Dynamic provisioning utilizing redundant modules in elastic optical networks based on architecture on demand nodes (original) (raw)
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Proactive Fast Connection Recovery Scheme for a Failure in Elastic Optical Networks
2020
This paper presents a proposed link based fast connection recovery scheme for a failure in elastic optical network (EON). In this scheme a backup path is reserved in advance and re-route the traffic immediately after the failure happens in the network. This recovery scheme required large backup capacity. We analyse three network parameters such as bandwidth blocking probability (BBP), recovery time (RT), and network capacity utilization ratio (NCU) for randomly generated source to destination request for three topologies that is COST239, ARPANET and NSFNET and compare the results for shared link protection (SLP), dedicated link protection (DLP), and our proposed link based recovery scheme (PLBRS). Our proposed scheme shows the minimum RT compared to other two strategies.
Journal of Optical Communications and Networking, 2014
Elastic optical networks are envisaged as promising solutions to fulfill the diverse bandwidth requirements for the emerging heterogeneous network applications. To support flexible allocation of spectrum resources the optical network nodes need to be agile. Among the different proposed solutions for elastic nodes, the one based on architecture of demand (AoD) exhibits considerable flexibility against the other alternatives. The node modules in the case of AoD are not hard-wired, but can be connected/disconnected to any input/output port according to the requirements. Thus, each AoD node and the network (fabricated with AoD nodes) as a whole acts like an optical field-programmable gate array. This flexibility inherent in AoD can be exploited for different purposes, such as for cost-efficient and energy-efficient design of the networks. This study looks into the cost-efficient network planning issue for synthetic networks implemented through AoD nodes. The problem is formalized as an integer linear programming formulation for presenting the optimal solution. Furthermore, a scalable and effective heuristic algorithm is proposed for cost-efficient design, and its performance is compared with the optimal solution. The designed networks with AoD nodes are further investigated for a dynamic scenario, and their blocking probability due to limited switching resources in the nodes is examined. To alleviate the blocking performance for the dynamic case, an efficient synthesis strategy along with a scheme for optimal placement of switching resources within the network nodes is presented. Extensive results show that 1) even at high loads, the network with AoD nodes achieves saving of switching modules up to 40% compared to the one with static reconfigurable optical adddrop multiplexers (ROADMs) through a proper network design, 2) by diminishing the spectrum selective switches the overall power consumption of the network decreases by more than 25% for high loads, and 3) for the dynamic scenario the blocking owing to the node modules constraint is alleviated significantly by slightly augmenting the switching devices and optimally deploying them within the network nodes.
Journal of Lightwave Technology, 2000
In this paper, we present two adaptive schemes, namely, global differentiated availability-aware provisioning (G-DAP) and link-by-link differentiated availability-aware provisioning (LBL-DAP) for connection provisioning in optical transport networks under dual failure assumption. G-DAP attempts to determine a feasible sharing degree for each availability class for the links in the network globally. As an enhancement to G-DAP, LBL-DAP tries to determine a feasible sharing degree per availability class on each link. Connections belong to one of the five availability classes with the availability requirements of 0.98, 0.99, 0.999, 0.9999, and 0.99999, which are specified in their service level agreement (SLA). We compare the performance of the proposed schemes with a conventional service provisioning scheme, compute a feasible solution (CAFES) under the NSFNET and European optical network (EON) topologies. The simulation results show that the proposed schemes introduce better availability per connection and lower blocking probabilities. LBL-DAP performs the best by monitoring the shareability status of each link periodically with respect to the metrics studied, and decreases resource overbuild.
Capacity performance of dynamic provisioning in optical networks
IEEE/OSA Journal of Lightwave Technology, 2001
This paper describes an architecture and analyzes the performance of dynamic provisioning of lightpaths in an optical network. In dynamic provisioning, a lightpath is set up in real-time without rearranging the working and protection routes of existing lightpaths, and without the knowledge of future lightpath provisioning events. This paper develops a general model of the physical topology of the optical network, and outlines routing approaches for dynamic provisioning of lightpaths. It analyzes via simulations the performance of dynamically provisioned unprotected, 1 + 1 protected and mesh-restored lightpaths. The analysis of the efficiency of network utilization of dynamic provisioning focuses on the spare capacity needed for protection, and in particular focuses on the impact of sharing of wavelength channels for mesh-restored lightpaths. The main conclusion from the performance studies is that significant capacity gains are achieved with sharing of wavelength-channels for mesh-restored lightpaths with dynamic provisioning even for sparse topologies, and even at moderate loads.
Journal of Lightwave Technology, 2018
As Elastic Optical Networks (EONs) are expected to convey high bitrate connections, a failure in these networks causes vast data losses. Thus, addressing the problem of survivability in EONs is of great importance. In this paper, survivability of an EON with multiclass traffic is investigated, where each traffic type needs specific protection mechanism and scheduling strategy. In particular, a connection request may demand for dedicated path protection (DPP), shared backup path protection (SBPP), or restoration mechanism. Besides, it can tolerate a predetermined delay and be scheduled at future time slots, referred to as Advance Reservation (AR), or must be served immediately without any delay, referred to as Immediate Reservation (IR). Accordingly, we formulate an Integer Linear Programming (ILP) to solve the routing, spectrum and modulation level assignment, and scheduling problems in both static and dynamic operation scenarios. In addition, to reduce the complexity of the ILP formulation in large scale networks, we propose a number of heuristic algorithms, in which two and three methods are considered for path selection and resource allocation, respectively. We evaluate the proposed heuristic algorithms in a small scale network by comparing their performance with the ILP formulation, then we apply them in a realistic large scale network. We compare all algorithms in terms of blocking probability, initial delay, and spectrum efficiency. Our results reveal that by using loadaware path selection and first-fit frequency-slice and time-slot assignment strategies the best compromise between blocking probability and initial delay is obtained.
A Proactive Link Based Fast Recovery Strategy for Survival Elastic Optical Networks
International Journal of Engineering and Advanced Technology, 2020
In this paper, we proposed a link based fast connection recovery strategy. A backup path either reserved in advance or searched dynamically after the failure occurred in the network. Both these recovery strategy required large backup capacity. We analyse three network parameters such as recovery time (RT), bandwidth blocking probability (BBP), and network capacity utilization ratio (NCU) for randomly generated source to destination request for three topologies that is COST239, ARPANET and NSFNET and compare the results for shared link protection (SLP), dedicated link protection (DLP), and our proposed link protection (PLP) scheme. Our proposed scheme shows the minimum RT compared to other two strategies.
Sensors, 2024
In this paper, we investigate a scenario in which protected and unprotected services coexist in an elastic optical network under dynamic traffic. In the investigated scenario, unprotected services can reuse the reserved idle bandwidth to provide protection to the protected services. Under this scenario, we propose a new heuristic algorithm that enables such reuse as well as define and introduce a new assignment problem in elastic optical networks, named a Transmission Spectrum Assignment (T-SA) problem. In this paper, we consider a scenario in which services may be routed using the multipath routing approach. Additionally, protection using bandwidth squeezing is also considered. We assess our proposal through simulations on three different network topologies and compare our proposal against the classical protection approach, in which bandwidth reuse is not allowed. For the simulated range of network loads, the maximum (minimum) blocking probability reduction obtained by our proposal is approximately 48% (10%) in the European topology, 46% (7%) in the NSFNET topology, and 32% (6%) in the German topology.
Idle Protection Capacity Reuse in Multiclass Optical Networks
Journal of Lightwave Technology, 2000
Optical networks carrying traffic belonging to different survivability classes must ensure not only the proper survivability differentiation but also the efficient network resource utilization. Current approaches improve network resource utilization by carrying low-class preemptable traffic along highclass spare resources, which are idle (i.e., unutilized) during failure-free conditions. In this paper, the proposed idle protection capacity reuse (IR) framework generalizes the practice of reutilizing idle spare resources to both failure-free and failure conditions. The IR framework is based on the idea of exploiting idle high-class lightpath protection resources not only for routing low-class lightpaths during the provisioning phase (i.e., provisioning-phase IR, P-IR) but also for dynamically restoring low-class lightpaths during the recovery phase (i.e., recovery-phase IR, R-IR). Both P-IR and R-IR have the potential to improve network utilization while providing multiclass lightpaths with the required survivability differentiation. The numerical evaluation shows that the utilization of R-IR in dynamic restoration results in an improved low-class lightpath survivability with respect to the utilization of stub release. Moreover, if P-IR and R-IR are alternatively exploited, then the former improves the provisioning performance, while the latter guarantees a higher survivability. In the end, if P-IR and R-IR are concurrently employed in the provisioning and in the dynamic restoration of two different low classes of lightpaths, respectively, an inherent survivability differentiation is achieved.
Availability and Operability in Optical Transport Network Architectures
2020
A typical optical transport network interconnects multitudes of offices. With the advent of the Internet of Things (IoT) networking approach, it has become necessary for such transport structures to be flexible enough to accommodate heterogeneous communication services that generate escalating traffic loads every time. It is also key not only to accommodating continuously escalating traffic levels, but also to maintain a consistent Quality of Service, operability as well availability. This can only be achieved through the provisioning of effective and dynamic network control. In this paper, we explore the various operational issues such as incompatibilities in terms of physical layer transmission requirements and other control and management challenges emerging in present and future/ (envisaged) optical transport networks.
New Dimensions for Survivable Service Provisioning in Optical Backbone and Access Networks
Advances in Fault-Tolerant Methodologies
Originally, networks were engineered to provide only one type of service, i.e. either voice or data, so only one level of resiliency was requested. This trend has changed, and today's approach in service provisioning is quite different. A Service Level Agreement (SLA) stipulated between users and service providers (or network operators) regulates a series of specific requirements, e.g., connection setup times and connection availability that has to be met in order to avoid monetary fines. In recent years this has caused a paradigm shift on how to provision these services. From a "one-solution-fits-all" scenario, we witness now a more diversified set of approaches where trade-offs among different network parameters (e.g., level of protection vs. cost and/or level of protection vs. blocking probability) play an important role. This chapter aims at presenting a series of network resilient methods that are specifically tailored for a dynamic provisioning with such differentiated requirements. Both optical backbone and access networks are considered. In the chapter a number of provisioning scenarios-each one focusing on a specific Quality of Service (QoS) parameter-are considered. First the effect of delay tolerance, defined as the amount of time a connection request can wait before being set up, on blocking probability is investigated when Shared Path Protection is required. Then the problem of how to assign "just-enough" resources to meet each connection availability requirement is described, and a possible solution via a Shared Path Protection Scheme with Differentiated Reliability is presented. Finally a possible trade off between deployment cost and level of reliability performance in Passive Optical Networks (PONs) is investigated.