Virtual Optical Link Research Articles

Virtual optical network embedding of time-varying traffic in elastic optical networks

Network virtualization can enhance the flexibility of Internet infrastructure resources and the scalability of the substrate elastic optical networks (EONs) through the coexistence of multiple virtual optical networks supporting different services. Traditional virtual optical network embedding mostly assumed fixed embedding, that is, once a virtual optical network (VON) is embedded, the network resources allocated to it are almost unchanged during its lifetime. However, the actual traffic demand on a VON usually changes over time. To address the problems of high bandwidth blocking probability and low spectrum utilization caused by the mismatch between the resources allocated and the required resources during the virtual optical network embedding of the time-varying traffic in the elastic optical networks (EONs), we propose a virtual optical network embedding algorithm of the time-varying traffic (TVT-VONE). Firstly, in the node embedding stage, a node weight value measurement is designed based on the attributes of virtual nodes and physical nodes. Secondly, in the virtual optical link embedding stage, a measurement formula for path spectrum resource richness is designed to decrease link embedding failure due to insufficient spectrum resources on the path. Finally, in order to adapt to the characteristics of dynamic changes in bandwidth requirements of time-varying traffic, we design a resource-aware virtual network reconfiguration strategy when the spectrum resources of traffic required do not match the resources allocated to the changed traffic. Simulation results show that the proposed algorithm can effectively reduce the bandwidth blocking probability of VON requests and improve spectrum utilization of EONs.

A survivable VON embedding algorithm based on resource mean and spectrum coherence-aware in elastic optical networks

Abstract To address the problems of severe spectrum fragmentation and high bandwidth blocking probability of virtual optical network embedding in elastic optical networks, we propose a survivable virtual optical network embedding algorithm based on resource mean and spectrum coherence-aware (SVONE-RMSC). Firstly, according to the lightpath spectrum resources state of candidate substrate nodes to the correlative substrate nodes that have been embedded, we design the spectrum resource mean formula to enhance the correlation between virtual node embedding and virtual optical link embedding. Secondly, the algorithm optimizes the spectrum allocation methods. Specifically, to weaken the disruption of spectrum allocation to the spectrum continuity of the working lightpaths, the formula of spectrum coherence is designed. When allocating the spectrum resources for the protection lightpaths, we propose a spectrum allocation method based on spectrum coherence-aware, so as to maximize the spectrum coherence while minimizing the free frequency slots consumption. Finally, when the lack of spectrum resources on the single lightpath leads to the failure of virtual optical link embedding, different path splitting methods are designed to re-embed the virtual optical link. Simulation results show that the SVONE-RMSC algorithm can effectively reduce the bandwidth blocking probability and enhance the spectrum utilization.

A coordinated virtual optical network embedding algorithm based on resources availability-aware over elastic optical networks

Abstract Recent innovations in network virtualization and elastic optical networks enable the flexible deployment of optical networks. However, the spectrum fragmentation and virtual optical links being embedded to the longer lightpaths decrease the spectrum efficiency of elastic optical networks. To address this issue, a coordinated virtual optical network embedding algorithm based on resources availability-aware (RA-CVONE) is proposed. Firstly, we design the node importance metric to embed the neighboring virtual nodes to the closer physical nodes, and then a coordinated embedding approach is adopted, which can further shorten the length of the lightpaths to which virtual optical links are embedded. Moreover, we jointly evaluate the resources availability of a physical lightpath and its node, then select the candidate lightpaths with less spectrum fragmentations and abundant resources for a virtual optical link. Based on the resources availability, a path selection strategy is proposed to determine a physical lightpath of which the vacant spectrum resources can be effectively used. Simulation results show that the RA-CVONE algorithm can significantly shorten the length of the physical lightpaths which are selected to embed virtual optical links, reduce the bandwidth blocking probability of virtual optical network requests, and improve the spectrum utilization of elastic optical networks.

Cross-Layer Optimization of Network Resource Virtualization in IP Over O-OFDM Networks

Optical orthogonal frequency division multiplexing (O-OFDM) is a promising transport technology for virtualization and bandwidth sharing over highcapacity optical fibers. In this paper, we propose an IPover O-OFDM optical network architecture utilizing network virtualization across IP and optical layers. A design goal of this architecture is to provide dynamicity and flexibility in addition to the high capacity required to support multirate traffic with various quality of service requirements. In this architecture, optimized allocation of optical resources to virtual optical networks that accommodate the traffic of IP networks is considered. O-OFDM is utilized to allocate a set of low-rate contiguous subcarriers to each traffic connection represented by a virtual optical link. In addition, we study virtualization of IP network resources (i.e., routers and bandwidth capacities of links) in order to compose several customized virtual IP networks. Furthermore, coordination between IP and optical network virtualization mechanisms is investigated in order to achieve the required optimization of network resource virtualization across the different domains. For this purpose, a novel replanning approach is proposed and is aimed to adapt the resources allocated for virtual optical networks based on the requirements of an IP layer.

Virtual Optical Network Resource Allocation Using PCE Global Concurrent Optimization for Dynamic Deployment of Virtual GMPLS-Controlled WSON

We present dynamic virtual optical network resource allocation (VON RA) algorithms for on-demand deployment of virtual wavelength switched optical networks (WSONs), which is handled by a resource broker with a virtual network topology manager (VNTM). The resource broker with VNTM dynamically configures and deploys independent instances of virtual WSONs over the same physical optical infrastructure and their own independent virtual generalized multiprotocol label switching control plane. The VON RA is computed by a path computation element using global concurrent optimization, which assigns the resources for the virtual optical links (e.g., wavelengths) and nodes. The experimental assessment and performance evaluation have been carried out in the ADRENALINE testbed. We discuss the obtained results on a National Science Foundation Network topology in terms of the VON request blocking rate and VON setup delay, which are used to compare the different proposed algorithms.

Dynamic virtual GMPLS-controlled WSON using a Resource Broker with a VNT Manager on the ADRENALINE testbed

We present a Resource Broker with a Virtual Network Topology Manager (VNTM) which dynamically deploys virtual GMPLS-controlled WSON networks. Virtual Optical links are constructed by grouping established optical connections which are managed by the VNTM. We evaluate the performance of the Resource Broker in the ADRENALINE testbed.