Tracking P4 program execution in the data plane

Suriya Kodeswaran, Mina Tahmasbi Arashloo, Praveen Tammana, Jennifer Rexford

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

While programmable switches provide operators with much-needed control over the network, they also increase the potential sources of packet-processing errors. Bugs can happen anywhere: in the P4 program, the controller installing rules into tables, or the compiler that maps the P4 program into the resource-constrained switch pipelines. Most of these bugs manifest themselves after certain sequences of packets with certain combinations of rules in the tables. Tracking each packet's execution path through the P4 program, i.e., the sequence of tables hit and the actions applied, directly in the data plane is useful in localizing such bugs as they occur in real time. The fact that programmable data planes require P4 programs to be loop-free and can perform simple integer arithmetic operations makes them amenable to Ball-Larus encoding, a well-known technique in profiling execution paths in software programs that can efficiently encode all N paths in a single [log(N)]-bit variable. However, for real-world P4 programs, the path variable can get quite large, making it inefficient for integer arithmetic at line rate. Moreover, the encoding could require a subset of tables, that would otherwise have no data dependency, to update the same variable. By carefully breaking up the P4 program into disjoint partitions and tracking each partition's execution path separately, we show how to minimally augment P4 programs to track the execution path of each packet.

Original languageEnglish (US)
Title of host publicationSOSR 2020 - Proceedings of the 2020 Symposium on SDN Research
PublisherAssociation for Computing Machinery, Inc
Pages117-122
Number of pages6
ISBN (Electronic)9781450371018
DOIs
StatePublished - Mar 3 2020
Event2020 Symposium on SDN Research, SOSR 2020 - San Jose, United States
Duration: Mar 3 2020 → …

Publication series

NameSOSR 2020 - Proceedings of the 2020 Symposium on SDN Research

Conference

Conference2020 Symposium on SDN Research, SOSR 2020
CountryUnited States
CitySan Jose
Period3/3/20 → …

All Science Journal Classification (ASJC) codes

  • Computer Networks and Communications
  • Software

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  • Cite this

    Kodeswaran, S., Arashloo, M. T., Tammana, P., & Rexford, J. (2020). Tracking P4 program execution in the data plane. In SOSR 2020 - Proceedings of the 2020 Symposium on SDN Research (pp. 117-122). (SOSR 2020 - Proceedings of the 2020 Symposium on SDN Research). Association for Computing Machinery, Inc. https://doi.org/10.1145/3373360.3380843