Incremental multi-hop scheduling algorithms for all-optical broadcast-and-select networks with arbitrary tuning latencies

We focus on all-optical broadcast and select slotted WDM networks. Each network user is equipped with one tunable transmitter and one fixed receiver; full connectivity is achieved by tuning transmitters to all different wavelengths available in the optical spectrum. Tuning latencies are considered to be not negligible with respect to the slot time. A centralized network controller allocates slots in a TDM/WDM frame according to requests issued by users. User requests are accommodated in the frame incrementally, as soon as they are received by the network controller. We propose a novel scheduling algorithm that may route some flows from source to destination through some intermediate nodes, following a multi-hop approach. Since we aim at an incremental solution, we impose a transparency constraint: new user requests may be accepted only without affecting existing allocations, otherwise they are refused. A heuristic quasi-optimal scheduling algorithm is proposed. Performance results show that significant benefits can be achieved with respect to traditional single-hop approaches