RuleScope: Inspecting forwarding faults for software-defined networking

Xitao Wen, Kai Bu*, Bo Yang, Yan Chen, Li Erran Li, Xiaolin Chen, Jianfeng Yang, Xue Leng

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Software-defined networking (SDN) promises unprecedentedly flexible network management but it is susceptible to forwarding faults. Such faults originate from data-plane rules with missing faults and priority faults. Yet existing fault detection ignores priority faults, because they are not discovered on commercial switches until recently. In this paper, we present RuleScope, a more comprehensive solution for inspecting SDN forwarding. RuleScope offers a series of accurate and efficient algorithms for detecting and troubleshooting rule faults. They inspect forwarding behavior using customized probe packets to exercise data-plane rules. The detection algorithm exposes not only missing faults but also priority faults and the troubleshooting algorithm uncover actual forwarding states of data-plane flow tables. Both of them help track real-time forwarding status and benefit reliable network monitoring. Furthermore, toward fast inspection of dynamic networks, we propose incremental algorithms for rapidly evolving network policies to amortize detection and troubleshooting overhead without sacrificing accuracy. Experiments with our prototype on the Ryu SDN controller and Pica8 P-3297 switch show that the RuleScope achieves accurate fault detection on 320-entry flow tables with a cost of 1500+ probe packets within 16 s.

Original languageEnglish (US)
Article number7892027
Pages (from-to)2347-2360
Number of pages14
JournalIEEE/ACM Transactions on Networking
Issue number4
StatePublished - Aug 2017


  • Software-defined networking
  • forwarding fault
  • network troubleshooting

ASJC Scopus subject areas

  • Software
  • Computer Science Applications
  • Computer Networks and Communications
  • Electrical and Electronic Engineering

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