P4-Based In-Network Telemetry for FPGAs in the Open Cloud Testbed and FABRIC

In recent years, Field Programmable Gate Arrays (FPGAs) have gained prominence in cloud computing data centers, driven by their capacity to offload compute-intensive tasks and contribute to the ongoing trend of data center disaggregation, as well as their ability to be directly connected to the network. While FPGAs offer numerous advantages, they also pose challenges in terms of configuration, programmability, and monitoring, particularly in the absence of an operating system with essential features like the TCP/IP networking stack. This paper introduces an In-band Network Telemetry (INT) approach based on the P4 language for FPGA data plane programming. The goal is to facilitate monitoring and network performance analysis by providing one-way packet delay information. The approach is demonstrated in the Open Cloud Testbed (OCT) and FABRIC testbeds, both offering open access to the research community with greater FPGA availability than commercial clouds. The workflow enables researchers to create custom P4 programs and bitstreams for installation on FPGAs. The paper presents a multi-step approach allowing experimentation within the New England Research Cloud (NERC), testing in OCT, and final deployment in FABRIC, well-suited for one-way delay measurements due to synchronized clocks via GPS time signals. Contributions include the provision of a P4 workflow for FPGAs in a research cloud, a novel FPGA clock-based INT approach, and a comprehensive evaluation through simulation and experiments in the Open Cloud and FABRIC testbeds.