Study On Traffic Grooming With Mixed Line Rates In OTN Metro Network

With the rapid growth of data services, especially the mobile Internet services, the metrotransport network has more and more demands for high-bit-rate services.The existing MAN, due toits technical limitations, can not meet the demand of service transport in the near future. OTNtechnology, as a new type of optical transmission technology, has both the advantage of WDM andthat of SDH with large-capacity scheduling, operation and management capabilities and flexiblenetworking. It is the network operator’s major choice for optical metro networks.Future telecommunication networks are expected to be flat-structured and support a variety oftraffic demands.The mixed line rates means that different optical channels can have differenttransmission rates in a network.The reuse of line cards and a wide variety of traffic demands are thecause of the presence of mixed line rates in a network. It may be convenient to set up lightpathswith different bit rates(10/40/100Gbps). Then, the network design cost can be reduced becauselow-bit-rate service will need less grooming (less multiplexing with other low-bit-rate service ontothe lowest high-capacity wavelength) while high-bit-rate services can be accommodated on awavelength itself. Because of the mixed line rates’s characteristics, a traffic grooming algorithmwith mixed line rates is presented in metro OTN networks in this paper.First, the paper gives a grooming model and its corresponding ILP algorithms for trafficgrooming problem with mix-line rates in metro optical networks. Its objective is to minimize thetotal cost of all used line cards. Because it is a NP-hard problem, a heuristic algorithm and animproved heuristic algorithm are proposed to solve the grooming problem in medium and largenetworks. The comparison of the two algorithms proved that the improved heuristic algorithm hasbetter performance.Then the improved algorithm is applied to the networks with mesh and ringtopologies, and results of MLR and SLR networks are compared. The simulation results show thatMLR network can reduce the cost of a network.