In the context of Network Function Virtualization (NFV), a Network Service (NS) is defined as a composition of Network Functions (NFs), which can be Virtual Network Functions (VNFs) or Physical Network Functions (PNFs). The availability of an NS is among its important characteristics. Moreover, when there is a service outage there is often a service disruption. We define the Service Disruption Time for an NS functionality as the amount of time for which the service state is lost due to service outages for a given period. The Service Data Disruption for an NS functionality is defined as the maximum amount of data lost due to a service outage. To have a comprehensive design solution considering service availability and service disruption, we propose a novel method which enhances an NS design by mapping service-level availability and disruption requirements to constraints on low-level configuration parameters, and calculates the number of required standby instances for each VNF so that the requirements can be met. Our method guarantees the availability and disruption requirements at any scaling level of the NS while minimizing the resource cost. To reduce the complexity of the complete search for the optimal configuration we also propose a heuristic algorithm and perform experiments to compare it with the complete search.

在网络功能虚拟化 (NFV) 的背景下，网络服务 (NS) 被定义为网络功能 (NF) 的组合，可以是虚拟网络功能 (VNF) 或物理网络功能 (PNF)。NS 的可用性是其重要特征之一。此外，当出现服务中断时，通常会出现服务中断。我们将 NS 功能的服务中断时间定义为在给定时间段内由于服务中断而导致服务状态丢失的时间量。NS 功能的服务数据中断定义为由于服务中断而丢失的最大数据量。考虑服务可用性和服务中断的综合设计解决方案，我们提出了一种新方法，该方法通过将服务级别可用性和中断要求映射到低级别配置参数的约束来增强 NS 设计，并计算每个 VNF 所需的备用实例数量，以便满足要求。我们的方法保证了 NS 任何扩展级别的可用性和中断要求，同时最大限度地减少资源成本。为了降低优化配置的完整搜索的复杂度，我们还提出了一种启发式算法并进行了实验以将其与完整搜索进行比较。我们的方法保证了 NS 任何扩展级别的可用性和中断要求，同时最大限度地减少资源成本。为了降低优化配置的完整搜索的复杂度，我们还提出了一种启发式算法并进行了实验以将其与完整搜索进行比较。我们的方法保证了 NS 任何扩展级别的可用性和中断要求，同时最大限度地减少资源成本。为了降低优化配置的完整搜索的复杂度，我们还提出了一种启发式算法并进行了实验以将其与完整搜索进行比较。