When raft meets SDN: How to elect a leader and reach consensus in an unruly network

Yang Zhang, Eman Ramadan, Hesham Mekky, Zhi-Li Zhang

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

14 Scopus citations

Abstract

In SDN, the logically centralized control plane (“network OS”) is often realized via multiple SDN controllers for scalability and reliability. ONOS is such an example, where it employs Raft – a new consensus protocol developed recently – for state replication and consistency among the distributed SDN controllers. The reliance of network OS on consensus protocols to maintain consistent network state introduces an intricate inter-dependency between the network OS and the network under its control, thereby creating new kinds of fault scenarios or instabilities. In this paper, we use Raft to illustrate the problems that this inter-dependency may introduce in the design of distributed SDN controllers and discuss possible solutions to circumvent these issues.

Original languageEnglish (US)
Title of host publicationAPNET 2017 - Proceedings of the 2017 Asia-Pacific Workshop on Networking
PublisherAssociation for Computing Machinery
Pages1-7
Number of pages7
ISBN (Print)9781450352444
DOIs
StatePublished - Aug 3 2017
Event1st Asia-Pacific Workshop on Networking, APNET 2017 - Hong Kong, China
Duration: Aug 3 2017Aug 4 2017

Publication series

NameACM International Conference Proceeding Series

Other

Other1st Asia-Pacific Workshop on Networking, APNET 2017
Country/TerritoryChina
CityHong Kong
Period8/3/178/4/17

Bibliographical note

Funding Information:
SDN controllers use distributed consensus protocols, like Raft, to manage the network state and provide a highly available cluster to the underlying networking elements. Therefore, SDN controller liveness depends on all-to-all message delivery between cluster servers. In this paper, we use Raft to illustrate the problems which may be induced by this interdependency in the design of distributed SDN controllers. We also discuss possible solutions to circumvent these issues. Our preliminary results show the effectiveness of PrOG in improving the availability of leadership in Raft used by critical applications like SDN controller clusters. Acknowledgement. This research was supported in part by DTRA grant HDTRA1-14-1-0040, DoD ARO MURI Award W911NF-12-1-0385 and NSF grants CNS-1618339, CNS-1618339 and CNS-1617729.

Keywords

  • Consensus
  • Raft algorithm
  • Resilient Routing
  • SDN

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