Dynamic scheduling of optical data bursts in time-domain wavelength interleaved networks

We consider the problem of scheduling bursts of data in an optical network with an ultra-fast tunable laser and a fixed receiver at each node. In (K. Ross et al, Technical Report SU NETLAB-2002-12/1, Eng. Lib., Stanford Uni., Stanford, CA (2002)) we considered the static scheduling problem of meeting demand in the minimal time. Here we substantially extend these results to the case of online, dynamic scheduling. Due to the high data rates employed on the optical links, the burst transmissions typically last for very short times compared to the round trip propagation times between source-destination pairs. A good schedule ensures that (i) there are no transmit/receive conflicts, (ii) throughput is maximized, and (iii) propagation delays are observed. We formulate the scheduling problem as a generalization of the well-known crossbar switch scheduling problem. We show that the algorithms presented in the previous work can be implemented in dynamic form to give 100% throughput. Further, we show that one of the more intuitive solutions does not lead to maximal throughput. In particular, we show advantages of adaptive batch sizes rather than fixed batch sizes for both throughput and performance.