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This paper demonstrates the first field trial of autonomous lightpath provisioning over a space-division multiplexing (SDM) optical network built with 16.5-km 7-core fibers. In particular, we devised an amplifier gain configuration algorithm aided by a composable quality-of-transmission (QoT) estimator. The composable QoT estimator allows per-span impairment assessment, and therefore, enables sequential gain optimization without the need for data plane trial and error. For each amplifier, the algorithm picks a solution that maximizes the overall QoT margin obtained for both in-service and newly established lightpaths. We trained the QoT estimator with data collected from the field testbed and conducted lightpath provisioning experiments under multiple scenarios (using different routing, modulation formats and baud rates). We also demonstrated automated failover operations in the cases of equipment failure and receiver filter shifting. Results show that the proposed design can accomplish lightpath configuration/failover autonomously in around 10 seconds while securing desired QoT levels.

Due to the advantages of optical circuit switching (OCS), all-optical data center networks (DCNs) have attracted intensive research interests recently. Hyper-FleX-LION is a highly-flexible all-optical DCN architecture that operates with the OCS based on wavelength-division multiplexing (WDM). In this work, we study how to realize traffic-aware configuration of all-optical DCNs in Hyper-FleX-LION. We formulate an integer linear programming (ILP) model for the problem to jointly optimize the configuration of Hyper-FleX-LION and the provisioning schemes of demands in it for minimizing its port usage. To ensure the practicalness of the optimization, we assume that each top-of-rack (ToR) switch can not only receive the traffic targeting to its rack but also forward traffic to other racks as an intermediate node. We also classifier traffic demands as normal and latency-sensitive ones, and set the maximum hop-count for routing latency-sensitive demands. By analyzing the complexity of the problem theoretically, we prove its $\mathcal {APX}$ -hardness, i.e., there does not exist a polynomial-time approximation algorithm for it unless $\mathcal {P}=\mathcal {NP}$ . Then, we propose a polynomial-time heuristic JTRO based on iterative optimization to solve the problem effectively and time-efficiently. Extensive numerical simulations verify the effectiveness of our proposed algorithm. We also build a small-scale but real all-optical DCN testbed in Hyper-FleX-LION to interconnect four racks, and leverage distributed machine learning (DML) as the network services in it to demonstrate the performance of our proposal experimentally.

The rapid development of emerging network services are shifting the major communication scheme in metro-aggregation networks from unicast to in-cast and multicast, which has promoted the development of the point-to-multipoint coherent optical transceivers (P2MP-TRXs). Meanwhile, for its cost-effectiveness and energy-efficiency, filterless optical network (FON) has been considered as a promising optical infrastructure for metro-aggregation networks, and it is naturally compatible with P2MP-TRXs because they both rely on the broadcast-and-select scheme for communications. In this paper, we study the problem of survivable multilayer planning of FONs with P2MP-TRXs and design algorithms to ensure that the planned FON can protect itself against single-link failures. We first formulate a mixed integer linear programming (MILP) model to jointly optimize the routing of working and backup lightpaths of traffic demands, and the allocation of P2MP-TRXs, assignment of subcarriers (SCs) to P2MP-TRXs, spectrum assignment on fiber trees for setting up the lightpaths, such that the capital expenditures (CAPEX) of the planned FON is minimized. Then, to solve the problem more time-efficiently, we propose a polynomial-time heuristic based on auxiliary graphs (AGs) and lightpath grouping. Extensive simulations verify the performance of our proposals and indicate that they can outperform existing benchmarks.

Recently, to cope with the ever-growing traffic volumes and network services in the Internet, the coherent point-to-multipoint transceivers (P2MP-TRXs) enabled by digital subcarrier modulation (DSCM) technique have been developed and viewed as a promising replacement of conventional point-to-point transceivers (P2P-TRXs), especially for the metro-aggregation networks with hub-and-spoke traffic patterns. Nevertheless, the network planning of wavelength switched optical networks (WSONs) with P2MP-TRXs can be rather complex, as additional correlated constraints are introduced to model the routing and spectrum assignment (RSA), and thus the problem cannot be solved with existing algorithms in the literature. In this article, we study the network planning of WSONs with P2MP-TRXs, which not only includes the aforementioned subproblem of correlated RSA, but also the placement of P2MP-TRXs in hub-leaf-based groups and the corresponding subcarrier (SC) assignments. We first formulate an integer linear programming (ILP) model to formally describe and exactly solve the network planning problem. Then, two polynomial-time heuristics, based on layered auxiliary graph (LAG) and conflict graph (CG), respectively, are proposed to find near-optimal solutions. Finally, we perform extensive simulations to evaluate the proposed algorithms, and the simulation results confirm their performance and effectiveness.

With enhanced cost-effectiveness, filterless optical networks (FONs) have been considered as a promising candidate for future optical infrastructure. However, as the transmission in FON relies on the “select-and-broadcast” scenario, it is more vulnerable to eavesdropping. Therefore, encrypting the communications in FONs will be indispensable, and this can be realized by introducing the optical transport network (OTN) encryption technologies that leverage high-speed encryption cards (ECs) to protect the integrity of OTN payload frames. In this paper, we study the problem of security-aware multilayer planning of FONs with OTN encryption. We first formulate a mixed integer linear programming (MILP) model (i.e., w-MILP) to solve the problem exactly. Then, to reduce the time complexity of problem-solving, we transform w-MILP into two correlated MILP models for establishing fiber trees for an FON (t-MILP) and planning flows in the fiber trees (s-MILP), respectively. The optimization in t-MILP is further transformed into a weighted set partitioning problem, which can be solved time-efficiently. As for s-MILP, we propose a polynomial-time approximation algorithm based on linear programming (LP) relaxation and randomized rounding. Extensive simulations verify the performance of our proposals.