A robust‐link controller placement model for large‐scale software defined networks

Abstract

The software defined network (SDN) is a novel flexible network architecture. For the purpose of facilitating management, multiple controllers need to be placed in large‐scale SDN. When a link failure occurs, the path can be re‐planned by the control layer. However, unreasonable controller placement scheme brings about a sharp latency increase between controllers and switches. The reliability of the SDN is therefore affected. To this end, we define a link robust distance (LRD) by considering the states during link failures and non‐link failures. Then, we use it design a robust link controller placement model (RLCPM) which can reduce the impact of link failures on the delay between the controller and the switch. In addition, we design a heuristic algorithm with low‐time complexity to solve the RLCPM more effectively. Experimental results show that, compared with other models, RLCPM simplifies the controller placement problem when considering a link failure. The maximum latency between controllers and switches of the obtained controller placement scheme is lower.

A Multi-Controller Placement Strategy for Hierarchical Management of Software-Defined Networking

“…Ahmadi et al [15] used an adaptive heuristic algorithm to solve for switch-to-controller latency, inter-controller latency and load as three optimization metrics. Wang et al [16] designed a robust link controller placement model and a heuristic algorithm with lower time complexity to solve the CPP problem more efficiently. Firouz et al [17] used a hybrid discrete multi-objective algorithm to solve the three metrics' optimization of switch-tocontroller latency, inter-controller latency and load.…”

“…P c loc c ove = max ∑ g∈C loc ,q∈C ove P(g, q), P(g, q) = ∏ l∈E p l (16) where p l is the probability of failure of the link(v i ,v j ), this paper uses a random number between 0.01 and 0.1, which can also be replaced by collecting the actual probability of link failure. P(i, j) is the probability of failure between node i and node j, P c loc s is the sum of the maximum likelihood of link failure between all local controllers C loc , and all switches S in the control domain to which they belong, and P c loc c ove is the maximum probability of link failure between all local controllers C loc to the global controller C ove .…”