A Comparative Study of Cost Effective Multiplexing Approaches for Online Permutation Embedding and Scheduling in Optical Networks

In this paper, we describe a framework for exploring various multiplexing approaches in optical networks and for evaluating their cost-effectiveness. A comparative study of two representative approaches, known as path multiplexing (PM) and link multiplexing (LM) [1, 2], is conducted with respect to online permutation embedding and scheduling. It is found that in many networks, PM can be nearly as effective as LM in that they require (1) about the same multiplexing degree (e.g., the number of wavelengths or time slots) to make a network wide-sense nonblocking and (2) about the same number of rounds on average to schedule a permutation in a blocking network. It is also found that the performance advantage of LM over PM is more obvious in the online case than in the offline case [2]. In addition, such an advantage is proportional to the average connection distance in a network and may be maximized or minimized at some multiplexing degrees. Finally, in either LM or PM, the average schedule length of a permutation is almost the same when the values of the multiplexing degree fall into certain ranges, suggesting that the lowest multiplexing degree within such a range may be used for improved cost-effectiveness.