HASFC: a MANO-compliant Framework for Availability Management of Service Chains

Most softwarized telco services are conveniently framed as Service Function Chains (SFCs). Indeed, being structured as a combination of interconnected nodes, service chains may suffer from the single point of failure problem, meaning that an individual node malfunctioning could compromise the whole chain operation. To guarantee "highly available" (HA) levels, service providers are required to introduce redundancy strategies to achieve specific availability demands, where cost constraints have to be taken into account as well. Along these lines we propose HASFC (standing for High Availability SFC), a framework designed to support, through a dedicated REST interface, the MANO infrastructure in deploying SFCs with an optimal availability-cost trade off. Our framework is equipped with: i) an availability model builder aimed to construct probabilistic models of the SFC nodes in terms of failure and repair actions; ii) a chaining and selection module to compose the possible redundant SFCs, and extract the best candidates thereof. Beyond providing architectural details, we demonstrate the functionalities of HASFC through a use case which considers the IP Multimedia Subsystem, an SFC-like structure adopted to manage multimedia contents within 4G and 5G networks

A unifying orchestration operating platform for 5G

5G will revolutionize the way ICT and Telecommunications infrastructures work. Indeed, businesses can greatly benefit from innovation introduced by 5G and exploit the new deep integration between ICT and networking capabilities to generate new value-added services. Although a plethora of solutions for virtual resources and infrastructures management and orchestration already exists (e.g., OpenDaylight, ONOS, OpenStack, Apache Mesos, Open Source MANO, Docker Swarm, LXD/LXC, etc.), they are still not properly integrated to match the 5G requirements. In this paper, we present the 5G Operating Platform (5G-OP) which has been conceived to fill in this gap and integrate management, control and orchestration of computing, storage and networking resources down to the end-user devices and terminals (e.g., smart phone, machines, robots, drones, autonomous vehicles, etc.). The 5G-OP is an overarching framework capable to provide agnostic interfaces and a universal set of abstractions in order to implement seamless 5G infrastructure control and orchestration. The functional structure of the 5G-OP, including the horizontal and vertical interworking of functions in it, has been designed to allow Network Operators and Service Providers to exploit diverse roles and business strategies. Moreover, the functional decoupling of the 5G-OP from the underneath management, control and orchestration solutions allows pursuing faster innovation cycles, being ready for the emergence of new service models

A unifying operating platform for 5G end-to-end and multi-layer orchestration

Heterogeneity of current software solutions for 5G is heading for complex and costly situations, with high fragmentation, which in turn creates uncertainty and the risk of delaying 5G innovations. This context motivated the definition of a novel Operating Platform for 5G (5G-OP), a unifying reference functional framework supporting end-to-end and multi-layer orchestration. 5G-OP aims at integrated management, control and orchestration of computing, storage, memory, networking core and edge resources up to the end-user devices and terminals (e.g., robots and smart vehicles). 5G-OP is an overarching architecture, with agnostic interfaces and well-defined abstractions, offering the seamless integration of current and future infrastructure control and orchestration solutions (e.g., OpenDaylight, ONOS, OpenStack, Apache Mesos, OpenSource MANO, Docker, LXC, etc.) The paper provides also the description of a prototype that can be seen as a simplified version of a 5G-OP, whose feasibility has been demonstrated in Focus Group IMT2020 of ITU-T

Availability Analysis of IP Multimedia Subsystem in Cloud Environments

As of today, telecommunication providers are exploiting the possibilities offered by the cloud paradigm to efficiently decouple physical network resources, like hardware equipment, optical interfaces and cables, from offered services, for instance multimedia content delivery and data storage. Among technologies conceived to implement this paradigm, containerization stands out. It can be considered as an evolution of classic virtualization, where software instances called containers are designed to offer specific network functionalities by relying on a separate infrastructure composed of virtual machines and hardware. In line with this new trend, we characterize, from an availability viewpoint, an IP Multimedia Subsystem (IMS) architecture deployed in a containerized environment (dubbed cIMS), which represents a pivotal part of novel network architectures such as 5G. Firstly, we model the availability of cIMS by employing both Reliability Block Diagram (RBD), to capture logical dependencies among cIMS nodes, and Stochastic Reward Networks (SRN), to characterize individually the probabilistic behavior of each node. Then, also supported by an ad-hoc automated procedure, we carry out an experimental assessment of a typical telecommunication network service satisfying a desired availability constraint, whose results are some feasible cIMS configurations that can be deployed

Availability Assessment of IP Multimedia Subsystem in an NFV-based Environment

Network Function Virtualization (NFV) is considered one of the most influencing concepts in modern telecommunication frameworks, since it has the merit of transposing (and adapting) the virtualization paradigms from the computer world to the networking context. An instance of NFV is known as a Virtual Network Function (VNF), and represents a virtualized abstraction of a network element such as a router, a firewall, a load balancer, deployed in a virtualized environment. Actually, complex infrastructures, such as IP Multimedia Subsystem (IMS), a framework in charge of providing advanced multimedia services, can benefit of a virtualized deployment by implementing its constitutive elements as VNFs. The resulting architecture is a vIMS that, in this work, is characterized in terms of availability. More specifically, relying on a failure/repair model of a generic vIMS entity (modeled as a three-layer structure composed of hardware, hypervisor and software), we propose an availability assessment of the whole system by means of Stochastic Reward Networks framework

Service Function Chaining deployed in an NFV environment: an availability modeling

Nowadays, network and telecommunication operators require flexible and dynamic models to deploy new services in a fast, reliable and cost saving way. The Service Function Chaining (SFC) design is particularly suited to meet such needs, especially in conjunction with the Network Function Virtualization (NFV) paradigm that adds a noteworthy elasticity during the SFC deployment phase. Accordingly, SFC is realized by means of a composition of Virtualized Network Functions (VNFs) aimed at providing some specific services. We consider, from an availability point of view, an SFC-based architecture with an aim to find out the optimal configuration guaranteeing the so-called “five nines” availability requirement, as demanded in the telecommunication systems. The availability analysis is carried out by exploiting a hierarchical model where a Reliability Block Diagram describes high level dependencies in the SFC implementation, while Stochastic Reward Nets are adopted to model the probabilistic behavior of single blocks. In particular, the SFC availability has been evaluated by performing a steady-state analysis, while a sensitivity analysis of some critical parameters allowed us to analyze in depth the whole system robustness

Availability evaluation of the virtualized infrastructure manager in network function virtualization environments

The Network Function Virtualization (NFV) initiative involving the European Telecommunications Standard Institute (ETSI) and a group of telecom companies, started in 2012 aimed at allowing the network operators to deploy a set of services in a reliable, secure and fastway. In fact, just as a physical machine (equipped with operative system, CPU, memory etc.) can be virtualized by exploiting some virtualization frameworks, a network function (e.g. Firewall, IDS, Load Balancer etc.) can be virtualized by exploiting standard hardware resources. Considering that one of the main benefits of an NFV infrastructure is its high availability, this paper focuses on the analysis of the Virtualized Infrastructure Manager (VIM), a core element that is implemented through the OpenStack platform and is aimed at managing the whole NFV rchitecture. In the present work, inspired by OpenStack technology, the authors propose and assess aVIM model composed by three main modules namely: (i) the High-Availability Proxy providing a Load Balancer function, (ii) a Database management System typically implemented in MySQL technology and (iii) a set of core modules called Functional Blocks, aimed at providing some functionalities (authentication, disk images storage etc.) for the whole system. The architecture has been assessed by means of the Stochastic Reward Nets (SRN). In particular, the system availability has been evaluated by performing both a steady-state and transient analysis of SRNs in order to obtain the best system configuration with the “five nines” availability requirement

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