Design of light-tree based optical inter-datacenter networks

Nowadays, people´s daily lives are increasingly dependent on Internet applications provided by cloud service providers that replicate their content among geographically distributed datacenters using inter-datacenter wide area networks to meet performance and reliability requirements. This paper provides means for efficient design of inter-datacenter networks with static traffic scenarios, where unicast and multicast connection requests are known a priori along with their start and end times. Also, the optical channel setup/teardown time is given. Integer linear programming (ILP) formulations that consider light-tree and lightpath connections are developed to minimize the network resource consumption. Since solving ILP formulations is time consuming for large networks, we also propose efficient heuristic algorithms. We demonstrate by simulations an advantage in efficiency for a light-tree based heuristic algorithm over its lightpath counterpart. This is due to its ability to construct and extend light-trees to groom more connections. Both heuristic algorithms perform very close to the corresponding ILP optimal results in the case of a small network.