Modeling and Evaluating NFV-Enabled Network Services under Different Availability Modes

Jiang

IEEE Trans. Netw. Serv. Manage.

2021

Self Cite

Network Function Virtualization enables network operators to modernize their networks with greater elasticity, network programmability, and scalability. Exploiting these advantages requires new and specialized designs for management, automation, and orchestration systems which are capable of reliably operating and handling new elements such as virtual functions, virtualized infrastructures, and a whole new set of relationships among them. Operations such as resource allocation, instantiation, monitoring, scaling, or termination of virtual functions are key lifecycle operations that NFV management and orchestration (NFV-MANO) frameworks need to correctly perform. Failures of the NFV-MANO prevent the network ability to respond to new service requests or events related to the normal lifecycle operation of network services. Thus, it is important to ensure robustness and high availability of the MANO framework. This paper adopts a model-driven approach to predict the availability of the NFV-MANO and assess the impact that different failure modes have. We propose different models, based on Stochastic Activity Networks (SANs), which abstract various MANO deployment configurations, inspired by current containerized open-source MANO implementations. Moreover, we integrate software rejuvenation and investigate the trade-off between its associated overhead and system availability increase. An extensive experimental campaign with fault-injection techniques on a real-life MANO implementation allows to derive a number of realistic recovery parameters. The case studies are used to quantitatively evaluate the steady-state availability and identify the most important parameters influencing system availability for the different deployment configurations.

Section: Related Workmentioning

confidence: 99%

Model-Driven Availability Assessment of the NFV-MANO With Software Rejuvenation

Jiang

IEEE Trans. Netw. Serv. Manage.

2021

Self Cite

“…In a more recent study [17], a composed availability model of an NFV service, based on SANs, is proposed. Each VNF, composing the network service, is considered as a loadsharing cluster and the authors propose separate models for various redundancy mechanisms called Availability Modes and investigate the impact that a faulty orchestrator has on the service availability.…”

Section: Related Workmentioning

confidence: 99%

“…We performed a sensitivity analysis to determine which of the parameters have the highest impact on the steady-state availability of the Manager configuration. The SAN model parameters are retrieved from previous literature [17]- [19] and are illustrated in Table I. They represent the reference values and given these parameters, the achieved MANO availability is presented in Table II, together with its component availabilities where the latter are derived from individual dynamics, i.e., not influenced by underlying component failures.…”

Section: A Manager Configuration: Sensitivity Analysismentioning

confidence: 99%

On the Resilience of the NFV-MANO: An Availability Model of a Cloud-native Architecture

Jiang

2020 16th International Conference on the Design of Reliable Communication Networks DRCN 2020

2020

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With Network Function Virtualization (NFV), the management and orchestration of network services require a new set of functionalities to be added on top of legacy models of operation. Due to the introduction of the virtualization layer and the decoupling of the network functions and their running infrastructure, the operation models need to include new elements like virtual network functions (VNFs) and a new set of relationships between them and the NFV Infrastructure (NFVI). The NFV Management and Orchestration (MANO) framework plays the key role in managing and orchestrating the NFV infrastructure, network services and the associated VNFs. Failures of the MANO hinders the network ability to react to new service requests or events related to the normal lifecycle operation of network services. Thus, it becomes extremely important to ensure a high level of availability for the MANO architecture. The goal of this work is to model, analyze, and evaluate the impact that different failure modes have on the MANO availability. A model based on Stochastic Activity Networks (SANs), derived from current standard-compliant microservice-based implementations, is proposed as a case study. The case study is used to quantitatively evaluate the steady-state availability and identify the most important parameters influencing the system availability for different deployment configurations.

“…In a more recent study [10], a composed availability model of an NFV service, based on SANs, is proposed. Each VNF, composing the network service, is considered as a load-sharing cluster and the authors propose separate models for various redundancy mechanisms called Availability Modes.…”

Section: Related Workmentioning

confidence: 99%

“…A number of previous works have quantified the availability of NFV-oriented services, either in "general" terms or by selecting specific NFV service use cases [8], [9], [10]. Nevertheless, none of these works have performed an exhaustive assessment of NFV service availability since they lack key service elements like physical network links or forwarding/routing devices which are essential networking elements inter-connecting VNFs composing a service chain.…”

Section: Introductionmentioning

confidence: 99%

Network-Aware Availability Modeling of an End-to-End NFV-Enabled Service

Nencioni

IEEE Trans. Netw. Serv. Manage.

2019

Self Cite

Network Function Virtualization (NFV) represents a key shift in nowadays network service provisioning by entailing higher flexibility, elasticity, and programmability of network services. Dependability is one of the main aspects that need to be investigated and tackled in order to profitably use NFV in the future. The main objective of this paper is to propose a comprehensive approach to estimate the end-to-end NFV-deployed service availability and present a quantitative assessment of the network factors that affect the availability of the service provided by an NFV architecture. To achieve this goal, we adopted a two-level availability model where i) the low level considers the network topology structure and NFV connectivity requirements through the definition of the system structure function based on minimal-cut sets and ii) the higher level examines dynamics and failure modes of network and NFV elements through stochastic activity networks. By using the proposed model, we have carried out an extensive sensitivity analysis to identify the impact on the service availability of the different service elements involved in the delivery, and their deployment across the network. The results highlight the significant impact that network nodes have on the end-to-end network service. Less robust network nodes may reduce the availability of an NFV-enabled service by more than one order of magnitude even though NFV elements like VNFs or MANO are provided with redundancy. Moreover, the results show that adopting an SDN-integrated network degrades the service availability and increases the vulnerability of the network service to SDN controllers unless adequately protected.