Design, implementation and experimental evaluation of a network-slicing aware mobile protocol stack

Mención Internacional en el título de doctorWith the arrival of new generation mobile networks, we currently observe a paradigm shift, where monolithic network functions running on dedicated hardware are now implemented as software pieces that can be virtualized on general purpose hardware platforms. This paradigm shift stands on the softwarization of network functions and the adoption of virtualization techniques. Network Function Virtualization (NFV) comprises softwarization of network elements and virtualization of these components. It brings multiple advantages: (i) Flexibility, allowing an easy management of the virtual network functions (VNFs) (deploy, start, stop or update); (ii) efficiency, resources can be adequately consumed due to the increased flexibility of the network infrastructure; and (iii) reduced costs, due to the ability of sharing hardware resources. To this end, multiple challenges must be addressed to effectively leverage of all these benefits. Network Function Virtualization envisioned the concept of virtual network, resulting in a key enabler of 5G networks flexibility, Network Slicing. This new paradigm represents a new way to operate mobile networks where the underlying infrastructure is "sliced" into logically separated networks that can be customized to the specific needs of the tenant. This approach also enables the ability of instantiate VNFs at different locations of the infrastructure, choosing their optimal placement based on parameters such as the requirements of the service traversing the slice or the available resources. This decision process is called orchestration and involves all the VNFs withing the same network slice. The orchestrator is the entity in charge of managing network slices. Hands-on experiments on network slicing are essential to understand its benefits and limits, and to validate the design and deployment choices. While some network slicing prototypes have been built for Radio Access Networks (RANs), leveraging on the wide availability of radio hardware and open-source software, there is no currently open-source suite for end-to-end network slicing available to the research community. Similarly, orchestration mechanisms must be evaluated as well to properly validate theoretical solutions addressing diverse aspects such as resource assignment or service composition. This thesis contributes on the study of the mobile networks evolution regarding its softwarization and cloudification. We identify software patterns for network function virtualization, including the definition of a novel mobile architecture that squeezes the virtualization architecture by splitting functionality in atomic functions. Then, we effectively design, implement and evaluate of an open-source network slicing implementation. Our results show a per-slice customization without paying the price in terms of performance, also providing a slicing implementation to the research community. Moreover, we propose a framework to flexibly re-orchestrate a virtualized network, allowing on-the-fly re-orchestration without disrupting ongoing services. This framework can greatly improve performance under changing conditions. We evaluate the resulting performance in a realistic network slicing setup, showing the feasibility and advantages of flexible re-orchestration. Lastly and following the required re-design of network functions envisioned during the study of the evolution of mobile networks, we present a novel pipeline architecture specifically engineered for 4G/5G Physical Layers virtualized over clouds. The proposed design follows two objectives, resiliency upon unpredictable computing and parallelization to increase efficiency in multi-core clouds. To this end, we employ techniques such as tight deadline control, jitter-absorbing buffers, predictive Hybrid Automatic Repeat Request, and congestion control. Our experimental results show that our cloud-native approach attains > 95% of the theoretical spectrum efficiency in hostile environments where stateof- the-art architectures collapse.This work has been supported by IMDEA Networks InstitutePrograma de Doctorado en Ingeniería Telemática por la Universidad Carlos III de MadridPresidente: Francisco Valera Pintor.- Secretario: Vincenzo Sciancalepore.- Vocal: Xenofon Fouka

POSENS: a practical open source solution for end-to-end network slicing

Network slicing represents a new paradigm to operate mobile networks. With network slicing, the underlying infrastructure is "sliced" into logically separate networks which can be customized to the specific needs of their tenant. Hand-on experiments on this technology are essential to understand its benefits and limits, and to validate the design and deployment choices. While some network slicing prototypes have been built for the radio access networks (RANs), leveraging on the wide availability of radio hardware and open source software, there is currently no open source suite for end-to-end network slicing available to the research community. In this paper we fill this gap by developing an end-to-end network slicing protocol stack, POSENS, which relies on a slice-aware shared RAN solution. We design the required algorithms and protocols, and provide a full implementation leveraging on state-of-the-art software components. We validate the effectiveness of POSENS in achieving tenant isolation and network slices customization, showing that no price in performance is paid to this end. We believe that our tool will prove very useful to researchers and practitioners working on this novel architectural paradigm.This work has been performed in the framework of the H2020-ICT-2014-2 project 5G NORMA (Grant Agreement No. 671584) and within the 5G-MoNArch project, part of the Phase II of the 5th Generation Public Private Partnership (5G-PPP) program partially funded by the European Commission within the Horizon 2020 Framework Program

Design and validation of a multi-service 5G network with QoE-aware orchestration

Proceeding of: WiNTECH '18: 12th International Workshop on Wireless Network Testbeds, Experimental Evaluation & CharacterizationWhile the work on architectural and algorithmic solutions for 5G has reached a good maturity level, the experimental work lags behind, in particular on the development of open source solutions. In this paper, we describe our implementation experiences when deploying a small-scale multi-service network prototype, used to demonstrate some selected advanced features of 5G Networking. We describe our implementation experiences supporting two heterogeneous services over two independent slices, namely, video streaming and augmented reality, showcasing key features such as multi-slice orchestration, RAN slicing and support for local breakout. While the applications running the services rely on proprietary code, the core of our implementation is completely open-source.This work was supported by the H2020 5G-MoNArch project (grant agreement no. 761445), by the Spanish Ministry of Economy and Competitiveness through the 5G-City project (TEC2016-76795-C6-3-R) and by the Madrid Regional Government through the TIGRE5-CM Program under Grant S2013/ICE-2919

Nuberu : Reliable RAN Virtualization in Shared Platforms

RAN virtualization will become a key technology for the last mile of next-generation mobile networks driven by initiatives such as the O-RAN alliance. However, due to the computing fluctuations inherent to wireless dynamics and resource contention in shared computing infrastructure, the price to migrate from dedicated to shared platforms may be too high. Indeed, we show in this paper that the baseline architecture of a base station¿s distributed unit (DU) collapses upon moments of deficit in computing capacity. Recent solutions to accelerate some signal processing tasks certainly help but do not tackle the core problem: a DU pipeline that requires predictable computing to provide carrier-grade reliability. We present Nuberu, a novel pipeline architecture for 4G/5G DUs specifically engineered for non-deterministic computing platforms. Our design has one key objective to attain reliability: to guarantee a minimum set of signals that preserve synchronization between the DU and its users during computing capacity shortages and, provided this, maximize network throughput. To this end, we use techniques such as tight deadline control, jitter-absorbing buffers, predictive HARQ, and congestion control. Using an experimental prototype, we show that Nuberu attains 95% of the theoretical spectrum efficiency in hostile environments, where state-of-art approaches lose connectivity, and at least 80% resource savingsWe would like to thank our shepherd and reviewers for their valuable comments and feedback. This work has been supported by the European Commission through Grant No. 101017109 (DAEMON project) and Grant No. 101015956 (Hexa-X project), and the CERCA Programme/Generalitat de Catalunya

Demo: Nuberu - A Reliable DU DesignSuitable for Virtualization Platforms

We demonstrate Nuberu. The scenario consists of a DU under test (DuT), and one or more DUs sharing computing resources. A dashboard lets us control the type of DuT: Baseline, implemented with vanilla srsRAN, or Nuberu; the number of competing vDUs; and their SNR. A second screen shows real-time metrics: the processing latency of the TBs from each vDU instance; the throughput performance of DuT; the processing latency of DU jobs from DuT; and the ratio of latency constraint violations of DuT jobs. We show how the throughput attained by the baseline DU approach collapses upon sufficiently high computing interference from the competing DUs. Conversely, we show that the DU design introduced in [3] preserves reliability irrespective of the computing interference.This work has been supported by the EC through Grant No. 101017109 (DAEMON) and Grant No. 856709 (5Growth)

SEMPER: a stateless traffic engineering solution for WAN based on MP-TCP

Proceeding of: IEEE International Conference on Communications (ICC 2018)Enterprise Networking has a strong set of requirements in terms of resiliency, reliability and resources usage. With current approaches being based on monolithic and expensive infrastructures using dedicated overlay links, providers are moving to more economical hybrid solutions that encompass private dedicated links with public/regular Internet connections. However, these usually rely on complex, hardware-dependent and/or proprietary Traffic Engineering (TE) solutions, which are computationally costly, in particular for the forwarding nodes. In this paper, we propose SEMPER: a lightweight TE solution based on MP-TCP that, in contrast to other TE solutions, moves the complexity to the endpoints of the connection, and relieves the forwarding elements from complex operations or even maintaining state. As our evaluation shows, SEMPER efficiently makes use of all available paths between the endpoints while maintaining fairness, and properly adapts to variations on the available capacity.This work has been partly supported by the H2020 5GMoNArch project (grant agreement 761445), and by the Madrid Regional Government through the TIGRE5-CM program (S2013/ICE-2919)

On the benefits of bringing cloud-awareness to network virtual functions

Proceeding of: 2018 European Conference on Networks and Communications (EuCNC), June 18-21, Ljubljana, SloveniaWe are currently observing the softwarization of communication networks, where network functions are translated from monolithic pieces of equipment to programs running over a shared pool of computational, storage, and communication resources. As the amount of this resources might vary over time, in this paper we discuss the potential benefits of introducing resource awareness to softwarized network functions. More specifically, we focus on the case of computational elasticity, namely, the ability to endure shortages of computational resources while providing an adequate (although non-ideal) service. We discuss how to enable this ability by re-designing network functions, and illustrate the potential benefits of this approach with a numerical evaluation

DAEMON: A network intelligence plane for 6G networks

Proceedings of: IEEE Global Communications Conference, 04-08 December 2022, Rio de Janeiro, Brazil.While there is a clear trend towards network automation through the usage of Artificial Intelligence (AI) and Machine Learning (ML) solutions, the major reference network architectures are still not natively including all the mechanisms needed to handle Network Intelligence (NI). This paper introduces a novel architecture proposed within the EU-funded DAEMON project, which includes a Network Intelligence Plane (NIP) that natively integrates NI into the network operation, management, and orchestration procedures. We do so by analyzing the gaps in current reference architectures and designing a Network Intelligence Orchestration (NIO) that handles the most important NI-related mechanisms such as lifecycle management, coordination, and data management.This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement no.101017109 "DAEMON"

Orchestration Procedures for the Network Intelligence Stratum in 6G Networks

Proceeding of: 2023 Joint European Conference on Networks and Communications & 6G Summit (EuCNC/6G Summit), 6-9 June 2023, Gothenburg, Sweden. pp.: 347-352.The quest for autonomous mobile networks introduces the need for fully native support for Network Intelligence (NI) algorithms, typically based on Artificial Intelligence tools like Machine Learning, which shall be gathered into a NI stratum. The NI stratum is responsible for the full automation of the NI operation in the network, including the management of the life-cycle of NI algorithms, in a way that is synergic with traditional network management and orchestration framework. In this regard, the NI stratum must accommodate the unique requirements of NI algorithms, which differ from the ones of, e.g., virtual network functions, and thus plays a critical role in the native integration of NI into current network architectures. In this paper, we leverage the recently proposed concept of Network Intelligence Orchestrator (NIO) to (i) define the specific requirements of NI algorithms, and (ii) discuss the procedures that shall be supported by an NIO sitting in the NI stratum to effectively manage NI algorithms. We then (iii) introduce a reference implementation of the NIO defined above using cloud-native open-source tools.This work has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement no. 101017109 “DAEMON”.Publicad

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