GD-Aggregate: A WAN Virtual Topology Building Tool for Hard Real-Time and Embedded Applications

The convergence of computer and physical world calls for next generation Wide Area Network (WAN) infrastructures for hard real-time and embedded applications. Such networks need virtual topologies to achieve scalability, configurability, and flexibility. Virtual topologies are made of virtual links, for which, the state-of-the-art building tool is Guaranteed Rate server based aggregates (GR- aggregates). However, common-practice weight assignment scheme couples GR-aggregate End-to-End (E2E) delay bound with aggregate's data throughput inverse proportionally. This is undesirable for many hard real-time embedded sensing/actuating applications, whose traffic has small data throughput but requires short E2E delay. We propose Guaranteed Delay server based aggregates (GD-aggregates), which allow assigning weights according to priorities instead of data throughput. This decouples E2E delay guarantee from data throughput, hence meets the needs of hard realtime embedded applications. In addition, GD-aggregates can be analyzed with simple closed form formulae, and can be easily planned with optimization tools.