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Due to the constantly increasing volumes and tightening reliability requirements of network traffic, survivability is one of the key concerns in optical network design. Optical “white box” nodes based on the Architecture on Demand (AoD) paradigm allow for self-healing of nodal component failures due to their architectural flexibility and the ability to employ idle components for failure recovery....
This paper is presenting the simulation of fiber taper. A travelling burner tapering system which implements the ‘flame-brush’ technique is selected for the fiber tapering. The important parameters that control the shape of fiber taper and the related mathematical equation for shaping the fiber taper were understood and then transformed into software codes for further simulation. Both Forward and...
The paper presents a Specification and Description Language (SDL) based approach to software process modeling. A brief review of other process modeling languages is given and the advantages of the ITU-T standardized SDL for formal model development are outline. Further on, it is shown how software process entities are modeled using SDL. Software maintenance process performed in a large telecommunications...
Network resilience is an issue of deep concern to network operators being eager to deploy high-capacity fibre networks, since a single failure in the network could result in significant losses of revenue. The importance of network reliability will keep pace with the steadily increasing network capacity. For very-high-capacity future optical networks, carrying multitudes of 10 Gbit/s channels per fibre...
COST – the acronym for European COoperation in Science and Technology – is the oldest and widest European intergovernmental network for cooperation in - search. Established by the Ministerial Conference in November 1971, COST is presently used by the scientific communities of 35 European countries to coop- ate in common research projects supported by national funds. The funds provided by COST – less...
Due to the large transmission speeds and enormous volumes of transferred data, network availability performance is one of the key issues in optical long-haul networks, comprising nodes implemented by optical cross-connects (OXCs). In this context, the design of OXCs is becoming very challenging since they have to support both legacy lower bit-rates and future highspeed super-channels by means of flexible...
The study focuses on optimization of optical networks based on function programmable ROADMs implemented by Architecture on Demand (AoD) under a multi-hour traffic scenario. The objective is to minimize the cost and energy consumption by reducing the number of active modules inside the nodes, and to investigate the impact of network reconfiguration frequency to potential savings and lightpath availability...
Network availability is an essential feature of an optical telecommunication network. Should a failure of a network component occur, be it a link or a component inside a node, network control plane must be able to detect the failure and reroute the traffic using spare components until a repair is done. Shared risk link groups (SRLGs) are used to describe a situation where seemingly unrelated logical...
The paper demonstrates the concept of optical networks with nodes implemented by the architecture on demand (AoD) and proposes a procedure for finding out possible benefits of AoD application, related to node and network availability. AoD node structure enables efficient failure management by creating a set of redundant components, which can be used for self-healing of optical nodes after failure...
Network availability is of paramount importance in optical telecommunication networks. Their rising connectivity and consequently their availability is compromised by link and node failures, usually due to physical force (e.g. digging, earthquake or fire). Single link failures can in turn cause multiple failures in case a failure hits a shared risk link group (SRLG), which is a group of logically...
Optical backbone networks are carrying enormous amount of traffic and therefore, network reliability performance is extremely important to minimize the service interruption time and loss of data. Besides, increasing energy consumption of the ICT sector makes network energy efficiency gain a lot of attention. Reducing the usage of components in the network is a promising strategy to both make network...
Novel hard-wired and synthetic ROADM architectures with self-healing capabilities are experimentally demonstrated. Simulation results show significant improvements of availability and recovery time due to node-level restoration, with reduced mean down time and operator revenue losses.
In optical networks a group of logically distinct links can unintentionally share a physical resource (e.g, a cable or a duct). Such a group, called shared risk link group (SRLG), introduces a situation where a single failure of common resource can cause multiple failures. Failure of common resource usually occurs due to physical force (e.g, digging or earthquake) and causes failures of multiple links...
Architecture on Demand (AoD) can provide self-healing at the optical node level due to its flexibility and the ability to employ idle components for failure recovery. We study the impact of AoD on network availability at different traffic switching granularities, showing significant improvements compared to traditional static node architecture.
The paper presents analytical and simulation availability models for evaluation of optical node availability. Analytical models are developed for six ROADM (reconfigurable optical add and drop multiplexers) architectures. Availability/cost figures are calculated, compared and discussed. For one of ROADMs simulation model is created and Monte Carlo simulation of times to failure and times to repair...
In the paper is presented developed software tool intended for assessment of Fiber To The Home (FTTH) next generation optical access networks. The software tool CABE is based on mathematical models that comprise aspects of network Cost, Availability, Bandwidth and Energy. The models include specific requirements for analysis of access networks in urban, suburban and rural areas. Prediction of the...
The paper describes the design goals and methodology in creating a new model of optical telecommunication network. The model is implemented by discrete-event network simulator ns-3. The advantages of using the existing simulator core infrastructure provided by ns-3 are analyzed and compared to building own simulator from scratch, or selecting a tool among other existing simulators such as ns-2, OMNeT++,...
The provisioning of services in optical networks requires reliable optical cross-connects. The paper presents advantages of architectures on demand (AoD) for optical cross-connects comparing to non AoD architectures in terms of availability. All conclusions come from analytical calculations verified by path set enumeration and Abraham's algorithm.
The paper presents the heuristic approach to availability analysis of optical communication networks connecting ship's systems. The availabilities of individual components have been calculated, as the basis for the entire system availability evaluation. Several network availability structures and protection scenarios are presented and the availability evaluated. Based on the analysis, the possibility...
The application of all-optical switching fabrics will be an important breakthrough in avoiding capacity bottleneck caused by electronic-switching in optical networks. All-optical domain of achieved network is characterised by absence of optical-electrical-optical conversions. In this paper, the-state-of-the-art of optical switching fabrics used in optical cross-connect is reviewed. Moreover, availability...
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