IMDEA Networks Institute Digital Repository
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Prediction-based Techniques for the Optimization of Mobile Networks
Get PDFMobile cellular networks are complex system whose behavior is characterized by the superposition of several random phenomena, most of which, related to human activities, such as mobility, communications and network usage. However, when observed in their totality, the many individual components merge into more deterministic patterns and trends start to be identifiable and predictable.
In this thesis we analyze a recent branch of network optimization that is commonly referred to as anticipatory networking and that entails the combination of prediction solutions and network optimization schemes. The main intuition behind anticipatory networking is that knowing in advance what is going on in the network can help understanding potentially severe problems and mitigate their impact by applying solution when they are still in their initial states. Conversely, network forecast might also indicate a future improvement in the overall network condition (i.e. load reduction or better signal quality reported from users). In such a case, resources can be assigned more sparingly requiring users to rely on buffered information while waiting for the better condition when it will be more convenient to grant more resources.
In the beginning of this thesis we will survey the current anticipatory networking panorama and the many prediction and optimization solutions proposed so far. In the main body of the work, we will propose our novel solutions to the problem, the tools and methodologies we designed to evaluate them and to perform a real world evaluation of our schemes.
By the end of this work it will be clear that not only is anticipatory networking a very promising theoretical framework, but also that it is feasible and it can deliver substantial benefit to current and next generation mobile networks. In fact, with both our theoretical and practical results we show evidences that more than one third of the resources can be saved and even larger gain can be achieved for data rate enhancements.Telematics EngineeringUniversidad Carlos III de Madrid, Spainpu
Ads versus Regular Contents: Dissecting the Web Hosting Ecosystem
Get PDFAds (advertisements) have become a common source of revenues for websites and transformed the web hosting ecosystem. This paper reports an extensive measurement-based study of web hosting with an explicit focus on differences in the hosting of ads versus regular contents. Using a VPN (Virtual Private Network) service and 22,040 open recursive DNS (Domain Name System) resolvers, we collect contents of top country-specific websites in 52 countries around the globe and characterize the hosting infrastructures. While we observe that ads employ more servers for broader load distribution, replication is local for ads and global for regular contents. Our results clearly show that transit ASes (Autonomous Systems), including the tier-1 networks, diversify their economic roles and prominently provide web hosting. A small number of ASes dominate heavily in the byte volume of hosted contents, with the top hosts being different for ads and regular contents. Compared to ASes and organizations, the distribution of hosting countries is even more heavily skewed, with the USA consistently taking the overwhelmingly dominant position. While ads have shorter response times, their download times are longer because websites are developed to serve requests for regular contents with a higher priority.TRUEpu
5G innovations for new business opportunities
No full text5G is the next generation mobile network that enables
innovation and supports progressive change across all
vertical industries and across our society. Through its
Radio Access Network (RAN) design and its orchestrated
end-to-end architecture, it has the potential to boost innovation and generate economic growth in the European economy. The 5G service models support agility and dynamicity, thereby impacting the granularity, duration and trustworthiness of business relationships. The ability to combine private and public networks and data centres across multiple domains in a secure and controlled way facilitates collaborative business processes. It reshapes the digital business ecosystem with new value chains linking stakeholders from the telecommunications world and the vertical industries in win-win situations. New stakeholders emerge in this evolved ecosystem, for example cloud companies and software houses that profit from the cloudification and virtualization of the infrastructure, and brokers that facilitate sharing of spectrum and trading of connectivity and processing resources. Small and medium-sized enterprises and start-ups are able to embed 5G in their innovative products and services for existing and new customers and markets, leveraging on the Anything as a Service (XaaS) model.TRUEpu
Optimising 5G Infrastructure Markets: The Business of Network Slicing
Get PDFIn addition to providing substantial performance enhancements, future 5G networks will also change the mobile
network ecosystem. Building on the network slicing concept, 5G allows to “slice” the network infrastructure into separate logical networks that may be operated independently and targeted at specific services. This opens the market to new players: the infrastructure provider, which is the owner of the infrastructure, and the tenants, which may acquire a network slice from the infrastructure provider to deliver a specific service to their customers. In this new context, we need new algorithms for the allocation of network resources that consider these new players. In this paper, we address this issue by designing an algorithm for the admission and allocation of network slices requests that (i) maximises the infrastructure provider’s revenue and (ii) ensures that the service guarantees provided to tenants are satisfied. Our key contributions include: (i) an analytical model for the
admissibility region of a network slicing-capable 5G Network, (ii) the analysis of the system (modelled as a Semi-Markov Decision Process) and the optimisation of the infrastructure provider’s revenue, and (iii) the design of an adaptive algorithm (based on Q-learning) that achieves close to optimal performance.TRUEpu
Investigating the Causes of Congestion on the African IXP Substrate
Get PDFThis paper was accepted for publication on July 28, 2017. The camera-ready version was submitted on September 28, 2017. The program of the conference is available at http://conferences.sigcomm.org/imc/2017/program/The goal of this work is to investigate the prevalence, causes, and impact of congestion on the African IXP substrate. Towards this end, we deployed Ark probes (within networks peering) at six African IXPs and ran the time-sequence latency probes (TSLP) algorithm, thereby collecting latency measurements to both ends of each mapped AS link for a whole year. We were able to detect congestion events and quantify their periods and magnitudes at four IXPs. We then verified the events and investigated the causes by interviewing the IXP operators. Our results show that only 2.2% of the discovered IP links experienced (sustained or transient) congestion during our measurement period. Our findings suggest the need for ISPs to carefully monitor the provision of their peering links, so as to avoid or quickly mitigate the occurrence of congestion. Regulators may also define the maximum level of packet loss in those links to provide some protection to communications routed through local IXPs.TRUEpu
Zero Overhead Device Tracking in 60 GHz Wireless Networks using Multi-Lobe Beam Patterns
Get PDFMillimeter-wave devices must use highly directional antennas to achieve GBit/s data rates over reasonable distances due to the high path loss. As a consequence, it is important to precisely align the antenna beams between sender and receiver. Even minor movement or rotation of a device can result in beam misalignment and thus a strong performance degradation. Existing work as well as standards such as IEEE 802.11ad tackle this issue by means of antenna sector probing. This comes at the expense of a significant overhead, which may significantly reduce the performance of millimeter-wave communication, particularly in mobile scenarios. In this paper, we present a mechanism that can track both movement and rotation of 60 GHz mobile devices with zero overhead. To this end, we transmit part of the preamble of each packet using a multi-lobe beampattern. Our approach does not require any additional control messages and is backward compatible with 802.11ad. We implement our scheme on a 60 GHz testbed using phased antenna arrays, and show that we reduce the angle error to less than 5◦ in most cases. We also perform simulations to validate our approach in a wide range of scenarios, achieving up to 2× throughput gain.TRUEpu
A Topology-Independent TDMA MAC Policy for Safety Applications in Vehicular Networks
Get PDFThe problem of accessing the medium to support safety applications in vehicular networks is challenging, when
vehicles’ mobility increases and time constraints become tight. In such environments, and particularly for vehicular-to-vehicular communication where safety is the main concern, time delay bounded data packet delivery is a prerequisite. Consequently, topology-independent MAC policies that guarantee a number of successful transmissions independently of the underlying topology, can be employed as a suitable choice for the particular vehicular environment. One such policy is revisited in this paper and its performance is demonstrated against VeMAC – a well-established MAC protocol in the area of vehicular networks – using simulation results. As it is shown in this paper, throughput under the considered topology-independent policy remains comparable to that of VeMAC whereas the number of retransmissions are significantly reduced leading to a reduced time delay.TRUEpu
Throughput Optimization with Latency Constraints
Get PDFModern datacenters are increasingly required
to deal with latency-sensitive applications. A major question here is how to represent latency in desired objectives.
Incorporation of multiple traffic characteristics (e.g., packet values and required processing requirements) significantly increases the complexity of buffer management policies. In this work, we consider weighted throughput optimization (total transmitted value) in the setting where every incoming packet is branded with intrinsic value, required processing, and slack (an offset from the arrival time when a packet should be transmitted), and the buffer is
unbounded but effectively bounded by slacks. We introduce
a number of algorithms based on priority queues and show
that they are non-competitive; then we introduce a novel
algorithm based on emulating a stack and prove a constant
upper bound on its competitive ratio that tends to 3 as the
slack-to-work ratio increases. We support our results with a
comprehensive evaluation study on CAIDA network traces.TRUEpu
Network Slicing to Enable Scalability and Flexibility in 5G Mobile Networks
Get PDFWe argue for network slicing as an efficient solution that addresses the diverse requirements of 5G mobile networks, thus providing the necessary flexibility and scalability associated with future network implementations. We elaborate
on the challenges that emerge when designing 5G networks based on network slicing. We focus on the architectural aspects associated with the coexistence of dedicated as well as shared slices in the network. In particular, we analyze the realization options of a flexible radio access network
with focus on network slicing and their impact on the design of 5G mobile networks. In addition to the technical study, this article provides an investigation of the revenue potential of network slicing, where the applications that originate from this concept and the profit capabilities
from the network operator’s perspective are put forward.pu