Optical Network Resources Research Articles

A Dynamic Multi-Layer Resource Allocation and Optimization Framework in Application-Centric Networks

In a software-defined networking (SDN) based network, service requests can be accommodated according to the network application requirements. We devise a framework where such requirements drive IP and optical network resource allocation, dynamic optimization, and instantiation through an SDN orchestrator. The framework aims to balance the often-conflicting goals such as energy savings and resource allocation speed, while ensuring that the orchestrator can accommodate incoming service requests without interrupting the running services. We show the functionality of the framework with a simulation on a real network topology and a realistic input traffic.

Burst Stream Resource Reservation Algorithm of Satellite E-OBS Network Based on Preemption Window

An onboard optical burst network resource reservation algorithm named PWBR is proposed for satellite optical switching network. The algorithm uses burst stream as reservation unit and is based on preemption window which can guarantee the QoS of HP burst; network delay performance and packet loss ration are improved through big granularity burst stream. Computer simulations show that the packet loss ratio of HP BDP is lowered 79%, the packet loss ratio of LP BDP is lowered 73% in E-OBS structure than C-OBS when network load is 0.7.and its end-to- end delay is improved 2.1% than RRBS, 3.5% than JET, 7.7% than DRR, 11.5% than JIT.

A Cross-layer Traffic Grooming Algorithm in Joint Optimization of the IP over Elastic Optical Network

Abstract To fully utilize the existing optical network resource, the dynamic traffic grooming technology, which could efficiently multiplex many low-speed services arriving dynamically onto high-capacity optical channels, has been studied extensively and used widely. In this article, the problem of dynamic traffic grooming in joint optimization of IP over elastic optical network (EON) is studied. This problem consists of three sub-problems at two layers: the routing problem at the IP-layer (IPR), the routing, modulation level (RML), and the spectrum allocation (SA) problems at the optical layers. We proposed a novel topology-integration and adaptive-modulation based in cross-layer routing spectrum allocation (CL-RSA) algorithm, which follows a multi-cost approach that solves the IPR, the RML, and the SA problems jointly. The most important features of the proposed algorithm are merging physical topology with virtual topology and using the minimum-weight preferred method for route selection. Meanwhile, the effect of physical-layer impairments (PLI) on signal transmission is considered. In addition, the adaptive modulation scheme is used to allocate the spectrum resource. The simulation results show that the algorithm can effectively improve the spectrum resource utilization and reduce the network blocking probability compared to other algorithms in various network conditions, especially in the high load condition effectively.

Wavelength Allotment for All-to-All Broadcast in WDM Optical Modified Linear Array for Reliable Communication

All-to-all broadcast in a network is to distribute an exclusive message from each node to every other node. It is a vital requirement in high performance computing and communication applications including enterprises operating data centers. It is also a core issue in telecommunication network where each node in the network needs to gather information about all the other nodes for efficient management of network resources. WDM optical networks act as the backbone for telecommunication networks. Wavelengths are precious resources in WDM optical networks and its usage must be limited to reduce network cost and complexity. Optical linear array finds application in LAN, WAN and MAN and its topology needs to be modified to reduce wavelength requirements and hop count. In this paper, a linear array network is modified by additionally joining alternate nodes. For such a modified linear array, the minimum wavelength number needed to support all-to-all broadcast is derived by grouping non overlapping connections on a common wavelength. The results obtained for modified linear array shows that the wavelength number needed is approximately reduced by half when compared with that of a linear array.

Cross stratum resources protection in fog-computing-based radio over fiber networks for 5G services

Abstract In order to meet the requirement of internet of things (IoT) and 5G, the cloud radio access network is a paradigm which converges all base stations computational resources into a cloud baseband unit (BBU) pool, while the distributed radio frequency signals are collected by remote radio head (RRH). A precondition for centralized processing in the BBU pool is an interconnection fronthaul network with high capacity and low delay. However, it has become more complex and frequent in the interaction between RRH and BBU and resource scheduling among BBUs in cloud. Cloud radio over fiber network has been proposed in our previous work already. In order to overcome the complexity and latency, in this paper, we first present a novel cross stratum resources protection (CSRP) architecture in fog-computing-based radio over fiber networks (F-RoFN) for 5G services. Additionally, a cross stratum protection (CSP) scheme considering the network survivability is introduced in the proposed architecture. The CSRP with CSP scheme can effectively pull the remote processing resource locally to implement the cooperative radio resource management, enhance the responsiveness and resilience to the dynamic end-to-end 5G service demands, and globally optimize optical network, wireless and fog resources. The feasibility and efficiency of the proposed architecture with CSP scheme are verified on our software defined networking testbed in terms of service latency, transmission success rate, resource occupation rate and blocking probability.

Network Virtualization in Spectrum Sliced Elastic Optical Path Networks

The recent decade has witnessed an evolution toward virtualization of everything for the IT industry. Resources, from utility resources to networking components and functions, are abstracted as logical or virtual services. Virtualization results in elastic, agile, and automated resource provision, and facilitates the resource pricing in a pay-as-you-go model. Among this wave, the optical community has made parallel efforts in virtualizing resources in optical networks including both optical node and link resources. A virtualized optical network can not only seamlessly support automated resource provision, but also supply high-bandwidth any-to-any connectivity for network virtualization. In this paper, we overview the motivations and architecture for optical-based network virtualization. Among candidate optical networking paradigms, we argue that spectrum-sliced elastic optical path (SLICE) networks can be considered as a promising substrate choice, and study the key enabling problem, namely optical virtual network embedding over SLICE networks (OVNE-SLICE). We prove the NP-completeness of the OVNE-SLICE problem, and propose two mathematical models for this problem based on a concept named path-channel . The models are evaluated in our simulation, and compared with alternative models proposed in the literature.

Shared path protection through reconstructing sharable bandwidth based on spectrum segmentation for elastic optical networks

Abstract In order to address the problems of spectrum fragmentation and low sharing degree of spectrum resources in survivable elastic optical networks, an improved algorithm, called shared path protection by reconstructing sharable bandwidth based on spectrum segmentation (SPP-RSB-SS), is proposed in the paper. In the SPP-RSB-SS algorithm, for reducing the number of spectrum fragmentations and improving the success rate of spectrum allocation, the whole spectrum resource is partitioned into several spectrum segments. And each spectrum segment is allocated to the requests with the same bandwidth requirement in priority. Meanwhile, the protection path with higher spectrum sharing degree is selected through optimizing the link cost function and reconstructing sharable bandwidth. Hence, the protection path can maximize the sharable spectrum usage among multiple protection paths. The simulation results indicate that the SPP-RSB-SS algorithm can increase the sharing degree of protection spectrum effectively. Furthermore, the SPP-RSB-SS algorithm can enhance the spectrum utilization, and reduce the bandwidth blocking probability significantly.

Performance evaluation of software-defined clustered-optical access networking for ubiquitous data center optical interconnection

Ubiquitous data center optical interconnection between user and data center has become a promising scenario gradually to accommodate high-performance services with end-to-end quality guaranteed. In our previous work, we implemented to provision data center application in inter-data center optical interconnection. In view of this, this study extends to consider the networking relationship between user and data center. We propose a novel software-defined clustered-optical access networking (SD-COAN) architecture for data center services in ubiquitous data center optical interconnection. A cross-stratum flow schedule (CSFS) strategy is introduced for SD-COAN based on the proposed architecture. The SD-COAN can enhance the responsiveness to the dynamic end-to-end data center demands and globally optimize optical access network and application resources effectively. The overall feasibility and efficiency of the proposed architecture are experimentally verified on our OpenFlow-based enhanced SDN testbed. The performance of CSFS strategy under heavy traffic load scenario is also quantitatively evaluated based on SD-COAN architecture in terms of resource occupation rate, average throughput and average provisioning delay, compared with other provisioning strategy.

Virtual Network Reconfiguration in Elastic Optical Path Networks for Future Bandwidth Allocation

Given the limited number of resources (i.e., frequency slots and transponders at optical switches) in elastic optical networks, one approach to accommodating traffic demand is for the network operator to offer a certain number of leased lightpaths in response to requests from service providers, while configuring a virtual network (VN) that accommodates the traffic demands of other consumers. It is essential to reconfigure the VN according to changes in traffic while setting aside resources for leased lightpaths and accommodating increased traffic demand on the VN. Our research group has proposed a VN reconfiguration method for traditional wavelength division multiplexing networks based on attractor selection, which is a model of the behavior by which living organisms adapt to unknown changes in their surrounding environment. However, simply adopting this method cannot make the best use of elastic optical networks since it assigns all wavelengths to accommodate the current traffic demand, which leads to a lack of resources for accommodating the future traffic demand. In this paper, we therefore propose a method for reconfiguring a VN over an elastic optical network. To set aside resources for future traffic demands, we newly define the potential bandwidth as a metric that reflects the bandwidth that can be additionally offered. Our method reconfigures a VN based on attractor selection using information about the service quality on the VN and the potential bandwidth, and it also adjusts the bandwidths of all the lightpaths that form the VN. The evaluation results show that our method can reconfigure a VN so the service quality on the VN is improved while keeping some resources unused.

Experimental demonstration of multi-dimensional resources integration for service provisioning in cloud radio over fiber network.

Cloud radio access network (C-RAN) becomes a promising scenario to accommodate high-performance services with ubiquitous user coverage and real-time cloud computing in 5G area. However, the radio network, optical network and processing unit cloud have been decoupled from each other, so that their resources are controlled independently. Traditional architecture cannot implement the resource optimization and scheduling for the high-level service guarantee due to the communication obstacle among them with the growing number of mobile internet users. In this paper, we report a study on multi-dimensional resources integration (MDRI) for service provisioning in cloud radio over fiber network (C-RoFN). A resources integrated provisioning (RIP) scheme using an auxiliary graph is introduced based on the proposed architecture. The MDRI can enhance the responsiveness to dynamic end-to-end user demands and globally optimize radio frequency, optical network and processing resources effectively to maximize radio coverage. The feasibility of the proposed architecture is experimentally verified on OpenFlow-based enhanced SDN testbed. The performance of RIP scheme under heavy traffic load scenario is also quantitatively evaluated to demonstrate the efficiency of the proposal based on MDRI architecture in terms of resource utilization, path blocking probability, network cost and path provisioning latency, compared with other provisioning schemes.

OpenFlow-based adaptive adjustment of optical path resources in dynamic optical networks

The development of broadband services gives the existing networks a tremendous pressure. It forces us to think about what measures to take, in addition to increasing the capacity, to improve the service capabilities of the networks and reduce the costs. The virtual programmable features of OpenFlow bring a lot of flexibility and convenience to the operation of networks. For the purpose of applying the programmable feature of software to future optical networks, this paper proposes a novel OpenFlow-based adaptive adjustment scheme for optical path resources. In addition, to control the underlying devices, the current standard OpenFlow protocol is extended, and four new message types are developed to communicate between OpenFlow controller and OpenFlow virtual switch (OVS). An experiment of OpenFlow-based adaptive spectrum adjustment is carried out on the experimental test-bed that we proposed to verify the feasibility of the above scheme. The experimental results demonstrate that the software control on optical connections is an effective solution to the adaptive adjustment of optical path resources in dynamic optical networks.

Performance evaluation of multi-stratum resources optimization with network functions virtualization for cloud-based radio over optical fiber networks

Cloud radio access network (C-RAN) has become a promising scenario to accommodate high-performance services with ubiquitous user coverage and real-time cloud computing using cloud BBUs. In our previous work, we implemented cross stratum optimization of optical network and application stratums resources that allows to accommodate the services in optical networks. In view of this, this study extends to consider the multiple dimensional resources optimization of radio, optical and BBU processing in 5G age. We propose a novel multi-stratum resources optimization (MSRO) architecture with network functions virtualization for cloud-based radio over optical fiber networks (C-RoFN) using software defined control. A global evaluation scheme (GES) for MSRO in C-RoFN is introduced based on the proposed architecture. The MSRO can enhance the responsiveness to dynamic end-to-end user demands and globally optimize radio frequency, optical and BBU resources effectively to maximize radio coverage. The efficiency and feasibility of the proposed architecture are experimentally demonstrated on OpenFlow-based enhanced SDN testbed. The performance of GES under heavy traffic load scenario is also quantitatively evaluated based on MSRO architecture in terms of resource occupation rate and path provisioning latency, compared with other provisioning scheme.

Demand-Aware Network Function Placement

Network function virtualization is an emerging network resource utilization approach which decouples network functions from proprietary hardware and enables adaptive services to end-user requests. To accommodate the network function requests, network function instances are created and deployed at runtime. In this paper, we study a network virtualization scheme to orchestrate and manage networking and network function services. We propose an integrated design for network function instance allocation and end-to-end demand realization sharing the same physical substrate network and demonstrate that the corresponding network design problem is NP complete. A mixed-integer programming formulation is proposed first to find its optimal solution, followed by a two-player pure-strategy game model which captures the competition on physical resources between network function instance allocation and routing. We then design an algorithm based on iterative weakly dominated elimination in Game Theory. Computational results demonstrate the value of the integrated approach and its ability to allocate network function instances supporting end-to-end requests with limited physical resources in optical networks.

Power-aware virtual optical network provisioning in flexible bandwidth optical networks [Invited

Considering the virtual network infrastructure as a service, optical network virtualization can facilitate the physical infrastructure sharing among different clients and applications that require optical network resources. Obviously, mapping multiple virtual network infrastructures onto the same physical network infrastructure is one of the greatest challenges related to optical network virtualization in flexible bandwidth optical networks. In order to efficiently address the virtual optical network (VON) provisioning problem, we can first obtain the virtual links' order and the virtual nodes' order based on their characteristics, such as the bandwidth requirement on virtual links and computing resources on virtual nodes. We then preconfigure the primary and backup paths for all node-pairs in the physical optical network, and the auxiliary graph is constructed by preconfiguring primary and backup paths. Two VON mapping approaches that include the power-aware virtual-links mapping (PVLM) approach and the power-aware virtual-nodes mapping (PVNM) approach are developed to reduce power consumption for a given set of VONs in flexible bandwidth optical networks with the distributed data centers. Simulation results show that our proposed PVLM approach can greatly reduce power consumption and save spectrum resources compared to the PVNM approach for the single-line rate and the mixed-line rate in flexible bandwidth optical networks with the distributed data centers.

SUDOI: software defined networking for ubiquitous data center optical interconnection

Ubiquitous data center optical interconnection is a promising scenario to meet the high burstiness and high-bandwidth requirements of services in terms of the user-access-oriented interconnection between user and data center, inter-data- center, and intra-data-center interconnection. However, in the current mode of operation, the control of the data center and optical network is separately deployed. Enabling even limited interworking among these separated control systems does not provide a mechanism to exchange resource information and enhance the high-level performance requirement of applications. Our previous work implemented cross-stratum optimization of optical network and application strata resources inter-data-center, which allows the accommodation of data center services. In view of this, this study extends to the ubiquitous data center optical interconnection scenario. This article presents a novel SUDOI architecture aimed at extensive user access from the perspective of heterogeneous cross-stratum and multi-layer networking modes. SUDOI can enable cross-stratum optimization of application and optical network stratum resources, and enhance multiple- layer resource integration in the ubiquitous data center optical interconnection. The functional modules of SUDOI architecture, including the core elements of various controllers, are described in detail. The cooperation procedure in user-access-oriented interconnection, multiple- layer resource integration inter-data-center, and intra-data-center service modes is investigated. The feasibility and efficiency of the proposed architecture are also experimentally demonstrated on our OaaS testbed with OpenFlow-enabled optical nodes, and compared to the CSO scheme in terms of blocking probability and resource occupation rate. Numerical results are given and analyzed based on the testbed. Some future discussion and exploration issues are presented in the conclusion.

Continuity Aware Spectrum Allocation Schemes for Virtual Optical Network Embedding in Elastic Optical Networks

Abstract Optical network virtualization has been studied as a promising technique for optical network resources provisioning. In the virtualization context of Elastic Optical Network (EON), Virtual Optical Network Embedding (VONE) is investigated as a key issue for allocating spectrum resources to VON requests. This paper discusses the continuity constraint for the VONE problem in EONs, and presents three continuity-aware spectrum allocation schemes according to strict and relaxed continuity constraints. We have demonstrated the proposed schemes on emulated testbed to verify the feasibility of composing VON with discontiguous spectrum resources. Additionally, the performances of the proposed schemes are compared via simulation in terms of blocking probability, spectrum resource utilization and discontinuity degree.

ESTIMATION OF OPTICAL ACCESS NETWORK BANDWIDTH DEMAND USING MONTE CARLO SIMULATION

Continuous forecast of bandwidth demand in order to achieve a proper network planning and dimensioning is one of the key challenges that network operators need to deal with. The importance of this issue is highlighted with the necessity of proper decision making regarding capital investments and the permanent increase in traffic volume. Under-investing in network resources lead to low network performances and hence dissatisfied customers, while over-investing may cause over-dimensioned capacities which leads to lower resource utilization and opportunity losses. In that perspective, it is essential to determine whether current network capacities satisfy bandwidth requirements. If it does, determining relevant time period is of great significance. As the bandwidth demand increases by the development of new services, the existing broadband networks need to be upgraded. The growing bottleneck can be solved rolling out optical access network. These networks are characterized by greater bandwidth supply enhancement compared to bandwidth demand. That fact emphasizes the need of appropriate bandwidth forecast. This paper presents model for optical access networks future bandwidth demand and network resource utilisation estimation. In order to appropriately address valid demand of all households in a given area, Monte Carlo simulation is applied.

Performance evaluation of multi-stratum resources integration based on network function virtualization in software defined elastic data center optical interconnect.

Data center interconnect with elastic optical network is a promising scenario to meet the high burstiness and high-bandwidth requirements of data center services. In our previous work, we implemented multi-stratum resilience between IP and elastic optical networks that allows to accommodate data center services. In view of this, this study extends to consider the resource integration by breaking the limit of network device, which can enhance the resource utilization. We propose a novel multi-stratum resources integration (MSRI) architecture based on network function virtualization in software defined elastic data center optical interconnect. A resource integrated mapping (RIM) scheme for MSRI is introduced in the proposed architecture. The MSRI can accommodate the data center services with resources integration when the single function or resource is relatively scarce to provision the services, and enhance globally integrated optimization of optical network and application resources. The overall feasibility and efficiency of the proposed architecture are experimentally verified on the control plane of OpenFlow-based enhanced software defined networking (eSDN) testbed. The performance of RIM scheme under heavy traffic load scenario is also quantitatively evaluated based on MSRI architecture in terms of path blocking probability, provisioning latency and resource utilization, compared with other provisioning schemes.

Cross-layer restoration with software defined networking based on IP over optical transport networks

The IP over optical transport network is a very promising networking architecture applied to the interconnection of geographically distributed data centers due to the performance guarantee of low delay, huge bandwidth and high reliability at a low cost. It can enable efficient resource utilization and support heterogeneous bandwidth demands in highly-available, cost-effective and energy-effective manner. In case of cross-layer link failure, to ensure a high-level quality of service (QoS) for user request after the failure becomes a research focus. In this paper, we propose a novel cross-layer restoration scheme for data center services with software defined networking based on IP over optical network. The cross-layer restoration scheme can enable joint optimization of IP network and optical network resources, and enhance the data center service restoration responsiveness to the dynamic end-to-end service demands. We quantitatively evaluate the feasibility and performances through the simulation under heavy traffic load scenario in terms of path blocking probability and path restoration latency. Numeric results show that the cross-layer restoration scheme improves the recovery success rate and minimizes the overall recovery time.

Performance evaluation of data center service localization based on virtual resource migration in software defined elastic optical network.

Data center interconnection with elastic optical network is a promising scenario to meet the high burstiness and high-bandwidth requirements of data center services. In our previous work, we implemented cross stratum optimization of optical network and application stratums resources that allows to accommodate data center services. In view of this, this study extends the data center resources to user side to enhance the end-to-end quality of service. We propose a novel data center service localization (DCSL) architecture based on virtual resource migration in software defined elastic data center optical network. A migration evaluation scheme (MES) is introduced for DCSL based on the proposed architecture. The DCSL can enhance the responsiveness to the dynamic end-to-end data center demands, and effectively reduce the blocking probability to globally optimize optical network and application resources. The overall feasibility and efficiency of the proposed architecture are experimentally verified on the control plane of our OpenFlow-based enhanced SDN testbed. The performance of MES scheme under heavy traffic load scenario is also quantitatively evaluated based on DCSL architecture in terms of path blocking probability, provisioning latency and resource utilization, compared with other provisioning scheme.