Improving Performance of Spatially Joint-Switched Space Division Multiplexing Optical Networks via Spatial Group Sharing

Abstract

Space division multiplexing (SDM) is a promising approach to overcome the looming fiber capacity crunch. Joint and fractional joint switching (JoS and FJoS) architectures, which switch multiple spatial dimensions together as atomic units, have been proposed to reduce the cost of implementing SDM and cater to strongly coupled transmission media. However, they have been shown to impose significant penalties to overall network performance, at least when many relatively small connections are used in the context of uncoupled spatial dimensions, while performing nearly as well as the independent switching (InS) architecture if the average connection size is sufficiently large to efficiently exploit their increased granularity. In this work we tackle the performance penalty that JoS and FJoS architectures impose on SDM networks with uncoupled spatial dimensions compared to InS, by proposing two novel routing, space, and spectrum allocation (RSSA) heuristics that effectively share jointly switched resources, adapted to use different types of SDM reconfigurable optical add/drop multiplexer architectures requiring only a small additional cost. We investigate the performance of these new RSSA algorithms compared to an existing one under several traffic conditions and models using simulations. We find that our proposals can achieve significant improvements in the performance of SDM networks carrying large numbers of relatively small connections, up to parity of performance with InS designs, at a lower implementation cost, under all traffic conditions under study, including different average connection sizes and size diversity.

Impact of Spatial and Spectral Granularity on the Performance of SDM Networks Based on Spatial Superchannel Switching

“…In [16], we further showed that SG-Sw paradigms with lower G values perform well for networks with high level of traffic diversity, while J-Sw is favorable for networks with large demands. In addition, in [17], several algorithms have been proposed to improve the performance of different SDM switching paradigms when uncoupled fibers are in place. Note that in [15] [16], Ind-Sw, J-Sw and FrJ-Sw with G = 3 were only examined with a fixed spectral channel width (ChBW)defined as the spectrum over each of the spatial dimensions used to allocate the spatial Sp-Ch constituents-equal to 50 GHz.…”

Statistical Assessment of Open Optical Networks

“…UFRs are considered simply as a set of independent SMF whose nonlinear impairments are the same of single SMF and where independent switching (InS) [44] can be implemented. Here, however, we will apply the core continuity constraint (CCC) [45] switching technique also in UFRs.…”

“…The SNR improvement from NLM ∆SNR is derived according to the theory as [47]. However, SCMCFs require joint switching (JoS) implementation [44] due to the strong core coupling. This means that the add/drop of a channel and the LP allocation on a particular wavelength must be done on the same route and in all the cores [46,47].…”

“…This means that the add/drop of a channel and the LP allocation on a particular wavelength must be done on the same route and in all the cores [46,47]. Hence, while SCMCFs improve QoT, the need for JoS requires the implementation of advanced techniques of routing for space and spectrum assignment (RSSA) [44]; it reduces the total allocated traffic at a given BP [48]. Here, we do not consider advanced RSSA algorithms; we study only the NLM and switching techniques impact instead.…”

Dynamic Traffic Grooming in Joint Switching (JoS)-Enabled Flex-Grid/SDM Optical Core Networks

“…Depending on the traffic profile, it has been demonstrated that JoS performance can be significantly worse than that of InS 8 due to its spectrum wastage. In order to enhance it, some strategies have been proposed 6,9 . For example, e2e-grooming aims to reuse lightpaths for other demands having common source (s) and destination (t) nodes, always targeting a minimization when allocating them.…”