Optimal placement of Controllers for the Adoption of Software Defined Networking: In the case of ethiotelecom
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Date
2018-11-14
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AAU
Abstract
The tremendous increase of data traffic has been a key reason for the upgrading
of traditional networks. One of the new models that has been developed for redesigning
and managing communication networks is software-defined networking
(SDN). The main idea behind SDN is the decoupling of the control and data planes,
which enables the centralization of the control plane and the programmability of
the data plane. The decoupling of control and data planes in SDN brings benefits
in terms of logically centralized control and application programming. But, the
single point of management in physically centralized SDN architectures is a potential
point of failure and a bottleneck that compromises network reliability and
performance.
To avoid such concerns, SDN control architectures are usually designed as physically
distributed systems. This raises practical challenges about the best approach
to decentralize the control plane while maintaining the logically centralized network
view. In particular, determining the number of controllers and locating them
in a wide area network (WAN) is a challenging task that should be addressed appropriately.
The work presented in this thesis addresses the above challenges through clustering
and heuristic based optimization models. ethiotelecom WAN was considered
as a case study; the network topology is encoded, examined, and the selected algorithms
for determining the minimum number of controllers and their optimal
location in the WAN, were applied with the goal of enhancing and minimizing
global latency and considering the node to controller assignment imbalance.
The optimization is done in two scenarios, controller placement using K Medoid
method and Pareto simulated annealing (PSA) method. First, the controllers placement
of K-Medoid and Pareto simulated annealing algorithm for different numbers
of controllers K is found and investigated. Followed by, a comparison of the
results found using k-Medoids clustering model with the Pareto simulated annealing
heuristic model is conducted. From the results it is found that the minimum
number of controllers required to adopt SDN in ethiotelecom WAN is eight
controllers and the k medoid clustering based model is better than the Pareto
simulated annealing method in the optimal placement of controllers in the WAN
topology for larger number of network elements (Nodes).
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Keywords
Software-Defined Networking (SDN), OpenFlow, Wide Area Networks (WAN), Controller placement, Optimization, Clustering, Control plane, Data plane