Abstract

In-network computing is an emerging trend that enables the execution of programs in the data-plane, thanks to the introduction of programmable networked devices.

Although cloud service providers, such as Amazon, Microsoft and Google, are increasingly deploying such programmable hardware in their infrastructures, we still need an infrastructure for verifying deployed programs and for debugging them in real time. Previous approaches for debugging programmable network hardware suffer from a number of limitations: formal verification tools are not able to detect bugs affecting formally correct programs once they are deployed in the network, while external debuggers only allow passive debugging in response to externally generated packets and cannot verify packets at line rate in real time.

To address these challenges, we propose a new debugging infrastructure that leverages recent advances in network programmability and hardware design, by providing unprecedented visibility into the internal state and operations of network devices. Our debugging framework, named P4Debug, includes three major components: (i) an extension to the target architecture to allow for packet generation for active debugging, (ii) a debug module that is parallel to the packet-processing pipeline, and (iii) debug-specific language extensions to P4.