QUIC is a transport-layer protocol that encrypts most headers and all payload data, encapsulating them in UDP to provide security and low latency. However, this encryption and encapsulation pose challenges for kernel-level network and security monitoring. To address this, we present LinkQUIC, the first heuristic-based system that identifies and classifies QUIC traffic at both kernel-space endpoints and middleboxes. LinkQUIC analyzes unencrypted QUIC header fields and leverages gaps in existing QUIC implementations, particularly during connection migration and path changes where behavior does not fully comply with RFC 9000’s privacy-preserving guidelines. Unlike user space tools, By leveraging eBPF, LinkQUIC operates entirely in kernel space without requiring kernel modifications, encryption keys or prior knowledge of specific QUIC deployments. We evaluate LinkQUIC in real-world environments and demonstrate its effectiveness in identifying QUIC traffic, including complex migration scenarios, with minimal overhead.

In the cloud computing era, cross-cloud deployments enable organizations to operate across multiple autonomous cloud platforms, offering advantages such as resilience, cost and performance optimization. However, lateral movement attacks, which are critical in the progression of Advanced Persistent Threats (APTs), pose significant challenges in this environment. This paper proposes a Lateral Movement Identification (LMD) system to identify lateral movement attacks in cross-cloud containerized environments. The LMD system utilizes Dynamic Information Flow Tracking (DIFT) and extended Berkeley Packet Filter (eBPF) sandboxes to monitor and associate network traffic within container host kernel without kernel modification. Our experiments validate the efficiency of the LMD system in tracking ingress and egress traffic, differentiating between multiple simultaneous connections, and maintaining minimal performance overhead.

This work presents a novel approach for managing and orchestrating Virtual Network Functions (VNFs) across cloud domains. We introduce deployable Sidecar VNF (S-VNF) coordinators designed for seamless integration into existing infrastructure, enabling operators to leverage infrastructure services provided by different providers. This approach offers several advantages beyond flexibility: domain-specific adaptation to diverse environments, non-intrusive deployment minimizing disruption to existing NFV Management and Orchestration (MANO) systems, enhanced MANO interoperability, and improved security through proxying and shielding the underlying MANO management interface. Experiments confirm that the delay introduced by our S-VNF coordinators has a negligible impact on overall performance, making it a viable solution for cross-cloud VNF management.

Network Function Virtualization (NFV) is a hot topic in computer networking and aims to replace proprietary, hardware-based networking services with virtualized, cloud-based network functions. However, the current implementation of NFV Management and Orchestration (MANO) often relies on either expensive or high-overhead cloud resources, such as AWS and OpenStack, as the NFV infrastructure (NFVI), which may limit research and deployment in edge computing scenarios. To address this issue, our work proposes a cost-effective solution to set up an NFVI suitable for both testbed research and production edge deployment. We suggest using a cluster of Raspberry Pi (RPi) powered by Canonical Metal-as-a-Service (MAAS) as a bare-metal cloud infrastructure to establish an NFVI for Virtual Network Functions (VNF) deployment from Open-Source MANO (OSM).

We introduce, describe and discuss the potentialities of Moulinog, a tool created during the COVID-19 lockdown, designed to generate individual questionnaires for the remote evaluation of large classrooms. Starting with a list of students and a series of predicates constituting a pool of parametric questions along with rules for their parametrization, Mouling generates a list of individual questionnaires, together with a shell script allowing an easy emailing of the (password-protected) questionnaires to the students. The tool’s use in practice is illustrated on a particular course case for which it has proven to be both useful and time-saving.

Thanks to the fact that Belgium is a densely populated country, and also lags behind in the roll-out of Long Term Evolution (LTE) / 4G, it is still possible to visit areas enjoying different Radio Access Technology (RAT) coverages within a limited territory. This paper reports an analysis of the dataset of web requests collected through a field survey mostly performed in south-western Belgium and northern France. This analysis highlights the impact of Radio Access Network (RAN) conditions (signal strength, mobility) and settings (timers) on the canvas Page Load Time (cPLT).

This paper presents the first steps of our work related to overload control techniques. These techniques are currently under development in the SIP Overload Control (SOC) Internet Engineering Task Force (IETF) Working Group (WG). A preliminary step to this work is to build a realistic test environment.

We present a formal distributed algorithm that can be used for the deployment of arbitrary routing policies in a network infrastructure that attempts to complete the ideas proposed by Griffin et al. We prove that our algorithm is based on a function that satisfies conditions proposed by Bertsekas. These conditions guarantee that the distributed version of the algorithm will converge and yield the same result as a centralized computation of the routing matrix. We also present a prototype in Haskell that illustrates the possibilities of defining policies and general computations on them.

This paper describes an adaptive streaming technique that exploits temporal concatenation of H.264/AVC video bit-streams and uses only standard RTCP reports as feedback mechanism. As a result, common media players like VLC, QuickTime or GStreamer based, can be used in a streaming session with improved viewing experience when accessing video content through bandwidth constrained connections. Further, an original probing technique that uses video packets as probing data has been developed in order to assess whether the available bandwidth allows streaming at a higher bitrate, maximizing thus video quality and user experience. The proposed solution has been tested in real wireless scenarios, showing that video quality can indeed be improved even for standard media players.

This paper presents our sqTM burst mapping algorithm for downlink Mobile WiMAX systems. Based on a treemap visualization algorithm, we introduce a new burst mapping scheme we called sqTM, greatly reducing the amount of wasted slots. We obtained between 60% and 75% reduction compared to some reference algorithms we implemented. These limited wastes are able to provide better cell throughput and larger cell capacities. Unfortunately, sqTM is significantly slower than reference algorithms, but still easily coping with 5 ms frames.

To adapt the transmission schemes in wireless communications, it is useful for the transmitter to have actual knowledge of the channel's behavior. One way to build such knowledge is to predict the future state of the channel from past measurements. This paper presents two MIMO channel predictors, derived from existing SISO ESPRIT-based techniques. With a sampling rate of 4 samples per wavelength, 17 channel observations are sufficient to produce predictions over a few wavelengths in the case of a 4times4 MIMO system operating in a microcell environment. These predictors are quite simple and have limited computational needs.

We discuss here a scheme to improve the Rel'99 UMTS radio resource management. The article focuses on the two different types of transport channel: shared and dedicated. It evaluates the merits of a scheme based on an optimal non real-time session switching between these two kinds of channels. The switching decision may be influenced by several parameters like the downswitch timer's duration, the non-/preemptive split of downswitch timer and the selection of the initial transport channel. Performances of the analysed scheme are evaluated taking into account different metrics: blocking rate, mean packet delay and cell throughput. The results show that an optimal tuning of these three parameters may significantly decrease the number of blocked calls while keeping the other metrics at a satisfactory level.

Based on the end-to-end delay experienced by the user, this paper derives a spreading factor allocation map for the four UMTS traffic classes and for four user profiles with the help of a computer testbed emulating the UTRAN. Using this allocation map, the performance of the UTRAN is measured in terms of cell throughput and blocking rate in different scenarios.

As far as transfer reliability is concerned, the wireless segment of UTRAN is the weakest part of an Internet session. To overcome this imperfection, the RLC protocol features a link-level retransmission mechanism. In this paper, we show by analytical means and computer simulations that for a given Block Error Rate (BLER), the maximum number of RLC transmissions has a very important impact on TCP performance, both Round Trip Time (RTT) and throughput. We extend the link level Automatic Repeat Request model proposed by Peisa et al. (2001) to be able to set a maximum number of RLC transmissions, and with the help of Padhye's TCP throughput model (2000), we determine the corresponding throughput analytically. We also show that, knowing the current BLER, a network operator may tune the maximum number of retransmissions either to reduce the RTT or to increase the throughput.

This paper addresses the derivation of a closed-form expression for the correlation coefficient of a pair of antenna elements at the base station. The closed-form expression is derived for the case of a multimodal truncated Laplacian power azimuth spectrum that impinges on antenna elements exhibiting a directive radiation pattern that is widely used in standardization bodies. To avoid numerical instability, an approximation for small azimuth spreads is presented. The proposed closed-form expression, along with its approximation, is successfully validated against the numerical computation of the correlation coefficient.

Capacity increases promised by multiple-input multiple-output (MIMO) systems mostly depend on the spatial correlation properties of the radio channel. The paper investigates the connection between these properties and the capacity figures. It first derives the correlation coefficient between two antenna elements as a function of their spacing, the power azimuth spectrum (PAS), the azimuth spread (AS) and the mean angle of incidence of the waves, for three different types of PAS, namely uniform, truncated Gaussian and truncated Laplacian. With the help of the established relations, correlated flat-fading MIMO channels are generated, whose capacity performance and effective degrees of freedom (EDOF) are investigated for two power allocation schemes, water-filling and uniform. The impact of channel estimation errors is also evaluated.

Theoretical and experimental studies of multiple-input/multiple-output (MIMO) radio channels are presented. A simple stochastic MIMO model channel has been developed. This model uses the correlation matrices at the mobile station (MS) and base station (BS) so that results of the numerous single-input/multiple-output studies that have been published in the literature can be used as input parameters. The model is simplified to the narrowband channels. The validation of the model is based upon data collected in both picocell and microcell environments. The stochastic model has also been used to investigate the capacity of MIMO radio channels, considering two different power allocation strategies, water filling and uniform and two different antenna topologies, 4/spl times/4 and 2/spl times/4. Space diversity used at both ends of the MIMO radio link is shown to be an efficient technique in picocell environments, achieving capacities within 14 b/s/Hz and 16 b/s/Hz in 80% of the cases for a 4/spl times/4 antenna configuration implementing water filling at a SNR of 20 dB.

A stochastic MIMO radio channel considering (i) polarization diversity and (ii) unbalanced branch power ratio (BPR) is being validated by comparing Monte-Carlo simulations and experimental results using the eigenanalysis as benchmark. Based on results generated by the model, the influence of the BPR on the power gain of the parallel subchannels is presented.