Virtual Channel Transmission for Zero-Jitter Deterministic Scheduling in WDM Slot Switching Xhaul

In this presentation we discuss the support for deterministic scheduling in WDM Slot Switching Xhaul. In WDM Slot Switching network called N-GREEN the WDM slots carry the payload data units (PDUs) over parallel wavelengths, in a time slotted manner. Such network design enables savings in cost and energy consumption w.r.t. the state of the art electronic packet switching technologies through the optical parallelization. The subsequent time slots in N-GREEN are separated by a fixed guard time interval, to achieve the separation and switching of individual WDM slots. We show that under this assumption it is possible to provide zero-jitter transmission of isochronous traffic, that is present in 5G Xhaul, irrespective of the size of the guard time. In finding the solution, we first observe the properties of isochronous traffic, and we then introduce "virtual channel transmission" for WDM Slot Switching network as a new method for enabling zero-jitter transmission of time-sensitive traffic in this network segment. The scheduler is first implemented by using linear programming and next, a scalable implementation of the same scheduler is presented in form of a greedy algorithm. The numerical results confirm the cost and energy consumption savings of N-GREEN network, when compared with Ethernet state of the art solution, for time-sensitive traffic, while zero-jitter deterministic scheduling is achieved. We discuss also the perspectives of this work and show preliminary ns3 simulation results for a more detailed performance evaluation and advanced schedulers in N-GREEN.