Control-plane congestion and provisioning guidelines for OBS networks

We present the first detailed analysis of the potential effects of electronic-control-plane throughput limitations on the overall loss and latency performance of OBS networks. We present an accurate analytical model for the header queuing process in core nodes taking into account the finite delay budget imposed by the header-offset size. We examine in detail the role of burst length and offset size on control-plane congestion and loss, and we provide a set of design guidelines for provisioning them such that the control-plane does not become the throughput bottleneck of the system. We find that ultra-fast header-processing speeds (< 100 ns per header) are not required for efficient OBS operation. We also show that provisioning a header-offset size that corresponds to a header-queue length of 50 is sufficient for realizing negligible control-plane loss and supporting burst lengths as small as megabits or hundreds of kilobits for OBS systems with up to 512 wavelengths.