This special issue introduces original results and achievements by researchers working on different issues and challenges related to network and service management. For this special issue, the best papers of the 23rd edition of the Brazilian Workshop on Network and Service Management (WGRS 2018) were invited to submit an extended version of the conference paper. In total, three articles were accepted from three different areas, including mobility management, video distribution, software-defined networking (SDN), distributed applications, and network functions virtualization (NFV).

In the first contribution entitled “SDN-based architecture for providing quality of service to high-performance distributed applications,” Oliveira et al. introduce a quality of service (QoS) provisioning architecture where network operators could specify QoS level in a simple way. Their proposed architecture uses the benefits of SDN's flexibility and effective network management in high-performance distributed systems. The authors manipulated the packet headers' fields and used the OpenFlow protocol to enable their proposed architecture to be application-aware, instead of other costly approaches (e.g., deep packet inspection or machine learning), and to allow QoS specification for each individual data flow on the network. The authors presented three proof-of-concept experiments results and concluded that a proper parameter of classes of service reduced the transfer time and conserved the bandwidth for sensitive flows.

In the subsequent contribution entitled “Beyond VNFM: Filling the gaps of the ETSI VNF manager to fully support VNF life cycle operations,” Venâncio et al. propose a virtualized network functions manager (VNFM) to support distinct platforms and VNF use case scenarios. Their proposed VNFM brings simplifications that the authors judge as a fundamental set of operations to fully manage the VNF life cycle, thus specifying a set of application programming interface (APIs), components, and modules, for the end user and back-end. The authors evaluated their proposal at both hardware and software levels through a prototype implementation of VNFM performing certain tasks (i.e., instantiation, deletion, and update of the VNFs). They concluded that their proposed solution could complement the European Telecommunications Standards Institute (ETSI) standard NFV architectural framework by abstracting several management procedures.

In the third paper entitled “Quality of experience and quality of service-aware handover for video transmission in heterogeneous networks,” Medeiros et al. present a QoS, quality of experience (QoE), and radio-aware handover management algorithm in heterogeneous networks to deliver video with QoS/QoE support over a heterogeneous networks. The authors considered the analytic hierarchy process (AHP) as a multiple-criteria decision-making tool to evaluate the most appropriate base station for the mobile nodes to connect in real time. Their study highlighted the importance of using distinct QoS, QoE, and radio parameters, namely, reference signal received quality (RSRQ), packet delivery ratio (PDR), and predictive mean opinion score (pMOS), in the handover decision, since the current algorithms do not consider many variables and are not enough to provide efficient handover decision-making for video transmission.

The guest editors would like to thank the Editor-in-Chief of the International Journal on Network Management for providing the opportunity to publish this special issue. We would also like to thank the reviewers for spending their precious time in evaluating the submitted papers. Finally, we hope that the readers enjoy the papers from this special issue.

DATA AVAILABILITY STATEMENT

There is no data available for the manuscript.

中文翻译：

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巴西网络和服务管理研讨会 (WGRS) 第 23 版精选论文特刊编辑

本期特刊介绍了研究与网络和服务管理相关的不同问题和挑战的研究人员的原创成果和成就。本期特刊邀请了第 23 届巴西网络和服务管理研讨会 (WGRS 2018) 的最佳论文提交会议论文的扩展版。总共收到来自三个不同领域的三篇文章，包括移动管理、视频分发、软件定义网络（SDN）、分布式应用程序和网络功能虚拟化（NFV）。

在题为“为高性能分布式应用程序提供服务质量的基于 SDN 的架构”的第一个贡献中，Oliveira 等人。引入服务质量 (QoS) 供应架构，网络运营商可以在其中以简单的方式指定 QoS 级别。他们提出的架构利用了 SDN 在高性能分布式系统中的灵活性和有效网络管理的优势。作者操纵数据包标头的字段并使用 OpenFlow 协议使他们提出的架构能够感知应用程序，而不是其他昂贵的方法（例如，深度数据包检查或机器学习），并允许对每个单独的数据流进行 QoS 规范在网络上。

在随后的题为“超越 VNFM：填补 ETSI VNF 管理器的空白以完全支持 VNF 生命周期操作”的文章中，Venâncio 等人。提出一个虚拟化网络功能管理器 (VNFM) 来支持不同的平台和 VNF 用例场景。他们提出的 VNFM 带来了简化，作者将其视为完全管理 VNF 生命周期的基本操作集，从而为最终用户和后端指定了一组应用程序编程接口 (API)、组件和模块。作者通过执行某些任务（即 VNF 的实例化、删除和更新）的 VNFM 原型实现，在硬件和软件级别评估了他们的提议。

在题为“异构网络中视频传输的体验质量和服务感知切换质量”的第三篇论文中，Medeiros 等人。在异构网络中提供 QoS、体验质量 (QoE) 和无线电感知切换管理算法，以通过异构网络提供具有 QoS/QoE 支持的视频。作者将层次分析法 (AHP) 视为一种多标准决策工具，以评估最适合移动节点实时连接的基站。他们的研究强调了在切换决策中使用不同的 QoS、QoE 和无线电参数的重要性，即参考信号接收质量 (RSRQ)、数据包传输率 (PDR) 和预测平均意见得分 (pMOS)，

客座编辑要感谢International Journal on Network Management的主编提供出版本期特刊的机会。我们还要感谢审稿人花费宝贵的时间来评估提交的论文。最后，我们希望读者喜欢本期特刊的论文。

数据可用性声明

手稿没有可用的数据。