  Being a state-of-the-art network, Software Defined Networking (SDN) decouples
control and management planes from data plane of the forwarding devices by
implementing both the control and management planes at logically centralized
entity, called controller. This helps to make simple and easy both the network
control and management. Failure of links occurs frequently in a computer
network. To deal with the link failures, the existing approaches computes and
installs multiple paths for a flow at the switches in SDN without considering
the reliability value of the primary path. This incurs extra computation to
compute multiple paths, and both increased computation time and traffic to
install extra flow rules in the network. In this research work we propose a new
approach that calculates the link reliability and then installs the number of
multiple paths based on the reliability value of the primary path. More
specifically, if a primary path has higher reliability then a smaller number of
alternative paths should be installed. This shall decrease the path
computational time and flow rule installation load at controller. Resultantly
there shall be less flow rule entries in switch flow table which in turn will
avoid the overflow of the flow table. Through simulation results, our proposed
approach performs better as compared to the existing approach in term of
computational overhead at controller, end-to-end delay for packet deliver and
the traffic overhead for flow rule installation.
