1 A Model-based Approach Towards Real-time Analytics in NFV Infrastructures Raffaele Bolla, Roberto Bruschi, Franco Davoli and Jane Frances Pajo Abstract—Network Functions Virtualization (NFV) has recently gained much popularity in the research scene for the flexibility and programmability that it will bring with the software implementation of network functions on commercial off- the-shelf (COTS) hardware. To substantiate its roll out, a number of issues (e.g., COTS’ inherent performance and energy efficiency, virtualization overhead, etc.) must be addressed, in a scalable and sustainable manner. Numerous works in the scientific literature manifest the strong correlation of network key performance indicators (KPIs) with the burstiness of the traffic. This paper proposes a novel model-based analytics approach for profiling virtualized network function (VNF) workloads, towards real-time estimation of network KPIs (specifically, power and latency), based on an M X /G/1/SET queueing model that captures both the workload burstiness and system setup times (caused by interrupt coalescing and power management actions). Experimental results show good estimation accuracies for both VNF workload profiling and network KPI estimation, with respect to the input traffic and actual measurements, respectively. This demonstrates that the proposed approach can be a powerful tool for scalable and sustainable network/service management and orchestration. Index Terms—NFV, M X /G/1/SET queue, Real-time analytics, Workload profiling, Power estimation, Latency estimation I. I NTRODUCTION F EW years back, network softwarization has been deemed fundamental towards sustaining the fifth generation mobile radio network (5G) vision. By integrating networking paradigms with state-of-the-art Information Technology (IT) services (i.e., virtualization on top of commercial off-the-shelf (COTS) hardware), it strives to overcome infrastructure ossification. Network Functions Virtualization (NFV) – an emerging softwarization solution – explores the software implementation of network functionalities that would run on COTS hardware [1]. Such a paradigm grants customization and portability to virtualized network functions (VNFs) that would accelerate service innovation and facilitate seamless service support, while minimizing capital expenditures (CAPEX). Despite the numerous gains attainable with NFV, some operational issues that stem from the underlying COTS hardware and virtualization approach adopted need to be handled effectively and efficiently; otherwise, the operational expenditures (OPEX) that result in meeting future demands will prove to become unsustainable. R. Bolla, R. Bruschi, F. Davoli and J. F. Pajo are with the Department of Electrical, Electronic and Telecommunications Engineering, and Naval Architecture (DITEN) of the University of Genoa, and with the National Laboratory of Smart and Secure Networks (S2N) of the Italian National Consortium for Telecommunications (CNIT) (e-mail: raffaele.bolla@unige.it, roberto.bruschi@unige.it, franco.davoli@unige.it, jane.pajo@tnt-lab.unige.it). Contrary to the special-purpose hardware mostly deployed within classical network infrastructures, lower performance and energy efficiency are intrinsic to COTS hardware. While the Advanced Configuration and Power Interface (ACPI) specification [2] equips most – if not all – of it with power management mechanisms (e.g., Low Power Idle (LPI) and Adaptive Rate (AR)), power savings come in trade-off with performance degradation [3]. Moreover, virtualization typically adds extra layer(s) in the networking stack that result in additional processing delays, further lowering the perfor- mance. For a given amount of workload, VNFs may consume even more energy than their physical counterparts [4]. Furthermore, given the highly modular and customizable nature of the virtualized network architecture, coping with the ensuing management complexity entails automated configuration, provisioning and anomaly detection. The ETSI NFV Management and Orchestration (NFV-MANO) framework [5] designates these responsibilities to the virtual infrastructure manager (VIM) of the NFV infrastructure (NFVI). The VIM seeks to obtain performance and anomaly information about virtualized resources based on capacity/usage reports and event notifications, and then to manage them accordingly – yet usually, measurable data do not directly expose network key performance indicators (KPIs). Starting from available and easily measurable performance monitor counters (PMCs) in Linux host servers, this paper tries to bridge this gap through a model-based analytics approach for real-time VNF workload profiling and network KPI (i.e., power and latency) estimation. Specifically, the contribution of this work is two-fold: • a complete analytical characterization of the power- and performance-aware virtualized system, taking into account the inherent workload burstiness, and; • a novel model-based analytics approach for profiling VNF workloads, towards the real-time estimation of the ensuing power consumption and system latency. An initial version of this work has been presented in [6], in which various PMCs are evaluated for the black-box estimation of key statistical features of the VNF workload, considering a fairly general renewal model (M X /G/1/SET queue [7]) that captures traffic burstiness and system setup times. In this extended version, we provide a complete analytical characterization of the M X /G/1/SET queue, which includes power and latency models. This not only augments the capabilities of the VIM, but is also suitable for state-of- the-art dynamic resource and service provisioning approaches. Moreover, we present a new and more thorough experimental