Minimum-Cost Optical Amplifier Placement in Metro Networks

Abstract

Emerging 5G services are revolutionizing the way operators manage and optimize their optical metro networks, and the metro network design process must be rethought accordingly. In particular, minimizing network cost is crucial to curb operators' investment. Taking advantage of relatively-short distances in metro networks, operators have the opportunity to optimize the placement of optical amplifiers (OAs) with the goal of minimizing amplifiers' cost (and hence decrease network cost) without significantly affecting the quality of transmitted optical signals. Minimizing OA cost translates not only in minimizing the cost of equipment (i.e., boosters, pre-amplifiers and inline amplifiers), but also in minimizing deployment and maintenance costs of active amplifier sites. In this paper, we propose a heuristic algorithm for OA placement and for the Routing and Spectrum Assignment (RSA) in metro networks, with the objective of minimizing the total cost of OAs while guaranteeing sufficient optical signal-to-noise ratio (OSNR) of established lightpaths. In our approach, we consider different cost for the deployed OAs, according to their location and type, i.e., inline amplifiers (ILAs), boosters and pre-amplifiers, and compare our optimized placement against benchmark strategies where OAs are predeployed at network nodes and at a fixed distance one from the other along optical fiber links. We also evaluate the impact of different routing strategies on the total cost and utilized spectrum. Simulative results, performed over realistic metro network topologies, show that our strategy provides up to 47% OAs cost savings while satisfying minimum OSNR constraints.

QoT-Aware Optical Amplifier Placement in Filterless Metro Networks

“…minCostGA vs Baseline: Results show significant savings in total OA cost achieved by GA in comparison to the baseline approach 5 . Specifically, the savings range between 45% and 60% for the 6-node topology and between 45% and 59% for the 11-node topology for the filterless horseshoe scenario (minCostGA-FON vs Baseline).…”

“…A lighthpath i is feasible if it meets the QoT requirements, i.e., the total OSNR (which also comprises the non-linear noise from the GN-model [8]) and received power (P rec ) constraints (OSN R i > threshold and P rec,i > threshold, as defined in Eq. 5and (6) in [5]). A solution is feasible if all lightpaths meet QoT requirements (thus f = 1), whereas a solution is unfeasible if there is at least one lightpath in set I which does not meet the OSNR and/or P rec constraint (f < 1).…”

“…Although the problem of OA placement has received attention for ROADM-based networks [4], [5], to the best of our knowledge, no study has been done in the context of filterless metro networks, where the presence of ASE accumulation makes solutions for OA cost minimization (as the one in [4], [5]) not applicable. Note that while in [5] the OA placement is done through an iterative greedy-approach; the GA ensures a dynamic exploration of teh search-space. Moreover, considering FON nodes implies adapting the physical layer modeling to account for the ASE noise propagation beyond lightpath termination.…”

Photonic Gateway and Protocol-Independent End-to-End Optical-Connection Provisioning in All-Photonic Metro-Access Converged Network

“…The path computation derives optimal transmission parameters and a route for each optical path, for example, using GNPy. At this stage, the optimal values of the gain of the cascaded optical amplifiers should be carefully recalculated so that addition or deletion of optical paths and changes in output power from transmitters do not affect the transmission quality of other existing optical paths [15][16][17][18]. In the second method, an SDN controller generates optical paths in a real or physical domain according to the results of the path computation.…”

Optical Metro Network Design with Low Cost of Equipment

“…Characteristics of EDFAs are taken from [4], and their gains are set to compensate propagation losses as in [7]. Received optical power (computed as in [7]) must be above -18 dBm, putting a constraint on OA placement.…”