The exponential growth in connectivity and computing demand has made Network Function Virtualization Infrastructure (NFVI) a major contributor to global energy consumption. Conventional network and service deployments, whether based on legacy hardware appliances or NFVI stacks, struggle to dynamically provision resources for peak data traffic demand. This results in nearly constant energy consumption, even during low-traffic periods, leading to inefficient resource use. Network softwarization and virtualization have enabled flexible and programmable service deployments, which are beneficial for the rapid and dynamic scaling of network functions. This paper validates energy-aware service and network orchestration with a Zero-touch Network and Service Management (ZSM) framework for the autonomous optimization of computing, network, and power resources from NFVI in a use case focused on connected mobility, and in particular, smart traffic management. By modeling road traffic based on vehicle count and type and 3rd Generation Partnership Project (3GPP) profiles for data formats in vehicular communication scenarios, the ZSM framework adjusts services and resources to service requirements and to actual demand. Experimental validation on the real-life Smart Highway testbed in Antwerp, Belgium, demonstrates a strong correlation between vehicular traffic and power consumption, supporting the hypothesis that adaptive compute and network resource management reduces unnecessary energy use and advances the vision of sustainable and self-optimizing Sixth-Generation (6G) networks.

Despite major advances in Connected and Autonomous Vehicles (CAVs), edge cases such as unmapped construction zones or dense urban areas still require human intervention. Teleoperation, often combined with Level 4 automation, addresses these situations but demands strict network performance i.e., latency below 5 ms, uplink throughput above 25 Mbps, and 99.999% reliability, to ensure safe, responsive control under heavy load. This paper presents a Proof-of-Concept (PoC) 5G Standalone (SA) network supporting end-to-end Network Slicing for teleoperation. The PoC achieves seamless slice isolation across the 5G Core (5GC), Transport Network (TN), and Radio Access Network (RAN), enabling dynamic and cross-domain Network Slicing to meet teleoperation requirements.

This demonstration paper presents a real-life 5G Standalone proof-of-concept showcasing end-to-end network slicing with both inter-slice and intra-slice isolation across the 5G Core, Transport Network, and Radio Access Network domains. The system, based on a smart hospital scenario, highlights a decentralized 5G architecture that aligns slice selection, controlplane, and data-plane mechanisms to guarantee that network resources are securely partitioned across the entire infrastructure. The demonstration highlights the technical implementation of slice orchestration and performance isolation, showing how critical services such as robotic-surgery control or vital-sign sensors maintain guaranteed quality of service even under high load, while less critical services coexist without interference. The proof-of-concept confirms the practical viability of complete end-to-end network slicing for mission-critical applications that demand reliability, confidentiality, and predictable performance.

This paper presents a comprehensive benchmark study of a real-life 5G Standalone (SA) deployment with different Multiple Input Multiple Output (MIMO) configurations (1x1, 2x2, and 4x4) in an indoor office environment. We evaluate the impact of distance, obstacles, and material composition on key performance metrics, including throughput, Reference Signal Received Power (RSRP), Signal-to-Interference-plus-Noise Ratio (SINR), and Rank Indicator (RI). The results demonstrate that while higher-order MIMO configurations can deliver substantial throughput gains under favorable conditions, their effectiveness is fundamentally constrained by environmental factors such as signal attenuation, multipath propagation, and material-induced losses. Our results provide practical guidelines for indoor network planning and optimization, establishing concrete performance baseline for open-source 5G systems in typical office scenarios highlighting the critical importance of site selection.

The real-world deployments of 5G SA networks have highlighted significant challenges, particularly related to signal coverage, leading to performance degradation for enhanced Mobile Broadband (eMBB), Ultra-Reliable Low-Latency Communication (URLLC), and massive Machine-Type Communications (mMTC). To address these challenges and minimize the costs of new infrastructure deployment, Network Sharing among multiple operators has become a viable, cost-effective solution. The 3rd Generation Partnership Project (3GPP) began exploring network sharing in 5G with Release 15, expanding it with an Indirect Network Sharing configuration in Release 19. In this work, we present an Indirect Network Sharing approach that utilizes Network Slicing to create multiple isolated virtual networks on a single physical infrastructure, ensuring resource isolation and efficient management in a multi-operator environment. Our demonstration illustrates how a third-party entity can effectively manage network resources, maintaining isolation and performance quality across different network domains operated by various providers.

5G Standalone (SA) networks introduce a concept of Network Slicing that enables a range of new applications, such as enhanced Mobile Broadband (eMBB), Ultra-Reliable Low-Latency Communication (URLLC), and massive Machine-Type Communications (mMTC). However, despite the promising potential of 5G SA networks, real-world deployments have revealed significant limitations, particularly in terms of signal coverage, resulting in performance degradation for eMBB, URLLC, and mMTC services. To mitigate these challenges and reduce the costs associated with deploying new infrastructure, Network Sharing among multiple operators has emerged as a cost-effective solution. While the 3rd Generation Partnership Project (3GPP) introduced Network Sharing in 5G Release 15 and added an Indirect Network Sharing configuration in Release 19, real-life implementation remains limited due to immature mechanisms and the lack of automated systems for neutral hosts providers to easily onboard new operators and dynamically allocate network resources to meet specific network requirements. In this paper, we explore the application of Network Slicing as a mechanism to deploy Network Sharing among multiple operators, presenting a 5G SA Indirect Network Sharing architecture as proof of concept (PoC). Through our experiment, performed in a real-world and open-source testbed based on O-RAN principles, we demonstrate how applying Network Slicing technology, Neutral Host providers can effectively deploy resource isolation and enable collaboration in a multi-operator environment while guaranteeing service quality to their users.

The diversity of Beyond 5G (B5G)/Sixth-Generation (6G) technologies and the increasing density of Internet-of-Things (IoT) clients are pushing the traditional MANagement and Orchestration (MANO) into more complex scenarios. The European Telecommunications Standards Institute (ETSI) Industry Specification Group (ISG) Zero-touch Network and Service Management (ZSM) has published several documents that present ZSM as a visionary concept, which promises to deliver benefits for BSG and 6G networks, such as increased efficiency in MANO and for tackling the challenges and limitations endured in the transition from human-intervention assisted network management to fully autonomous network management. This work-in-progress paper provides insights into the recent trends in defining and developing ZSM, the efforts towards standardization of its guidelines, coverage of existing solutions that apply the ZSM principles, a discussion about the imperative of its adoption in the domains of the evolving mobile generations and a proposal for its application in a vehicular use case of Smart Traffic Management (STM), where B5G/6G applications are enhanced by a robust ZSM capability of edge resources, to improve the effectiveness of STM.

The paper demonstrates the VITAL-5G platform capabilities to improve the adoption and effectiveness of 5G and beyond solutions within the Transport & Logistic domain by bridging the knowledge gap between industry stakeholders, network experts, and service developers. Therefore, in this paper, we present four distinct capabilities the VITAL-5G platform offers i) Facilitating deployment of vertical service in the 5G network, ii) Real-time monitoring of network and service performance and iii) Advanced failure diagnostics. IV) Utilization of 5G slices. To enhance the adoption and effectiveness of 5G and beyond solutions within the T&L domain, we showcase how the VITAL-5G platform hides the operational complexity from the experimenters, allowing them to express their network, application, and hardware requirements in a human-readable format, while in turn deploying complex services on the 5G SA infrastructure.

In the rapidly evolving Industry 4.0 landscape, the integration of industrial robots and Artificial Intelligence (AI) is revolutionizing the processes involved in storing and managing goods. While these advancements hold the promise of enhancing operational efficiency, they necessitate a robust and high-performing indoor network infrastructure. This demo paper introduces a dynamic network slicing mechanism tailored for Wi-Fi networks, capitalizing on readily available Commercial Off-The-Shelf (COTS) devices, and seamlessly incorporating In-Band Network Telemetry (INT) within a Software Defined Networking (SDN) framework. To effectively navigate the intricacies and uncertainties of network environments, we employ Fuzzy Logic to oversee queueing disciplines (qdisc), which directly influence air-time—the duration a device allocates to transmitting or receiving data over a wireless channel. Through a series of experimental demonstrations, we highlight the effectiveness of our proposed mechanism in maintaining stringent Quality of Service (QoS) standards even in conditions of network saturation. Our solution guarantees uninterrupted and streamlined operations, even in high-demand scenarios

Enhancing communication between Vulnerable Road Users (VRUs) and Unmanned Automated Vehicles (UAVs) has significant potential to improve road safety. The need for this communication is due to the fact that VRUs will no longer be able to establish physical eye contact with UAVs, given the absence of a human driver behind the steering wheel. However, a challenge in the state-of-the-art technologies for Connected, Cooperative, and Automated Mobility (CCAM), i.e. ITS-G5 (IEEE 802.11p) and Cellular Vehicle-to-Everything (C-V2X), is the lack of a unified communication stack that connects all types of users. This is because the current generation of CCAM communication technologies requires dedicated hardware devices that cannot be easily installed on devices carried by VRUs (such as phones or wearables). This paper aims to address this challenge by providing a real-life, sophisticated solution that offers the CCAM communication stack as a Network-as-a-Service (NaaS) in the 5G and Beyond ecosystem. Integration is achieved by relying on the Service Enabler Architecture Layer (SEAL) principles standardised by the 3rd Generation Partnership Project (3GPP). These architectural principles are embedded in the design of Network-Aware Edge Applications (EdgeApps), which are the building blocks of vertical services in 5G and Beyond. This way, any device or user with the capability to connect to 5G will also be able to retrieve important CCAM services from the network by using EdgeApps. In addition, no dedicated CCAM hardware is needed. Furthermore, this paper provides key lessons learned from the challenges encountered in connecting VRUs and UAVs by integrating CCAM into the 5G and Beyond ecosystem. Moreover, we have conducted real-life experiments to evaluate the system-level latency characteristics of the proposed solution and compared them with those of ITS-G5 and C-V2X.

Connected and Automated Vehicles (CAVs) are revolutionizing the automotive industry by improving real-time situational awareness, and road safety. Connectivity and latency are critical for the secure and efficient operation of CAVs. The evolution of Cellular Vehicular-to-Everything (C-V2X) technology, particularly through Long Term Evolution V2X (LTE-V2X) and its successor New Radio-V2X (NR-V2X), is essential to address these challenges. LTE-V2X and NR-V2X are intended to coexist, complementing each other to cover a broad spectrum of vehicular communication needs. However, network overload is a critical issue, which risks severely degrading the performance of V2X applications and compromising road safety. This study delves into the practical implementation of Network Slicing within a real-world 5G environment, incorporating a modular Open Radio Access Network (O-RAN) architecture on the radio side, and Service-Based Architecture (SBA) principles on the core. We present a Network Slicing configuration that deploys a synergy between the 5G Core (5GC) and the Radio Access Network (RAN). Through strategic placement and policy application across multiple User Plane Functions (UPFs), our configuration enhances network performance and reliability for V2X applications. We validate our approach by demonstrating how this setup effectively manages the high demands of diverse and rigorous applications, ensuring the network requirements for enhanced V2X scenarios under various network conditions. Our results highlight the importance of synergy between 5GC and RAN for the application of an efficient network slicing mechanism in NR-V2X networks.

Vehicular communication is a core technology of Intelligent Transportation Systems (ITS). Vehicle-to-vehicle (V2V) communication still needs to develop resilience, such that communication is safe and efficient, in time-critical applications. The radio-based systems, such as cellular V2X (C-V2X) and Dedicated Short Range Communication (DSRC), which are used classically for vehicular communication suffer from performance degradation in traffic scenarios where traffic is dense. In recent years, Line of Sight (LoS) technologies such as Visible Light Communication (VLC) are considered complementary technology to Radio Frequency (RF). VLC utilizes the light-emitting diodes (LEDs) headlamps and tail lights that are standard on modern vehicles to exchange information with the predecessor and subsequent vehicle. This work-in-progress paper highlights the need to combine RF and LoS technologies to improve the stability and reliability of$V2 V$communication. Therefore, we discuss the different LoS and RF technologies, and we present the combinations that can be used for communication. Finally, we propose a hybrid strategy that combines the best properties of individual technologies.

To properly orchestrate challenging services such as those deployed for Vehicle-to-Everything (V2X) use cases, MANO systems need to be intelligent and automated. Network Function Virtualization (NFV) and Machine Learning (ML) provide opportunities for automating MANO operations, and this paper presents our MI-enhAnced Edge Service orchesTRatiOn (MAESTRO) algorithm that makes proactive ML-driven decisions for edge service relocation to ensure Quality of Service (QoS) guarantees for V2X services. Moreover, to validate the effectiveness of our proposed solution, we have performed the experimentation using real-life testbeds for high computing and smart mobility i.e., Smart Highway and Virtual Wall, located in Antwerp and Gent, Belgium. The contribution of our paper is two-fold: i) we study the interrelation between the Key Performance Indicators (KPIs) measured at the vehicle client side, and the infrastructure metrics at the edge computing nodes and ii) we propose and evaluate an ML-based quality-aware algorithm that automates edge service orchestration to decrease average latency while guaranteeing high service availability and reliability.

The shipping sector has become one of the corner-stone aspects of modern production systems, which has been impacting economic growth over the past decades. Its digitalization is expected to make significant improvements in ship control safety and reliability by enabling autonomous operations. Nonetheless, there are still many challenges that need to be thoroughly studied, and in this paper, we focus on one of them, i.e., the communication between barges, ports, and services, as the increased network latency and the limitations on the bandwidth imposed by satellite communications could result in significant risks for accident occurrence. Thus, we present one of the first attempts to leverage the potential of 5G systems for automating barge operations, starting from teleoperation as an enabler of automation, toward creating and validating a cellular-based automated barge control system in a real-life environment.

Vehicular Edge Computing (VEC) brings cloud infrastructure to the vehicular edge, resulting in better performances and avoiding network congestions. In this work-in-progress paper, the benefits of edge computing over cloud computing are discussed in a vehicular environment context, and they are leveraged by creating a Cooperative, Connected and Automated Mobility (CCAM) performance measurement framework. This measurement tool can follow vehicles by moving across different devices, enabling measurements on Key Performance Indicators (KPIs) using edge computing. We already used this tool to evaluate latencies of both a stationary and driving vehicle, moving over the Smart Highway testbed in Antwerp, Belgium. When driving, smart-edge-following algorithms can be deployed to choose the nearest Road Side Unit (RSU) using broadcasted Cooperative Awareness Messages (CAMs) of the vehicle. While driving on the Smart Highway, the application monitors important performance metrics such as throughput, latency, packet loss, packet delivery rate and more. We compare short-range vehicular communications technologies on the Smart Highway (ITS-G5 and LTE-V2X PC5) against the cellular. Our preliminary results demonstrate the benefits in terms of latency by using short-range communications technologies in VEC applications. These results validate that moving applications to the edge is truly beneficial, since our results confirmed up to 90% lower latency using ITS-G5, up to 50% using LTE-V2X PC5. Future deployments of 5G in the Smart Highway are planned, which would further improve the performance edge computing technologies.

The 5G ecosystem is comprised of the cellular 5G System, as well as a managed and orchestrated infrastructure providing virtualized network and service functions. The automotive industry with its stringent requirements for connected vehicles is a promising and yet challenging consumer of such 5G ecosystem. Deployment of service instances at distributed cloud resources of cellular network infrastructure edges enables localized low-latency access to these services from moving vehicles but comes along with challenges, such as the need for fast reconfiguration of the distributed deployment according to mobility pattern and associated service and resource demand. In this paper, we investigate a solution for the collaborative orchestration of services for Connected, Cooperative and Automated Mobility (CCAM) within such 5G ecosystem. A key objective is the service continuity for a highly dynamic automotive scenario, achieved by the associated management and orchestration of these services in distributed edge clouds. The proposed solution leverages a multi-tier orchestration system as well as localized management and protocol operations for collaborative edge resources. By means of both analytical and experimental evaluations, the paper draws conclusions on the gain in accelerating orchestration decisions and enforcements, while balancing associated protocol and computational load over the highly distributed and multi-layered orchestration system.

Next-generation mobile networks are expected to flaunt highly (if not fully) automated management. To achieve such a vision, Artificial Intelligence (AI) and Machine Learning (ML) techniques will be key enablers to craft the required intelligence for networking, i.e., Network Intelligence (NI), empowering myriad of orchestrators and controllers across network domains. In this paper, we elaborate on the DAEMON architectural model, which proposes introducing a NI Orchestration layer for the effective end-to-end coordination of NI instances deployed across the whole mobile network infrastructure. Specifically, we first outline requirements and specifications for NI design that stem from data management, control timescales, and network technology characteristics. Then, we build on such analysis to derive initial principles for the design of the NI Orchestration layer, focusing on (i) proposals for the interaction loop between NI instances and the NI Orchestrator, and (ii) a unified representation of NI algorithms based on an extended MAPE-K model. Our work contributes to the definition of the interfaces and operation of a NI Orchestration layer that foster a native integration of NI in mobile network architectures.

In this paper we demonstrate a framework to support research on Cooperative Awareness Messages (CAMs) through a monitoring dashboard, deploying a portable environment named CAM Application Framework (CAMAF); it manages the received CAMs and updates a corresponding specific monitor for each active Cooperative Intelligent Transportation System (C-ITS) entity. Each monitor is configurable by choosing CAM fields and making or changing algorithms to display the desired information. We have tested our proposal in a C-ITS testbed with real live traffic in the SmartHighway localted in Antwerp, Belgium.

The plethora of heterogeneous and diversified services in 5G and beyond requires from networks to be flexible, adaptable, and programmable, i.e., to be able to correspondingly adapt to changes. As human intervention might significantly increase delays in MANagement and Orchestration (MANO) operations, automation and intelligence become imperative for orchestrating services and resources, especially the ones with stringent requirements for latency and capacity, such as Vehicle-to-Everything (V2X) services. As virtualization and Artificial Intelligence (AI) promise to mitigate those challenges towards enabling true automation in MANO operations, in this paper we present our effort towards building and fully utilizing the real-life testbeds, such as Smart Highway and Virtual Wall, located in Belgium, to conduct realistic experimentation and validation of distributed orchestration intelligence in a dynamic network such as V2X system.

As manual Management and Orchestration (MANO) of services and resources might delay the execution of MANO operations and negatively impact the performance of 5G and beyond Vehicle-to-Everything (V2X) services, applying AI in MANO to enable automation and intelligence is an imperative. The Network Function Virtualization (NFV), Software Defined Networking (SDN), and Artificial Intelligence (AI), could all together mitigate those challenges, and enable true automation in MANO operations. Thus, in this demo paper we will showcase the use of real-life testbed environments (Smart Highway and Virtual Wall, Belgium) and the Proof-of-Concept that we build to conduct realistic experimentation and validation of intelligent and distributed MANO in a dynamic network such as a V2X system.

With the advancements in SDN and NFV, both applications and network functions can be re-designed, and deployed at more appropriate locations. Thanks to the MEC platforms, cloud-alike service deployments are offered to the users/vehicles at closer proximity. However, MEC deployments are usually i) constrained in resources, ii) contain heterogeneous and distributed network and computing resources, and iii) cover narrower region that constrains service continuity due to the high mobility of vehicles. Thus, in this paper, we present our approach on collocating MEC platforms with roadside infrastructure (i.e., RSUs) in order to improve the QoS of infotainment services for vehicles on the smart highway. We tackle both challenges presented above by deploying MEC platforms along the highway, thereby having distributed control over each MEC host in the form of Kubernetes master nodes, and one powerful and yet centralized orchestrator in the cloud. Our approach is one of the earliest attempts to collocate MEC with the RSU, and to test the benefits of the smart application placement in a realistic vehicular environment.

The educational courses that fall into Science, Technology, Engineering and Math (STEM) category require an extensive practical training in laboratories, in order to build and strengthen students’ skills, thereby preparing them for a future job market. In particular, the significant advancements in computer science and engineering press an urgent need to rethink the core of the existing academic courses, their objectives, and the tools for the practical work, due to the need to maintain the balance between the knowledge that academia provides to the students and the actual requirements for students’ future job vacancies. To this end, our educational research includes the design and development of two different types of laboratories, i.e., a low-cost Raspberry Pi-based laboratory, and a laboratory in the cloud, for the practical teaching of the course Distributed systems. In this paper, we present the valuable feedback from our undergraduate students for both types of the aforementioned experimentation approaches, thereby unraveling the pros and cons of both, and analyzing the existing challenges that still need to be properly tackled.

Due to the varying conditions in traffic and resource availability in networks nowadays, maintaining continuity of network service and satisfying QoS and QoE requirements became a challenging task. If considered in a highly diversified environment in terms of technology and administration, it gets even more complicated, and appropriate service and resource management solutions are mandatory. Thus, the aim of this paper is to present our specific perspective of the ongoing European H2020 5G-CARMEN project, addressing the importance of proactive reconfiguration of network services and their migration between different domains. Leveraging 5G technology and MEC platform, our management platform for automated low-latency-aware VNF placement and migration will enable orchestration of network services and resources across different administrative and technology domains.

The computer network industry is preparing for the revolution caused by the virtualization of the network infrastructure. The virtualization of network functions, together with the network programmability, is a fundamental skill-set required in both electrical engineers and computer scientists, which will become even more significant in the upcoming years. Therefore, in this article, we present an educational framework for Service Function Chaining (SFC) practical teaching to undergraduate students aiming to prepare them for future Information and Communication Technologies (ICT) and communication networks market that will demand skillful professionals in the domain. The educational framework was designed for the Network Management course at the University of Antwerp. To structure the content of the framework’s sessions, we explain the fundamental concepts behind the SFC. Moreover, we detail the framework objectives, sessions, and how we plan to evaluate it. We also present facts and works that endorse the hands-on teaching preparing students for the research and development in the new generation communication networks arena. After, we discuss the methodology of the educational framework alignment with joint ACM/IEEE Computer Engineering Curricula for Network Management courses. Next, we present possible outcomes during the course evaluation using the survey. We conclude which this educational framework achieves the necessary core learning outcomes to empower students concerning the practical steps when deploying and managing communication networks and the virtualization techniques which nowadays are being applied.

The combination of 5G and Multi-access Edge Computing (MEC) technologies can bring significant benefits to vehicular networks, providing means for achieving enhanced Quality of Service (QoS), and Quality of Experience (QoE) of wide variety of vehicular applications. Although beneficial in terms of latency reduction, the edge of the architecture for communication networks produces enormous heterogeneity of network services and resources. This challenge becomes even more severe when different administration domains are taken into consideration. Thus, efficient network Management and Orchestration (MANO) of network resources and services are inevitable. As ETSI provided guidelines and standardization for NFV MANO components, the MEC platform can be used to host network services, while MANO systems are in charge of network service management and orchestration. In this paper, we focus on the specific impact that the Virtualized Infrastructure Manager (VIM) has on the performance of the whole MANO system, used for management and orchestration of MEC services and resources in vehicular networks by enabling the on-demand service instantiation, and service teardown. In our testbed-based evaluation, we measured the network service instantiation and termination delays when evaluating: a) OpenStack and Amazon Web Services (AWS) as VIMs for Open Source MANO (OSM), and b) OpenStack and Docker in case of Open Baton. Such performance analysis with a strong experimental component can serve as a baseline for researchers and industry towards exploiting the opportunities that existing MANO solutions provide.

5G has opened up possibilities of introducing new use cases and business models that could not be perceived before. In the context of public safety, 5G offers immense opportunities towards enhancing mission success and situation awareness during emergency management. This paper introduces Back-Situation Awareness (BSA) application enabling early warning/notification to vehicles of an approaching emergency vehicle indicating its presence and the time it will arrive. Such an application is expected to give drivers enough time to create a safety corridor for the emergency vehicle to pass through safely and unhindered. We provide details on the system and application design of the BSA application leveraging Multi-Access Edge Computing (MEC) systems that complement the 5G mobile communication system. An evaluation of the application is provided by using data measurements and indicating the accuracy of the computation and notification of the Estimated Time of Arrival (ETA) based on the ETSI C-ITS protocol messages.

An important aspect of managing multi access point (AP) IEEE 802.11 networks is the support for mobility management by controlling the handover process. Most handover algorithms, residing on the client station (STA), are reactive and take a long time to converge, and thus severely impact Quality of Service (QoS) and Quality of Experience (QoE). Centralized approaches to mobility and handover management are mostly proprietary, reactive and require changes to the client STA. In this paper, we first created an Software-Defined Networking (SDN) modular handover management framework called HuMOR, which can create, validate and evaluate handover algorithms that preserve QoS. Relying on the capabilities of HuMOR, we introduce ABRAHAM, a machine learning backed, proactive, handover algorithm that uses multiple metrics to predict the future state of the network and optimize the load to ensure the preservation of QoS. We compare ABRAHAM to a number of alternative handover algorithms in a comprehensive QoS study, and demonstrate that it outperforms them with an average throughput improvement of up to 139%, while statistical analysis shows that there is significant statistical difference between ABRAHAM and the rest of the algorithms.