Routing multiple services in Optical Transport Network environment using mixed line rates

International Telecommunication Union (ITU-T) has laid down broad principles for the convergence of packet and optical platforms through a series of Optical Transport Network (OTN) protocols. Convergence of multiple services in order to use a common transport layer has emerged as an attractive solution to bring down the capital expenditure and operational costs. In this paper an Integer Linear Programming (ILP) model based on OTN protocol is presented to provide end to end converged optical transport network while dealing with Synchronous Digital Hierarchy (SDH) network, 10 Gigabit Ethernet (10GE), 40 Gigabit Ethernet (40GE) and 100 Gigabit Ethernet (100GE) traffic at the same time. Objective function is defined in terms of the cost of the links on which the traffic was routed, and further these links support mixed line rates. The algorithm has also been studied for evaluating the effect of data grooming and inverse multiplexing at a node. The port size of packet optical transport platform used at each node is approximated in terms of the optimal amount of each type of traffic moving through a node. To reduce the running times, the ILP model has also been evaluated for a greedy routine, what we call Highest Rate First (HRF) ordering, through which the ILP took considerably less time to converge.