Distributed Controller Placement in Software-Defined Networks with Consistency and Interoperability Problems

Table 3

Distributed control plane summary table.

Ref	Design		Controllers instance	Consistency algorithm	Strength	Weakness	Challenges
	LC	LD					Consistency	Heterogeneity	CPP
ONOS [45]		√	Floodlight	Raft and cassandra	SBi and NBi use TLS and HTTS. It includes IDS and library access authorization	—	Weak	Y	Y
ONIX [44]	√		ONIX	Paxos	Adaptable to network changes and good for high-availability networks	Insufficient protection of privacy and confidentiality	Strong	Y	Y
ODL [46]	√		OpenDayligh	Akka and raft	Arguably the most secured		Strong	Y	Y
DISCO [47]		√	Floodlight	Interdomain agents	Suitable for the heterogeneous network under different administrative control like the Internet	Scalability and reliability persist. It is also insecure	Strong	Y	Y
Ravana [48]	√		RYU	Two-phase replication protocol	Maintain DP and CP consistency	Vulnerable to spoofing, tempering, DoS, and repudiation attacks	Strong	Y	Y
IRIS-HiSA [50]			N/A	Hazelcast	—	—	NA	Y	Y
Hydra [51]		√	Floodlight	Paxos	Differential QoS provisioning	High comm latency between different applications	NA	Y	Y
Elasticon [52]			N/A	Hazelcast	Good load-balancing strategy	Switch migration overhead. It also lacks security measures	Strong	Y	Y
[53]			ODL	Fast paxos			Strong	Y	Y