Greenfield Deployment Research Articles

Managing cloud-native applications using vSphere with Tanzu and Tanzu Kubernetes grid

This study examines VMware cloud-native platforms, emphasizing their orchestration and automated management functionalities for container technologies, which are essential in modern IT infrastructure. The study seeks to comprehensively examine VMware Tanzu's architecture, technical elements, and efficacy in facilitating containerized applications. Case studies were used to gain comprehensive insights into brownfield and greenfield deployment strategies, illustrating practical implementation challenges and advantages for vSphere with Tanzu and Tanzu Kubernetes Grid. These studies emphasize scenarios from gradually incorporating Kubernetes into current VMware environments to developing optimized infrastructures from the ground up. Significant findings encompass strategies for scalable IT infrastructure, innovative applications of persistent storage via VMware Cloud Native Storage, and the function of Tanzu Kubernetes Grid in multi-cloud deployment contexts. The study concludes that Tanzu platforms successfully integrate traditional virtualization with contemporary containerization, providing robust scalability, flexibility, and efficient resource-use solutions. The practical implications emphasize how organizations can utilize these insights to seamlessly integrate Kubernetes workloads, optimize investments in VMware ecosystems, and respond to evolving IT requirements.

PRODIGY+: a robust progressive upgrade approach for elastic optical networks

Elastic optical networks (EONs) operating in the C-band have been widely deployed worldwide. However, two major technologies—multiband elastic optical networks (MB-EONs) and space division multiplexed elastic optical networks (SDM-EONs)—can significantly increase network capacity beyond traditional EONs. A one-time greenfield deployment of these flexible-grid technologies may not be practical, as existing investments in flexible-grid EONs need to be preserved and ongoing services must face minimal disruption. Therefore, we envision the coexistence of flexible-grid, multiband, and multicore technologies during the brownfield migration. Each technology represents a tradeoff between higher capacity and greater deployment overhead, directly impacting network performance. Moreover, as traffic demands continue rising, capacity exhaustion becomes inevitable. Considering the different characteristics of these technologies, we propose a robust network planning solution called Progressive Optics Deployment and Integration for Growing Yields (PRODIGY+) to gradually migrate current C-band EONs. PRODIGY+ employs proactive measures inspired by the Swiss Cheese Model, making the network robust to traffic peaks while meeting service level agreements. The upgrade strategy enables a gradual transition to minimize migration costs while continuously supporting increasing traffic demands. We provide a detailed comparison of our proposed PRODIGY+ strategy against baseline strategies, demonstrating its superior performance.

Brown-Field Migration Aware Routing and Spectrum Assignment in Backbone Optical Networks

With the development of optical networks technology, broad attention has been paid to flexible grid technology in optical networks due to its ability to carry large-capacity information as well as provide flexible and fine-grained services through on-demand spectrum resource allocation. However, a one-time green-field deployment of a flexible grid network may not be practical. The transition technology called the fixed/flex-grid optical networks is more applicable and highly pragmatic. In such network, many nodes would likely be upgraded from a fixed-grid to flex-grid. In fact, dynamic service provisioning during the process of a node upgrade in fixed/flex-grid optical networks have become a challenge because the service connection can be easily interrupted, which leads to considerable data loss because of node upgrade. To overcome this challenge, we propose a brown-field migration aware routing and spectrum assignment (BMA-RSA) algorithm in fixed/flex-grid optical networks. The aim is to construct a probabilistic migration label (PML) model. The well-designed label setting of PML can balance the relationship between distance and node-upgrade probability. Dynamic service provisioning operations are undertaken based on the PML model to achieve a migration-aware dynamic connection before network migration occurs. We also evaluate the performance of different service provisioning strategies under different traffic models. The simulation results show that the BMA-RSA algorithm can achieve: (1) the tradeoff between distance and node upgrade probability during the process of service provisioning; (2) lower service interruption compared with the traditional non-migration aware K-shortest-path routing and spectrum assignment algorithm.

Dynamic routing, spectrum, and modulation-format allocation in mixed-grid optical networks

Traffic in optical backbone networks is evolving rapidly in terms of type, volume, and dynamicity following the rapid growth of cloud-based services, ongoing adoption of 5G communications, and explosion of the Internet of Things (IoT). The elastic optical network (EON), by adopting a flexible grid, can provide the required capacity and flexibility to handle these rapid changes. However, operators rarely perform greenfield deployments, so to limit upfront investment, a gradual migration from fixed-grid to flexible-grid switching equipment is preferable. For gradual migration, switching nodes can be upgraded (starting from bottleneck network links) while keeping the rest of the traditional fixed-grid network operational. We refer to the coexistence of fixed-grid and flex-grid optical equipment as a “mixed-grid” network. Traditional algorithms for dynamic resource assignment in EONs will not effectively be applicable in a mixed-grid network due to interoperability issues among fixed- and flex-grid nodes. In this study, we propose a new algorithm, called Mixed-grid-aware Dynamic Resource Allocation, to solve the route, spectrum, and modulation-format allocation problem in a mixed-grid network while considering interoperability constraints. Our numerical results (on representative network topologies) show that the proposed method achieves 50% less blocking (for 50% offered load) compared to the traditional approach.

Total Cost of Ownership of Digital vs. Analog Radio-Over-Fiber Architectures for 5G Fronthauling

The article analyzes the total cost of ownership (TCO) of 5G fronthauling solutions based on analog and digital radio-over-fiber (RoF) architectures in cloud radio access networks (C-RANs). The capital and operational expenditures (CAPEX, OPEX) are assessed, for a 10-year period, considering three different RoF techniques: intermediate frequency analog RoF (IF-A-RoF), digital signal processing (DSP) assisted analog RoF (DSP-A-RoF), and digital RoF (D-RoF) based on the common public radio interface (CPRI) specifications. The greenfield deployment scenario under exam includes both fiber trenching (FT) and fiber leasing (FL) options. The TCO is assessed while varying (i) the number of aggregated subcarriers, (ii) the number of three-sector antennas located at the base station, and (iii) the mean fiber-hop length. The comparison highlights the significance that subcarrier aggregation has on the cost efficiency of the analog RoF solutions. In addition, the analysis details the contribution of each cost category to the overall CAPEX and OPEX values. The obtained results indicate that subcarrier aggregation via DSP results in high cost efficiency for a mobile fronthaul network, while a CPRI-based architecture together with FL brings the highest OPEX value.

Enhancing the Survivability and Power Savings of 5G Transport Networks Based on DWDM Rings

So much has been promised by the fifth generation (5G), the revolution of mobile communications that allows for flexible, speedy, and efficient delivery of unlimited data and information sharing between people located anywhere and at any time. The road toward making 5G a reality, however, requires concerted efforts in designing both the underlying infrastructure and the enabling technologies to simultaneously satisfy not only capacity but also reliability, low latency, synchronization, security, and energy consumption requirements. In that respect, the transport segment of a 5G network, i.e., the backhaul network of mobile base stations (BSs) or fronthaul of remote radio units (RRUs), must not be overlooked. Further, any future design of a resilient 5G transport network must also consider the potential exploitation of switching on and off network resources such as RRUs and BSs to improve energy efficiency. At present, there are few inroads on 5G transport networks that provide resilience during sleep mode operation. Therefore, the focus of this work is aimed specifically at providing solutions to enhance both the survivability and power savings of mobile transport networks that implement sleep mode operation. We develop our solutions around a dense wavelength-division multiplexed (DWDM) optical ring transport network that has been previously proven to be energy efficient as a 5G transport network. Further, we propose two survivable schemes that exploit the inherent resiliency of the ring network. In conjunction with cw monitoring signals and highly sensitive monitoring modules, these schemes facilitate for the first time continuous monitoring of the network at all times, even during idle periods of transmission when transceivers are sleeping. That is, our proposed schemes enable network energy savings through sleep mode operation without having to compromise on failure detection time. Compared to a conventional ring architecture, our survivable schemes provide enhanced connection availability and power savings at less than 0.2% incremental network cost. Based on performance evaluations for brownfield, duct reuse, and greenfield deployments, we provide guidance on the most suitable scheme for each considered scenario, thus driving the future choices of mobile network operators.

Designing a green optical network unit using ARMA-based traffic prediction for quality of service-aware traffic

The optical access networks (OANs) provide an attractive solution to the bandwidth bottleneck problem of the last mile. However, it has been proved (Baliga et al. in J Lightwave Technol 27(13):2391---2403, 2009; Baliga et al. in IEEE Commun Mag 49(6):70---77, 2011) that the OAN consumes a significant ratio of the total energy consumed in an optical networking scenario. This has provided incentive for inspection of energy-efficient schemes for OANs. It has been demonstrated in the literature that energy consumption figures of an OAN can be improved by either designing efficient hardware or employing better media access control (MAC) protocols. In this paper, we design a MAC protocol for OANs to ensure energy-efficiency in the presence of quality of service (QoS)-aware traffic. The proposed scheme incorporates traffic prediction-based selection of different sleep (energy-efficient) modes of operation, of the optical network units--ONUs (OAN end units). It also implements switching between different sleep modes to maintain high QoS with significant energy-efficiency figures. The discussed scheme requires processing at the ONU only and can work independent of the entire OAN (ONU assisted). Thus, our proposal is an attractive solution for the already deployed networks or even in green field deployment.

Cost assessment of FTTdp networks with G.fast

FTTdp networks using G.fast can complement the rollout of FTTH, especially in regions where the deployment of fiber inside the building is difficult. This article analyzes the main cost components of FTTdp networks with G.fast and the cost differences that can be achieved in comparison to FTTH networks. The two metrics employed in the article, the cost per home passed and the cost per home connected, were applied to six different geotypes that range from dense urban to rural scenarios. The results show that the cost per home passed of an FTTdp network with the distribution point located in the street is lower than the cost of FTTH. The cost per home connected for FTTdp is lower than that of FTTH for all of the scenarios studied. The cost reduction rates achieved by FTTdp networks are higher when employing a brownfield deployment scheme than when employing a greenfield deployment scheme.

Design and dimensioning of hybrid PONs

We investigate the greenfield deployment of hybrid time division multiplexing/wavelength division multiplexing passive optical networks, i.e., the optimized covering of a given geographical area by a set of cost-effective and properly dimensioned hybrid PONs. We first propose a three-phase optimization scheme. In the first phase, a p-center model is proposed to determine the best ONU clusterings and the lower-level passive distribution node equipment locations. The second phase takes care of the placement of the upper-level passive distribution node equipment and the third one, using the traffic demands, a mix of unicast and multicast requests, selects the most appropriate passive distribution node equipment, i.e., either an arrayed waveguide gratings or a splitter. We next merge the first two phases, leading then to a two-phase scheme. Computational experiments are conducted on two sets of ONUs, one with 128 and one with 512 ONUs. We compare the two- and three-phase schemes in terms of PON design costs. We observe that the two-phase scheme provides more cost-effective solutions. We also provide a sensitivity analysis with respect to several parameters in order to identify the number of ONU clusters that minimizes the deployment cost.

Migration from fixed grid to flexible grid in optical networks

Optical WDM backbone networks based on fixed spectrum grid have limitations such as low spectrum utilization and rigidity in provisioning for heterogeneous rates. Flexible-grid technologies can alleviate these limitations for on-demand provisioning. These technologies represent promising candidates for future optical networks supporting beyond-100-Gb/s signals. However, a one-time green-field deployment of flexible-grid technologies may not be practical, as the already-made investment in existing fixed-grid WDM networks needs to be preserved, and interruptions to ongoing services need to be minimized. Therefore, we envision that fixed-and flexible-grid technologies will coexist, which will bring the challenge of interoperating fixed-and flexible-grid equipment. It is also important to design the optimum migration strategy to maximize cost effectiveness and minimize service interruption. In this article, we discuss the key aspects of network architectures supporting coexistence of fixed and flexible grid technologies, and outline the challenges of network operations. We also propose and evaluate different migration strategies from fixed grid to flexible grid under different network scenarios.

Characterization and optimization of the power consumption in wireless access networks by taking daily traffic variations into account

In this study, a power consumption model as a function of the traffic is developed for macrocell base stations based on measurements on an actual base station. This model allows us to develop energy-efficient wireless access networks by combining the Green radio access network design (GRAND) tool designed by the authors, which develops an always-on network with a minimal power consumption for a predefined area, and an algorithm that introduces power reducing techniques in the network such as sleep modes and cell zooming. Green-field deployments and optimization of existing networks are investigated. For a green-field deployment, it was found that introducing sleep modes and cell zooming in the network can reduce the power consumption by up to 14.4% compared to the network without sleep modes and cell zooming. Optimizing existing networks by applying GRAND (without sleep modes and cell zooming) results in a power consumption reduction of 34.5% compared to the original network. A careful selection of base station locations already results in a significant energy saving. Introducing sleep modes and cell zooming to the current networks results in a saving of 8%. Sleep modes and cell zooming are promising energy-saving techniques for future wireless networks.

Technology innovations and architecture solutions for the next-generation optical access network

Although deployment of fiber to the home (FTTH) systems has been ongoing for over 5 years in certain markets, the industry is still in the early phases of what is expected to be a decades-long optical fiber–based access network build-out. Deployment so far has been largely opportunistic, as in greenfield deployment or copper rehab; competitive, as competitive local exchange carriers (CLECs), utilities, and small multiple systems operators (MSOs) roll out solutions; policy-driven, at the national or municipal level; and strategic, in some isolated cases of a few large carriers. In the coming years as the appetite for bandwidth continues to grow, fiber-based networks will become the only acceptable solution. FTTH technologies have already undergone several stages of evolution, from asynchronous transfer mode passive optical network (APON) to broadband PON (BPON), Ethernet PON (EPON), and Gigabit PON (GPON)—and they will continue to do so in the future. Continuous innovations will allow for a long term increase in bandwidth, an improved cost structure, and greater reach. Starting from current FTTH architectures, including PON, point-to-point (PP), active Ethernet (AE), this paper will focus on the next-generation architectures and supporting technologies that will be used in the future including 10 Gbps PON (10GPON), multi-lambda GPON, coarse wavelength division multiplexing (CWDM) PON, and dense WDM (DWDM)-PON. It will show the relative merits of each architecture, the required supporting technologies, and the role of these solutions in the long term evolution of access networks.