Modern computer networks based on the software-defined networking (SDN) paradigm are becoming increasingly complex and often require frequent configuration changes in order to react to traffic fluctuations. It is essential that forwarding policies are preserved not only before and after the configuration update but also at any moment during the inherently distributed execution of such an update. We present Kaki, a Petri game based tool for automatic synthesis of switch batches which can be updated in parallel without violating a given (regular) forwarding policy like waypointing or service chaining. Kaki guarantees to find the minimum number of concurrent batches and supports both splittable and nonsplittable flow forwarding. In order to achieve optimal performance, we introduce two novel optimisation techniques based on static analysis: decomposition into independent subproblems and identification of switches that can be collectively updated in the same batch. These techniques considerably improve the performance of our tool Kaki, relying on TAPAAL’s verification engine for Petri games as its backend. Experiments on a large benchmark of real networks from the Internet Topology Zoo database demonstrate that Kaki outperforms the state-of-the-art tools Netstack and FLIP. Kaki computes concurrent update synthesis significantly faster than Netstack and compared to FLIP, it provides shorter (and provably optimal) concurrent update sequences at similar runtimes.

基于软件定义网络 (SDN) 范式的现代计算机网络变得越来越复杂，通常需要频繁更改配置才能对流量波动做出反应。重要的是，不仅在配置更新之前和之后保留转发策略，而且在此类更新的固有分布式执行期间的任何时刻都保留转发策略。我们推出了 Kaki，一种基于 Petri 游戏的工具，用于自动合成交换机批次，可以并行更新，而不会违反给定的（常规）转发策略，如路径点或服务链。Kaki 保证找到最小并发批数，并支持可拆分和不可拆分的流转发。为了实现最佳性能，我们引入了两种基于静态分析的新颖优化技术：分解为独立的子问题并识别可以在同一批次中集体更新的开关。这些技术极大地提高了我们工具 Kaki 的性能，它依靠 TAPAAL 的 Petri 游戏验证引擎作为后端。对 Internet Topology Zoo 数据库中的大型真实网络基准进行的实验表明，Kaki 的性能优于最先进的工具 Netstack 和 FLIP。Kaki 计算并发更新综合的速度明显快于 Netstack，并且与 FLIP 相比，它在相似的运行时间下提供了更短（并且可证明是最佳的）并发更新序列。依托TAPAAL的Petri游戏验证引擎作为后端。对 Internet Topology Zoo 数据库中的大型真实网络基准进行的实验表明，Kaki 的性能优于最先进的工具 Netstack 和 FLIP。Kaki 计算并发更新综合的速度明显快于 Netstack，并且与 FLIP 相比，它在相似的运行时间下提供了更短（并且可证明是最佳的）并发更新序列。依托TAPAAL的Petri游戏验证引擎作为后端。对 Internet Topology Zoo 数据库中的大型真实网络基准进行的实验表明，Kaki 的性能优于最先进的工具 Netstack 和 FLIP。Kaki 计算并发更新综合的速度明显快于 Netstack，并且与 FLIP 相比，它在相似的运行时间下提供了更短（并且可证明是最佳的）并发更新序列。