SDN-enabled Application-aware Network Control Architectures and their Performance Assessment (DFG SDN-App)Phase 2: Design and Evaluation of Flexible Programmable Hybrid Real-time Networks with Hard and Soft Real-time Guarantees

软件定义网络（SDN）标志着一个根本的范式转变，允许在当今的通信网络中集成新概念，如应用感知资源管理。特别地，这样的概念改善了面向用户的多媒体应用的体验质量（QoE）。DFG SDN-App的第一阶段已经证明了这一概念的可行性。第一阶段的架构从两个方面研究了应用感知管理和控制的实现：在应用控制平面上考虑网络信息，提高网络资源的利用率;考虑网络控制平面上的应用需求，严格提高了应用性能和QoE。DFG SDN-因此，应用程序扩展了所考虑的场景和架构：除了照顾面向最终用户的多媒体应用程序和QoE（第1阶段），它新集成了时间关键型（工业）服务及其不断变化的需求-最终用户不起主导作用的情况。特别是，第2阶段侧重于时间关键型服务的硬实时和软实时需求，这些服务具有动态变化的需求，如智能制造控制设备。硬实时约束要求，例如，最大端到延迟和最大延迟抖动;软实时约束体现在随机保证中，例如，数据包丢失和延迟。现有的方法遭受未使用的，因此浪费的网络资源或复杂性，以解决动态变化的需求和网络重新配置。第二阶段的目标是实现一个混合实时网络，该网络通过分析、仿真、测量和测试平台实现，为硬实时和软实时应用提供保证，同时托管多媒体应用。特别是，时间敏感网络（TSN）和网络可编程性（P4）等概念进行了研究和分析。为了评估整体架构，不仅传统的措施，而且新的措施，如网络的灵活性进行了调查，以量化的混合实时网络在不断变化的需求与时间和成本的限制下的好处。总体目标是为选定的用例（工业、数据中心、广域网）提供指导，这些用例将联合收割机第1阶段和第2阶段的结果结合起来。第1阶段向工业和实时网络的扩展对于维持当今应用的动态和快速增长的需求非常重要。一个灵活的架构，提供保证，在面对重新配置将允许实现混合网络，可以托管所有应用类型的同时。通过为各种网络场景编程和使用标准硬件的能力，网络运营商将在未来节省运营和资本支出。

Software Defined Networking (SDN) marks a fundamental paradigm shift that allows integrating new concepts such as application-aware resource management in today’s communication networks. Such concepts, in particular, improve the Quality-of-Experience (QoE) of user-oriented multimedia applications. The feasibility of such concept was demonstrated in Phase 1 of DFG SDN-App. The Phase 1 architecture investigated the realization of application-aware management and control on two fronts: taking network information on the application control plane into account improves the use of network resources; considering application demands on the network control plane rigorously improves application performance and QoE.Phase 2 of DFG SDN-App consequently extends the considered scenario and architecture: besides taking care of end user-oriented multimedia applications and QoE (Phase 1), it newly integrates time-critical (industrial) services and their changing requirements – cases where end users do not play a dominant role. In particular, Phase 2 focuses on hard as well as soft real-time requirements of time-critical services with dynamically changing demands like smart manufacturing to control devices. Hard real-time constraints require, e.g., a maximum end-to-delay and maximum delay jitter; soft real-time constraints manifest in stochastic guarantees, e.g., on packet loss and delay. Existing approaches suffer from unused, hence wasted network resources or the complexity to address dynamically changing demands and network reconfigurations. Real-time constraints are in trade-off to flexibility.Applying the methodologies from analysis, simulation, to measurement and testbed implementations, the goal of Phase 2 is to realize a hybrid real-time network that provides guarantees to hard and soft real-time applications, while at the same time hosting multimedia applications. In particular, concepts such as Time Sensitive Networking (TSN) and network programmability (P4) are investigated and analyzed jointly. To evaluate the overall architecture, not only traditional measures are applied, but also new measures such as network flexibility are investigated to quantify the benefits of hybrid real-time networks under changing demands with time and cost constraints. The overall target are guidelines for selected use cases (industrial, data center, wide area network), that combine the results of Phase 1 and 2.An extension of Phase 1 towards industrial and real-time networks is important to sustain the dynamically and faster growing demands of today’s applications. A flexible architecture that provides guarantees in face of reconfigurations will allow realizing hybrid networks that can host all application types simultaneously. With the ability to program and use standard hardware for all kind of network scenarios, network operators will save operation and capital expenditures in the future.