Profile-based Resource Allocation for Virtualized Network Functions

Accepted in IEEE TNSM Journalhttps://ieeexplore.ieee.org/document/8848599International audienceThe virtualization of compute and network resources enables an unseen flexibility for deploying network services. A wide spectrum of emerging technologies allows an ever-growing range of orchestration possibilities in cloud-based environments. But in this context it remains challenging to rhyme dynamic cloud configurations with deterministic performance. The service operator must somehow map the performance specification in the Service Level Agreement (SLA) to an adequate resource allocation in the virtualized infrastructure. We propose the use of a VNF profile to alleviate this process. This is illustrated by profiling the performance of four example network functions (a virtual router, switch, firewall and cache server) under varying workloads and resource configurations. We then compare several methods to derive a model from the profiled datasets. We select the most accurate method to further train a model which predicts the services' performance, in function of incoming workload and allocated resources. Our presented method can offer the service operator a recommended resource allocation for the targeted service, in function of the targeted performance and maximum workload specified in the SLA. This helps to deploy the softwarized service with an optimal amount of resources to meet the SLA requirements, thereby avoiding unnecessary scaling steps

Discrete-Time Modeling of NFV Accelerators that Exploit Batched Processing

Network Functions Virtualization (NFV) is among the latest network revolutions, promising increased flexibility and avoiding network ossification. At the same time, all-software NFV implementations on commodity hardware raise performance issues when comparing to ASIC solutions. To address these issues, numerous software acceleration frameworks for packet processing have been proposed in the last few years. One central mechanism of many of these frameworks is the use of batching techniques, where packets are processed in groups as opposed to individually. This is required to provide high-speed capabilities by minimizing framework overhead, reducing interrupt pressure, and leveraging instruction-level cache hits. Several such system implementations have been proposed and experimentally benchmarked in the past. However, the scientific community has so far only to a limited extent attempted to model the system dynamics of modern NFV routers exploiting batching acceleration. In this article, we propose a simple, generic model for this type of batching-based systems that can be applied to predict all relevant key performance indicators. In particular, we extend our previous work and formulate the calculation of the queue size as well as waiting time distributions in addition to the batch size distribution and the packet loss probability. Furthermore, we introduce the waiting time distribution as a relevant QoS parameter and perform an in-depth parameter study, widening the set of investigated variables as well as the range of values. Finally, we contrast the model prediction with experimental results gathered in a high-speed testbed including an NFV router, showing that the model not only correctly captures system performance under simple conditions, but also in more realistic scenarios in which traffic is processed by a mixture of functions

Discrete-Time Modeling of NFV Accelerators that Exploit Batched Processing

Network Functions Virtualization (NFV) is among the latest network revolutions, bringing flexibility and avoiding network ossification. At the same time, all-software NFV implementations on commodity hardware raise performance issues with respect to ASIC solutions. To address these issues, numerous software acceleration frameworks for packet processing have appeared in the last few years. Common among these frameworks is the use of batching techniques. In this context, packets are processed in groups as opposed to individually, which is required at high-speed to minimize the framework overhead, reduce interrupt pressure, and leverage instruction-level cache hits. Whereas several system implementations have been proposed and experimentally benchmarked, the scientific community has so far only to a limited extent attempted to model the system dynamics of modern NFV routers exploiting batching acceleration. In this paper, we fill this gap by proposing a simple generic model for such batching-based mechanisms, which allows a very detailed prediction of highly relevant performance indicators. These include the distribution of the processed batch size as well as queue size, which can be used to identify loss-less operational regimes or quantify the packet loss probability in high-load scenarios. We contrast the model prediction with experimental results gathered in a high-speed testbed including an NFV router, showing that the model not only correctly captures system performance under simple conditions, but also in more realistic scenarios in which traffic is processed by a mixture of functions