Multicast allows sending a message to multiple recipients without having to create and send a separate message for each recipient. This preserves network bandwidth, which is particularly important in time-sensitive networks. These networks are commonly used to provide latency-bounded communication for real-time systems in domains like automotive, avionics, industrial internet of things, automated shop floors, and smart energy grids. The preserved bandwidth can be used to admit additional real-time messages with specific quality of service requirements or to reduce the end-to-end latencies for messages of any type. However, using multicast communication can complicate traffic planning, as it requires free queues or available downstream egress ports on all branches of the multicast tree. In this work, we present a novel multicast partitioning technique to split multicast trees into smaller multicast or unicast trees. This allows for a more fine-grained trade-off between bandwidth utilization and traffic scheduling difficulty. Thus, schedulability in dynamic systems can be improved, in terms the number of admitted streams and the accumulated network throughput. We evaluated the multicast partitioning on different network topologies and with three different scheduling algorithms. With the partitioning, 5-15\% fewer streams were rejected, while achieving 5-125\% more network throughput, depending on the scheduling algorithm.

翻译：多播允许将消息发送给多个接收者，而无需为每个接收者单独创建和发送消息。这节省了网络带宽，在时间敏感网络中尤为重要。此类网络通常用于为汽车、航空电子、工业物联网、自动化车间和智能电网等领域的实时系统提供时延有界通信。节省的带宽可用于接纳更多具有特定服务质量要求的实时消息，或降低任意类型消息的端到端时延。然而，使用多播通信可能使流量规划复杂化，因为它要求在多播树的所有分支上均存在空闲队列或可用的下游出口端口。本文提出一种新颖的多播划分技术，将多播树分割为更小的多播树或单播树。该方法能在带宽利用率与流量调度难度之间实现更精细化的权衡，从而在接纳流数量与累积网络吞吐量方面提升动态系统的可调度性。我们在不同网络拓扑结构上使用三种调度算法对多播划分进行了评估。实验表明，根据调度算法的不同，采用划分技术后流拒绝率降低5-15%，同时网络吞吐量提升5-125%。