In the ongoing process of telecommunications systems softwarization, a key role is played by Virtual Network Functions deployed in Cloud environments and interconnected through Software Defined Networks. The separation between data, control and service logic changes the way in which those systems are designed, operated, and capitalized, and also enables elasticity, flexibility and cost-efficiency in the whole ICT ecosystem. However, dedicated and reliable monitoring tools are required to take full advantage of software-based telecommunication systems. Such tools are expected to effectively combine metrics about various assets to provide a global view over the infrastructure, offload control plane from monitoring tasks to improve scalability, and be seamlessly integrated with the existing control plane through the interface. In this paper, we propose a monitoring module that meets the requirements imposed by the softwarization process. We present the reference architecture for the proposed solution, along with the fundamental assumptions we have based our work upon, and a Proof-of-Concept implementation. Our solution has been designed as a standalone Virtual Network Function, fully decoupled from the existing control plane. As a result, new features and degrees of freedom are available, especially in terms of adaptability to the heterogeneous softwarized infrastructure, with no modifications needed in the existing software or hardware components. The proposed modular architecture, supported by proper interfaces, can be integrated with a variety of tools to collects statistics from different assets, relieving the control plane from the burden of computational-intensive monitoring tasks.

In order to carefully validate the design of the proposed unified and standalone monitoring module numerous scenarios addressing various aspects and potential impediments were considered, in a series of experiments run on our internal testbeds and on an auxiliary public cloud environment. The obtained results prove that our monitoring tool provides significant advantages with respect to the existing solutions which are integrated in the control plane. Therefore, it is able to cooperate with sophisticated traffic steering and cloud management mechanisms operating on the combined network and computing resources. Furthermore, we demonstrate that our solution is easily portable, for instance to a public cloud environment.

在正在进行的电信系统软化进程中，由部署在云环境中并通过软件定义网络互连的虚拟网络功能扮演着关键角色。数据，控制和服务逻辑之间的分离改变了这些系统的设计，操作和资本化方式，并且还实现了整个ICT生态系统的弹性，灵活性和成本效益。但是，需要专用且可靠的监视工具才能充分利用基于软件的电信系统。预计此类工具将有效地组合有关各种资产的指标，以提供基础结构的全局视图，将控制平面从监视任务中卸载下来以改善可伸缩性，并通过该接口与现有控制平面无缝集成。在本文中，我们提出了一个监控模块，该模块可以满足软化过程。我们提供了所提出的解决方案的参考架构，以及我们基于其工作所做的基本假设以及概念验证的实现。我们的解决方案被设计为独立的虚拟网络功能，与现有的控制平面完全分离。结果，可获得新的功能和自由度，特别是在对异构软化基础架构的适应性方面，而无需对现有软件或硬件组件进行任何修改。所提议的模块化体系结构由适当的接口支持，可以与各种工具集成，以收集来自不同资产的统计信息，从而减轻了控制平面的计算量大的监视任务的负担。

为了仔细验证提议的统一和独立监控模块的设计，在我们内部测试平台和辅助公共云环境上进行的一系列实验中，考虑了解决各个方面和潜在障碍的众多方案。获得的结果证明，相对于集成在控制平面中的现有解决方案，我们的监控工具具有明显的优势。因此，它能够与在组合的网络和计算资源上运行的复杂流量控制和云管理机制配合。此外，我们证明了我们的解决方案易于移植，例如到公共云环境中。