Using trio: juniper networks' programmable chipset - for emerging in-network applications

This paper describes Trio, a programmable chipset used in Juniper Networks' MX-series routers and switches. Trio's architecture is based on a multi-threaded programmable packet processing engine and a hierarchy of high-capacity memory systems, making it fundamentally different from pipeline-based architectures. Trio gracefully handles non-homogeneous packet processing rates for a wide range of networking use cases and protocols, making it an ideal platform for emerging in-network applications. We begin by describing the Trio chipset's fundamental building blocks, including its multi-threaded Packet Forwarding and Packet Processing Engines. We then discuss Trio's programming language, called Microcode. To showcase Trio's flexible Microcode-based programming environment, we describe two use cases. First, we demonstrate Trio's ability to perform in-network aggregation for distributed machine learning. Second, we propose and design an in-network straggler mitigation technique using Trio's timer threads. We prototype both use cases on a testbed using three real DNN models (ResNet50, DenseNet161, and VGG11) to demonstrate Trio's ability to mitigate stragglers while performing in-network aggregation. Our evaluations show that when stragglers occur in the cluster, Trio outperforms today's pipeline-based solutions by up to 1.8x.