Translucent Elastic Optical Networks Research Articles

DRAMA+: Disaster Management With Mitigation Awareness for Translucent Elastic Optical Networks

Elastic optical networks (EONs) have emerged as attractive candidates to satisfy the dramatic growth of demand in 5G and cloud applications. EONs promise to provide high spectrum utilization due to flexibility in resource assignment. In translucent EONs, the spectrum efficiency can be further improved by deploying regenerators. Because of their extremely high flexibility, developing efficient mechanisms and strategies to ensure the survivability of translucent EONs is a challenging problem. In this paper, we consider disaster mitigation in translucent EONs. We propose a new approach to disaster management by introducing the concept of mitigation zone, which identifies a region surrounding the disaster zone wherein lightpaths may be reconfigured with degraded service (with a penalty) in order to improve overall performance. We formulate an integer linear program (ILP) to minimize the penalty due to service degradation after a disaster, and present a heuristic algorithm named Disaster Management Algorithm with Mitigation Awareness and 3R regenerators (DRAMA+). Simulation results demonstrate that the proposed algorithms have a better performance in terms of total penalty and blocking ratio than conventional disaster recovery algorithms.

Link-protection and FIPP p-cycle designs in translucent elastic optical networks

Elastic optical networks (EONs) are able to provide high spectrum utilization efficiency due to flexibility in resource assignment. In translucent EONs, by employing regenerators and using advanced modulation formats for transmission, spectrum efficiency can be further improved. Survivability is regarded as an important aspect of EONs, and p-cycle protection is considered to be an attractive scheme due to its fast restoration and high protection efficiency. In this paper, we propose methods for evaluating and selecting p-cycles for both link protection (LP) and failure-independent path protection (FIPP) to survive single-link failures. After considering the various factors that affect the performance of a p-cycle, we propose two evaluation metrics for LP and FIPP, namely, individual p-cycle cost and set of cycles cost. Based on these metrics, we propose two algorithms for selecting a set of p-cycles in translucent EONs: Traffic Independent P-cycle Selection (TIPS), which selects a set of cycles without knowledge of the traffic, and Traffic-Oriented P-cycle Selection (TOPS), which takes given traffic information into account. A routing and spectrum assignment algorithm is designed for translucent EONs, and our p-cycle design algorithms are evaluated using both static and dynamic traffic models. Simulation results show that the proposed algorithms have better performance than commonly used baseline algorithms. We also compare the performance of LP p-cycles and FIPP p-cycles.

On the performance of online routing enabled translucent space division multiplexing-based elastic optical networks

On the performance of online routing enabled translucent space division multiplexing-based elastic optical networks

On the performance of online routing enabled translucent space division multiplexing-based elastic optical networks

We focus on lightpath optimisation in a space division multiplexing-based elastic optical network by proposing the online routing algorithm with regeneration algorithm which accounts for the presence of transceivers in the network, and also ensures routing of translucent lightpaths through spectral super-channels over spatial multiple core fibres links. In regard to regeneration, we investigate three different scenarios which differ in their regeneration variability level in addition to the adjustment of modulation formats according to the transmission route characteristics. We conduct extensive simulations considering two realistic network topologies and two different multiple core fibre crosstalk values which result in different transmission reach values. The obtained results demonstrate that the proposed algorithm significantly outperforms the various reference routing techniques, and significant benefits can be obtained in regard to the utilisation of resources with much lesser BwBP when regeneration is conducted with complete flexibility and modulation format conversion is permitted at every network node.

Assessment of novel regenerator assignment strategies in dynamic translucent elastic optical networks

The problem of regenerator assignment (RA) in translucent optical networks consists in segmenting a lightpath into several transparent segments, each of which linked by 3 R regenerators. In this article, we present two heuristics and compare their effectiveness with an exhaustive method to solve the RA problem in translucent elastic optical networks under dynamic traffic. The exhaustive method is capable of finding solutions that are able to minimize, simultaneously, the number of regenerators and frequency slots used in a given route. It is assumed 3 R regenerators, which are capable to perform both modulation format and spectrum conversion. In our simulations, we consider the amplified spontaneous emission noise generated by optical amplifiers as physical impairment. Two practical mesh topologies have been analyzed in terms of call request blocking probability. The results show that the presented heuristics are able to find solutions that provide very similar performance to those found by utilizing the best solutions of the exhaustive method.

An auxiliary-graph-based methodology for regenerator assignment problem optimization in translucent elastic optical networks

Abstract In this article, we propose an auxiliary-graph-based methodology to best assess regenerator assignment choices in translucent elastic optical networks. The proposed methodology considers that each possible transparent segment in a route is represented by an edge in an auxiliary graph. Proper edge cost functions are designed and the decision on where to use regeneration resources is performed by a standard routing algorithm in the built auxiliary graph. We propose four different edge cost functions and compare the performance, in terms of blocking probability of call requests, of some networks using our proposed methodology and other heuristics available in the literature that tackle with regenerator assignment problem in translucent elastic optical networks. The simulation scenarios involved three different network physical topologies, amplified spontaneous emission noise as physical impairment generated by boosters, in-line amplifiers and pre-amplifiers, besides losses and gains observed by the optical signals along network lightpaths. By properly defining the respective edge cost function, our proposed methodology can not only replicate some heuristics previously proposed in the literature, but also create strategies that present superior performance in all analyzed scenarios and conditions.

On Performance Gains of Flexible Regeneration and Modulation Conversion in Translucent Elastic Optical Networks With Superchannel Transmission

We study potential performance gains resulting from deliberate use of signal regeneration along with modulation and spectrum conversion in translucent elastic optical networks, realizing superchannel transmission. We analyze three alternative scenarios that differ in the way in which translucent lightpath connections are provisioned. Namely, a basic one in which the use of regenerators is minimized and two other cases that are more flexible in terms of signal regeneration and modulation conversion. To compare these scenarios, we focus on the problem of routing, spectrum, transceiver, and regeneration allocation (RSTRA). In RSTRA, in addition to classical RSA constraints, the selection of regeneration sites together with adaptation of modulation formats and assignment of transceivers to lightpaths is taken into account. To formulate the RSTRA optimization problem, we apply the integer linear programming approach, and to generate RSTRA solutions, we develop a heuristic algorithm. The results of numerical experiments show that intentional signal regeneration and adaptation of modulation formats of optical carriers can be beneficial in terms of both spectrum and transceivers utilization in long-distance networks; however, the savings are negligible in a small-distance network.

Scalable Framework for Translucent Elastic Optical Network Planning

Scalable Framework for Translucent Elastic Optical Network Planning

Impact of Wavelength and Modulation Conversion on Translucent Elastic Optical Networks Using MILP

Compared to legacy wavelength division multiplexing networks, elastic optical networks (EONs) have added flexibility to network deployment and management. EONs can include previously available functionality, such as signal regeneration and wavelength conversion, as well as new features such as finer-granularity spectrum assignment and modulation conversion. Yet each added feature adds to the cost of the network. In order to quantify the potential benefit of each functionality, we present a link-based mixed-integer linear programming (MILP) formulation to solve the optimal resource allocation problem. We then propose a recursive model in order to either augment existing network deployments (spectrum and regenerators) or speed up the resource allocation computation time for larger networks with higher traffic demand requirements than can be solved using an MILP. We show through simulation that systems equipped with signal regenerators or wavelength converters require a notably smaller total bandwidth, depending on the topology of the network. We also show that the suboptimal recursive solution speeds up the calculation and makes the running time more predictable, compared to the optimal MILP.