Quasi-Dynamic Network Design Considering Different Service Holding Times

We propose a network segmentation and design algorithm based on traffic distribution information. Numerical experiments demonstrated that the proposed algorithm can greatly reduce network cost.

This paper explores the technologies that will enable a further leap forward in transport network evolution. First, requirements of the future transport network are elucidated. Existing network cost is evaluated and the viable means to reduce transport network cost are identified. It is demonstrated that optical path technologies such as WP (wavelength path) and VWP (virtual wavelength path) will play a key role in this. They enhance not only transmission capacity but also cross‐connect node throughput cost‐effectively by capitalizing on the wavelength routeing scheme. Optical path realization technologies focusing on optical path cross‐connect systems are examined. Requirements for the optical path cross‐connect system are then elucidated, and a new cross‐connect system architecture is evaluated. The architecture exploits PLC (planar lightwave circuit) and other commercially available technologies suitable for large‐scale production. The evaluations include cross‐connect node upgradability, modular growth capability, total node cost, optical loss and switching power consumption. It is proved that the architecture has significant advantages over existing switch architectures. The optical path technologies provided in this paper will pave the way for a new transport network paradigm, a ubiquitous, bandwidth‐abundant and affordable broadband ISDN.

The North-East Corridor (NEC) Testbed project is the 3rd of three NIST (National Institute of Standards and Technology) greenhouse gas emissions testbeds designed to advance greenhouse gas measurements capabilities. A design approach for a dense observing network combined with atmospheric inversion methodologies is described. The Advanced Research Weather Research and Forecasting Model with the Stochastic Time-Inverted Lagrangian Transport model were used to derive the sensitivity of hypothetical observations to surface greenhouse gas emissions (footprints). Unlike other network design algorithms, an iterative selection algorithm, based on a k-means clustering method, was applied to minimize the similarities between the temporal response of each site and maximize sensitivity to the urban emissions contribution. Once a network was selected, a synthetic inversion Bayesian Kalman filter was used to evaluate observing system performance. We present the performances of various measurement network configurations consisting of differing numbers of towers and tower locations. Results show that an overly spatially compact network has decreased spatial coverage, as the spatial information added per site is then suboptimal as to cover the largest possible area, whilst networks dispersed too broadly lose capabilities of constraining flux uncertainties. In addition, we explore the possibility of using a very high density network of lower cost and performance sensors characterized by larger uncertainties and temporal drift. Analysis convergence is faster with a large number of observing locations, reducing the response time of the filter. Larger uncertainties in the observations implies lower values of uncertainty reduction. On the other hand, the drift is a bias in nature, which is added to the observations and, therefore, biasing the retrieved fluxes.

We focus on the design of the logical layer on an optical infrastructure for three different architectures: fixed grid WDM with fixed-rate multilevel modulation (WDM-FRMF), fixed grid WDM with time-domain hybrid modulation formats (WDM-TDHFM) and flexible grid (FG). A fairly detailed physical layer modeling is considered in the network design algorithms. Simulations are performed on a 20 nodes network with varying traffic loads. Besides comparing the two paradigms of flexible and fixed grid networks, including both pure and hybrid modulation formats, in terms of their spectral efficiency and number of blocked requests, we show the importance of integrating a detailed physical layer modeling in the network design phase. We mostly focus on the investigation of the impact of changing physical layer design parameters such as fiber type and span length on network level performance.

The authors describe the preliminary results of a rule-based and hypertext system developed to aid the telecommunication analyst to more advantageously use MIND-Data in network design and cost analysis processes. The software package MIND-Data is an interactive tool designed to help network designers experiment with different alternatives to achieve the best compromise between time-response requirements and network cost. The objectives pursued in the present work include providing intelligent online help support for the MIND-Data user evaluating the general requirements for the network, and providing critic cost analysis for specific parts of the network. >

In the future photonic network, network applications such as grid computing and wide-area distributed SANs (storage area networks) will be realized on a new network platform called the “optical grid.” In this paper, an optical grid is studied, which would provide a network platform to networked applications such as grid computings in the future photonic network. The optical code (OC) label, an identifier for data flow, is an enabler due to its ultrafast processing capability. First, the variable-capacity OC-labeled path and optical code division multiplexed (OCDM) path are studied, which allow one to simultaneously set up a number of connections on a single wavelength path. Next, optical path setup using OC-labeled control packet, which bears the signaling message, is presented and experimentally demonstrated. This enables one to ultimately reduce the overhead time of the optical path setup. © 2005 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 88(12): 1–10, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20241

Compact and efficient sources of high power ultrafast optical pulses are needed to incorporate high speed optical information processing techniques into future photonic networks. In this paper, the robust timing stability associated with optical mode-locked pulse trains from semiconductor diode lasers is examined as an alternative to standard methods of providing synchronous timing signals in future photonic networks. Here, it is demonstrated how these sources may play a role in several photonic network scenarios, such as optical clock distribution, photonic network synchronization, and all optical clock recovery.

This paper presents a novel “virtual fiber” network service that exploits wavebands. This service provides virtual direct tunnels that directly convey wavelength paths to connect customer facilities. To improve the resource utilization efficiency of the service, a network design algorithm is developed that can allow intermediate path grooming at limited nodes and can determine the best node location. Numerical experiments demonstrate the effectiveness of the proposed service architecture.

A Mesh Network Topological Optimization and Routing II (MENTOR-II) algorithm is a low complexity and efficient network design algorithm for IP networks with OSPF routing protocol in which appropriate link weights are assigned to the installed links such that the traffic always routes on the path with minimum distance. However, it should be noted that the flow delay of traffic assigned by MENTOR-II are not controlled because MENTOR-II gives the link weights for only assigning traffic flow into the worthy path, therefore routing of traffic flow does not get together with the traffic engineering. This study proposed a new modified version of MENTOR called Q-MENTOR which is able to assign traffic under flow delay controlled. The Q-MENTOR are evaluated in terms of installation cost, routing cost and reliability for 486 network design conditions. The design results are compared with MENTOR-II and it was found that Q-MENTOR is suitable for designing high maximum utilization networks with good delay and reliability. The results also show that low traffic flow delay requirements often present the worst installation cost, routing cost and reliability.

This paper studies efficient algorithms for dynamic curing policies and the corresponding network design problems to guarantee the fast extinction of epidemic spread in a susceptible-infected-susceptible (SIS) model. We consider a Markov process-based SIS epidemic model. We provide a computationally efficient curing algorithm based on the curing policy proposed by Drakopoulos, Ozdaglar, and Tsitsiklis (2014). Since the corresponding optimization problem is NP-hard, finding optimal policies is intractable for large graphs. We provide approximation guarantees on the curing budget of the proposed dynamic curing algorithm. We also present a curing algorithm fair to demographic groups. When the total infection rate is high, the original curing policy includes a waiting period in which no measurements are taken to mitigate the spread until the rate slows down. By utilizing network design strategies that either delete edges or reduce their weights, we limit the total infection rate, allowing the curing process to proceed continuously without requiring a waiting period. We provide algorithms with provable guarantees for the considered network design problems. In summary, the proposed curing and network design algorithms together provide an effective and computationally efficient approach that mitigates SIS epidemic spread in networks.

A typical operating environment of a packet switching (store-and-forward) computer communication network is that it is shared by many users with different classes of packets. Packets may be classified in a very general fashion by types of users, messages, applications, transactions, response time requirements, packet parameters such as packet rate and length, and by network parameters such as source-destination and path length. A well-designed network must provide access and performance assurance to all packet classes. This paper presents a heuristic algorithm for designing such a communication network. The algorithm presented contains heuristic algorithms for discrete link capacity assignment, priority assignment, and flow assignment problems with an additional feature which allows one to alter network topology interactively. Sample results from applications of the overall network design are also given.

In this paper we provide analytical insights for dimensioning a multi-layer network and in particular the virtual optical transport network topology exported to the packet client layer according to cost and power consumption. A new approach is described, approximating optimum routing, that can be effectively used to provide an estimation of network cost and reference architectures in network implementations. Results using this estimation approach are compared with those obtained using other estimation approaches regarding bandwidth allocation and network costs. We found that the approximated routing calculations, applied on a virtual network topology, do not significantly penalize the accuracy of the results. This approach can be extended to analyze the impact of new a optical networking technique, flexible-grid wavelength division multiplexing (WDM), providing some insights regarding scenarios in which migration from fixed-grid WDM systems to flexible-grid WDM systems would be advantageous in terms of capital cost and power consumption.

Creating resilient and multi-layered transportation networks is of paramount importance for modern society, particularly considering the need to respond to a diverse array of risks. These resilient multilayer transport networks appear to share comparable properties with vital multilayer distribution systems found onboard large and complex ships. However, little is currently known regarding the similarities and differences in the design of multilayer networks found in various contexts, such as transportation infrastructure and shipboard distribution systems. This study introduces several multi-modal networks and elucidates their similarities and differences and their design processes. A case study details a typical topology of integrated onboard distribution systems, represented abstractly as a multilayer network to showcase said similarities and differences. The study concludes with the lessons learned from comparing transportation networks with vital onboard distribution systems and provides an outlook for future research into resilient shipboard systems.

It is expected that the explosion in Internet traffic implies a paradigm shift from a voice network to a data-centric network. The first and most important requirement of future transport networks is the large bandwidth transport capability which enables the paradigm shift. In addition, requirements for new service attributes are becoming more tangible. Furthermore, high reliability will be indispensable because the multimedia network will be the basis for the information society. To develop the robust and efficient networks that satisfy the requirements above, new network architectures and technologies should be developed. Photonic networks employing dense WDM technologies appear to be the solution. In this article, first the basic concept of the future photonic network is depicted. Next, the capability of large-capacity fiber transmission is shown. The critical degradation factor of fiber nonlinearity is analyzed, and the effectiveness of distributed amplification is quantitatively demonstrated. Furthermore, advances in fiber amplifiers which greatly widen the usable fiber window are shown. Other key technologies such as absolute frequency referencing and multiple channel frequency management techniques are also discussed.

Significant portion of the energy consumption of the optical networks is expected to be in the transport segment. Besides its improved bandwidth utilization advantage, multi-granular switching concept further helps rectifying the energy bottleneck problem in the backbone. One of the important challenges faced by the multi-granular optical networks is the optical reach enforcement. In this paper, we compare the multi-granular optical network design to the conventional Wavelength Division Multiplexing (WDM)-based network design by enforcing the optical reach limitation as a design constraint. We introduce the heuristics to solve the Routing and Multi-Granular Path Assignment (RMGPA) problem. Our simulation results show that multi-granular optical network design outperforms the WDM-based network design in terms of Operational Expenditure (Opex) as it significantly reduces the power consumption in the backbone. Furthermore, through simulations, we show that the green multi-granular design is efficient in terms of the Capital Expenditure (Capex) as the network cost is also degraded.