, it can still identify with high accuracy the website accessed by a user. Several defenses against these website fingerprinting attacks have been proposed but they come at the cost of a significant overhead in traffic and/or website loading time. We propose a defense against website fingerprinting which exploits multihoming, where a user can access the Internet by sending the traffic through multiple networks. With multihoming, it is possible to protect against website fingerprinting by splitting traffic among the networks, i.e., by removing packets from one network and sending them through another, whereas current defenses can only add packets. This enables us to design a defense with no traffic overhead that, as we show through extensive experimentation against state-of-the-art attacks, reaches the same level of privacy as the best existing practical defenses. We describe and evaluate a proof-ofconcept implementation of our defense and show that is does not add significant loading-time overhead. Our solution is compatible with other state-of-the-art defenses, and we show that combining it with another defense further improves privacy.pu
New Alternatives to Optimize Policy Classifiers
No full textGrowing expressiveness of services increases the size of a manageable state at the network data plane. A service policy is an ordered set of classification patterns (classes) with actions; the same class can appear in multiple policies. Previous studies mostly concentrated on efficient representations of a single policy instance. In this work, we study space efficiency of multiple policies, cutting down a classifier size by sharing instances of classes between policies that contain them. In this paper we identify conditions for such sharing, propose efficient algorithms and analyze them analytically. The proposed representations can be deployed transparently on existing packet processing engines. Our results are supported by extensive evaluations.pu
Optimization Methods for Efficient Relay Techniques in Cellular Networks
Get PDFFast advance in the design of 5G cellular networks has motivated a lot of research that addresses challenges given by the explosive growth of traffic burden, the rise of energy consumption constraints, the unprecedentedly high demand for broadband mobile connectivity and guaranteed quality-of-service for end-users. Therefore the appearance of new technologies, system designs and fast network solutions becomes vital to bear such high demand in network infrastructures.
In this context, the wireless relay scenario has emerged as a key enabler to deal with such challenges. Having clever and efficient schemes that allow traffic to follow alternative relayed paths rather than direct delivery from producer to consumer stands as a crucial need to be properly integrated on the 5G and beyond networks. Depending on the kind of relay, we envision different relay paradigms: users aiming to relief the traffic burden enable device-to-device relay systems; flexible relaying for dense wireless backhaul systems powered by directional transmissions needs smart relay to boost spatial reuse that minimizes the amount of time needed for traffic readiness; and the possibility of mounting relays on extremely-mobile devices such as drones turns the air space into an unexplored vast amount of possibilities to properly position aerial relays.
In this thesis, we present practical optimization tools that leverage the mentioned wireless relay paradigms. We derive optimization frameworks that boost important network metrics such as fair traffic delivery, backhaul traffic readiness or network coverage in current cellular networks. We carefully model network features such as traffic paths, consumed energy, user throughput, transmission directionality or link activation cost, among others. Hence, we approach realistic network infrastructures restricted by technical, physical, flow, or fairness constraints. As unavoidable complex mathematical constraints arise that often turn into an NP-Complete problem, we propose lightweight schemes that work in low-degree polynomial time that are able to provide efficient close-to-optimal solutions, as required in current networks operating at tiny time-scales.
The results reported in this thesis show that designing optimization tools that properly identify key opportunities for efficient relay such as best split traffic paths, best directional transmission scheduling or best aerial relay positioning provides very high gains in terms of throughput experience, fast readiness of traffic at the edge nodes or users coverage. Hence, solutions proposed in this thesis comply with implementation requirements as well as guaranteed performance service for desirable integration on current cellular networks.Telematics EngineeringUniversidad Carlos III de Madrid, Spainpu
Filtering Visible Light Reflections with a Single-Pixel Photodetector
Get PDFLight-based positioning systems (LPS) are gaining significant attention as a means to provide localization
with cm accuracy. Many of these systems estimate the object position based on the received light intensity, and work properly in `ideal' environments such as large open spaces without obstructions around the light-emitting diode (LED) and the receiver, where reflections are negligible. In more dynamic environments, such as indoor spaces with moving people and city roads with moving vehicles, materials cause a wide variety of reflections. This causes variations in the received light intensity and, as a consequence, gross localization errors in LPS. We propose a new multipath detection technique for improving LPS that does not require the knowledge of the channel impulse response and then, it is suited
to be implemented in low-cost positioning receivers that use a single-pixel photodetector. To develop our technique, we (i) analyze the statistical properties of non-line-of-sight (NLOS) components, (ii) develop an automated testbed to study the reflections of different types of surfaces and materials, and (iii) design an algorithm to remove the NLOS components affecting
the positioning estimate. Our experimental evaluation shows that, in complex environments, our methodology can reduce the localization error using LEDs up to 93%.TRUEpu