Immediate Reservation Research Articles

Resource Allocation Scheme Based on Complete Planning Process for Immediate and Advance Reservation in SDM-EONs

Immediate reservation (IR) and advanced reservation (AR) become two common traffic models for future space division multiplexing-elastic optical networks (SDM-EONs). However, it is crucial to reduce conflicts between different types of requests and to accommodate more requests with limited resources. In this paper, we propose a resource allocation scheme based on complete planning process (RA-CPP) for IR and AR in SDM-EONs, including request provisioning, resource planning, passive adjustment, and active adjustment. In the request provisioning, the starting time of requests is considered and the earlier transmitted requests have higher resource selection priority. Next, the spectrum blocks with minimal resource spacing between adjacent requests (RS-AR) are planned for requests to maximize the free resources of the network in the resource planning. In addition, for the new request that would be blocked, passive adjustment begins. After planning reserved resources for the new request, conflicting AR requests are re-provisioned. Finally, the active adjustment re-optimizes the resources by increasing the tightness of spectrum resources. Simulation results show that the proposed RA-CPP scheme has greater advantages in blocking probability and spectrum utilization compared with the benchmark schemes.

A Survey of Minimum Wavelength Conversion Routing and Wavelength Assignment in WDM Networks

Generally, research on routing and wavelength task over wavelength directed WDM networks is worried about immediate reservation (IR) requests. An IR demand typically does not specify a holding time for data transmission and the start time of the data transmission are assumed to be immediate (i.e. when the connection request arrives). The idea of advance reservation (AR) has as of recently been picking up consideration for optical networks. An AR request commonly determines data about the beginning of the information transmission or a cutoff time, just as the holding time of the transmission. AR has a few significant applications for both wide-region networks and Grid networks. For instance, AR can be utilized for modifying virtual geographies to adjust to predictable peak hour traffic use. It very well may be utilized to give high- bandwidth transmission administrations, for example, video conferencing and in Grid applications requiring the booked circulation of enormous records and for co-allotment of organization and grid assets. AR can likewise be advantageous to the organization by permitting the organization administrator to more readily design asset use and accordingly increment use. Information on the holding time can prompt more ideal choices for asset distribution. This translates to better quality of service for users. In this paper we give a complete study of the past and current work on booking ahead of time for optical organizations. There have been numerous varieties of the advance reservation of time idea proposed, so we will likewise give an expansive grouping. Notwithstanding the review, we will examine what we accept are significant regions of future work and open difficulties for early booking on optical organizations. Keywords: Advance reservation, scheduled demands, WDM, survey, wavelength-routed, and RWA

Time and spectrum fragmentation-aware virtual optical network embedding in elastic optical networks

Abstract Based on the concept of infrastructure as a service, optical network virtualization can improve the efficiency of network infrastructure by sharing the physical substrate network among different tenants and applications. The most important issue of optical network virtualization is how to handle the virtual optical network embedding (VONE) process, especially with the coexistence of the requests those can be reserved in advance (AR) and those require immediate reservation (IR). To address this issue, we investigate the time and spectrum fragmentation during the VONE process, which undermines the embedding success rate in elastic optical networks. A two-dimensional fragmentation measurement is first proposed to evaluate the resource state. Then we design a Two-Dimensional Fragmentation Aware (TDFA) VONE algorithm, and a Fragmentation and Continuity Aware (FCA) VONE algorithm, which decreases the two-dimensional fragmentation in the VONE process. Simulation results show that the proposed algorithms perform better than the baseline algorithm in blocking probability and spectrum utilization issues.

Transductive Transfer Learning-Based Spectrum Optimization for Resource Reservation in Seven-Core Elastic Optical Networks

In space-division multiplexing elastic optical networks (SDM-EONs), it is important to handle the complex resource optimization (RO) problem due to the coexistence of the requests that require immediate reservation (IR) and those that can be reserved in advance (AR). The introduction of artificial intelligence, especially machine learning algorithms, has made it possible to design more effective RO strategies. However, the model trained by current machine learning algorithms is only suitable for specific scenarios, and cannot be applied to new scenarios, resulting in the need to retrain the models in the new scenario and increase the training costs. Transfer learning (TL) can solve this problem by collecting a small amount of training data in the new scenario and strengthening the existing related models. This paper proposes a RO strategy for resource reservation based on TL in SDM-EONs. If the AR requests fail to reserve resources, TL will be used to predict the spectrum defragmentation time to complete the resource optimization before their start time. For the IR requests, they will occupy the low-level AR requests with the latest start time. Simulation results indicate that the proposed algorithm can decrease the probability for resource reservation failure and improve the resource utilization.

Crosstalk-aware spectrum defragmentation by re-provisioning advance reservation requests in space division multiplexing enabled elastic optical networks with multi-core fiber.

Space division multiplexing enabled elastic optical networks (SDM-EONs) with multi-core fiber (MCF) have become a promising candidate for future optical transport networks, due to their high capacity and flexibility. Meanwhile, driven by the development of cloud computing and data centers, more types of requests are allowed in the networks, i.e., the usual immediate reservation (IR) requests, which need to be served immediately, and advance reservation (AR) requests, which support initial-delay tolerance services. However, with the introduction of AR requests, spectrum fragments occur frequently in both spatial and time dimension as lightpaths are set up and torn down, and the issue of spectrum fragmentation could be much more serious in SDM-EONs than in simple EONs. To measure fragments status in both spatial and time dimension in SDM-EONs, we first design a metric, i.e., time-dimensional spectrum compactness (TSC). Then, based on TSC, we propose a crosstalk-aware AR requests re-provisioning algorithm with two strategies to optimize the fragments in SDM-EONs. The performance of the proposed algorithm is evaluated via software simulation in terms of spectrum compactness, blocking probability, spectrum utilization, average moving times, average re-provisioning latency and average start time delay. The results show that the proposed re-provisioning algorithm can effectively improve spectrum compactness and spectrum efficiency of the networks. We also evaluate the proposed re-provisioning algorithm in different TSC thresholds, and it turns out that the proposed re-provisioning algorithm in higher threshold performs better in terms of spectrum compactness and spectrum utilization.

Re-Provisioning of Advance Reservation Applications in Elastic Optical Networks

Driven by the development of cloud computing and mobile Internet, network-based applications have become diverse. Besides the usual immediate reservation (IR) applications, which need to be served immediately, advance reservation (AR) applications have been introduced to support initial-delay-tolerance services, such as grid computing, virtual machine backup, and so on. The provisioning mechanism of AR applications is different from that of IR applications, because AR requests don’t require to be served immediately, and the network operator must decide the exact serving time in the AR service provisioning process. Based on the scheduling features of AR requests, this paper formulates a resource model and sets up a control framework for elastic optical networks to support AR services. We propose an optimization algorithm with three reprovisioning policies to dynamically reprovision the AR applications, which have already been scheduled. Both the proposed control framework and algorithm are developed on the basis of an open network operating system, which is an open-source software-defined networking controller. Also, the performance of the proposed algorithm is evaluated via software simulation. Demonstration results show the benefits of reprovisioning, and simulation results show that the reprovisioning optimization algorithm can improve the efficiency of network spectrum resource.

Dynamic time and spectrum fragmentation-aware service provisioning in elastic optical networks with multi-path routing

Abstract In this paper, we propose a multi-path fragmentation-aware routing, modulation and spectrum assignment algorithm (RMSA) for advance reservation (AR) and immediate reservation (IR) requests in elastic optical networks. Immediate reservation requests should be provided with service immediately, while advance reservation requests have specific starting times and holding times. As lightpaths are set up and torn down, fragmentation may occur in both spectrum and time domains. To decrease the two-dimensional fragmentation and to solve the problem of resource scarcity, we propose splitting requests into different parts and transferring these parts along one or more paths utilizing sliceable bandwidth variable transponders. We first introduce a model to solve the problem and propose a two-dimensional fragmentation occurrence measurement in spectrum and time domains. Then we propose a multi-path fragmentation-aware RMSA algorithm (MPFA). Simulation results show that MPFA can achieve better performance than existing algorithms in terms of blocking probability and spectrum utilization.

Cross-stratum resource reservation (CSRR) algorithm for deadline-driven applications in datacenter networks

Nowadays, datacenters interconnected with optical networks have become the fundamental infrastructure to accommodate high-performance datacenter applications. Lacking of layer interaction between datacenters and networks during service provisioning, many end user applications cannot efficiently utilize the network capabilities, nor can they achieve the desired quality of service objectives. In response to these challenges, cross-stratum optimization has been studied to optimize the computing and network resources utilization from a united view. Meanwhile, the type of network applications becomes diverse. Compared to traditional immediate reservation (IR) request, a new type of request called advance reservation (AR) has recently been gaining attention for optical networks. IR's start time of data transmission is assumed to be immediate, while AR request typically specifies the earliest time or the deadline of data transmission. According to the time features of AR request, AR applications should be scheduled in time dimension. Thus, it is both important and challenging to reserve computing and network resources in efficient manners. In this study, a cross-stratum resource model considering time dimension is set up, and a cross-stratum resource reservation (CSRR) algorithm is proposed to schedule AR applications and to reserve cross-stratum resource. Simulation results show that CSRR can reduce the failure rates of AR applications and improve the resource consumption ratio significantly.

On Hybrid IR and AR Service Provisioning in Elastic Optical Networks

This paper investigates hybrid immediate reservation (IR) and advance reservation (AR) service provisioning in elastic optical networks, with the objective to minimize IR/AR service conflicts. We design algorithms to coordinate service provisioning of IR and AR requests. Specifically, both proactive and reactive IR provisioning schemes are considered to minimize IR service failures. Our AR scheduling algorithm can coordinate AR service provisioning with various IR traffic patterns, balance spectrum utilization in both time and spectral domains, and reduce IR/AR service conflicts. Simulation results verify that our proposed IR + AR schemes can significantly reduce IR service failures as well as routing and spectrum allocation reconfigurations in IR service provisioning. Moreover, the results indicate that the proposed IR + AR schemes can achieve more performance gain from AR flexibility when compared with two existing benchmarks.

Analytical Blocking Probability Model for Hybrid Immediate and Advance Reservations in Optical WDM Networks

Immediate reservation (IR) and advance reservation (AR) are the two main reservation mechanisms currently implemented on large-scale scientific optical networks. They can be used to satisfy both provisioning delay and low blocking for delay-tolerant applications. Therefore, it seems reasonable that future optical network provisioning systems will provide both mechanisms in hybrid IR/AR scenarios. Nonetheless, such scenarios can increase the blocking of IR if no quality-of-service (QoS) policies are implemented. A solution could be to quantify such blocking performance based on the current network load and implement mechanisms that would act accordingly. However, current blocking analytical models are not able to deal with both IR and AR. In this paper, we propose an analytical model to compute the network-wide blocking performance of different IR/AR classes within the scope of a multiservice framework for optical wavelength-division multiplexing (WDM) networks. Specifically, we calculate the blocking on two common optical network scenarios using the fixed-point approximation analysis: on wavelength conversion capable and wavelength-continuity constrained networks. Performance results show that our model provides good accuracy compared to simulation results, even in a scenario with multiple reservation classes defined by different book-ahead times.

A Survey of Advance Reservation Routing and Wavelength Assignment in Wavelength-Routed WDM Networks

Traditionally, research on routing and wavelength assignment over wavelength-routed WDM networks is concerned with immediate reservation (IR) demands. An IR demand typically does not specify a holding time for data transmission and the start time of the data transmission is assumed to be immediate (i.e. when the connection request arrives). The concept of advance reservation (AR) has recently been gaining attention for optical networks. An AR demand typically specifies information about the start of the data transmission or a deadline, as well as the holding time of the transmission. AR has several important applications for both wide-area networks and Grid networks. For example, AR can be used for adjusting virtual topologies to adapt to predictable peak hour traffic usage. It can be used to provide high-bandwidth services such as video conferencing and in Grid applications requiring the scheduled distribution of large files and for co-allocation of network and grid resources. AR can also be beneficial to the network by allowing the network operator to better plan resource usage and therefore increase utilization. Knowledge of the holding time can lead to more optimal decisions for resource allocation. This translates to better quality of service for users. In this paper we provide a comprehensive survey of the past and current work on advance reservation for optical networks. There have been many variations of the advance reservation concept proposed, so we will also provide a broad classification. In addition to the survey, we will discuss what we believe are important areas of future work and open challenges for advance reservation on optical networks.