Hybrid IP networks that use both control paradigms - distributed andcentralized - promise the best of two worlds: programmability and agility ofSDN, and reliability and fault tolerance of distributed routing protocols likeOSPF. The common approaches follow a division of labor concept, where SDNcontrols prioritized traffic and OSPF assures care-free operation of besteffort traffic. We propose SDN Partitioning, which establishes centralizedcontrol over the distributed routing protocol by partitioning the topology intosub-domains with SDN-enabled border nodes, such that OSPF's routing updateshave to traverse SDN border nodes to reach neighboring sub-domains. This allowsthe central controller to modify how sub-domains view one another, which inturn allows to steer inter-sub-domain traffic. The degree of dynamic controlagainst simplicity of OSPF can be trade off by adjusting the size of thesub-domains. This paper explains the technical requirements, presents a novelscheme for balanced topology partitioning, and provides the models for commonnetwork management tasks. Our performance evaluation shows that - already inits minimum configuration with two sub-domains - SDN Partitioning providessignificant improvements in all respects compared to legacy routing protocols,whereas smaller sub-domains provide network control capabilities comparable tofull SDN deployment.
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