1,721,027 research outputs found
Optical networking solutions for next-generation internet networks [Guest Editorial]
No full textThe editorial calendar of IEEE Communications Magazine contains several topics relating to optical networking. This witnesses the increasing interest in optical technology to provide networking solutions for the huge growth of traffic. We would like to mention here the motivations for this feature topic specifically dedicated to optical networking solutions for next-generation Internet networks. The first issue is the significant growth of data traffic, mainly driven by Internet-based services. Several statistics and forecasts have already been reported in the literature, comparing the evolution of IP traffic to that of traditional telephone traffic. As usual, such predictions can fail in the details, the crossing points get shifted in the time frame; however, it is clear that data traffic will playa dominant role in the future of telecommunications. Actually, the traditional telecom and datacom worlds are converging. The revolution in what is generally named the "infocom" area is having an impact on the market, industrial, and scientific environments
Analysis of multicasting in photonic transport networks
No full textThe introduction of multicasting in optical transport networks is analyzed and discussed. Three different optical path realization techniques, involving the multicasting function, are examined: the Multicast Wavelength Path (MWP), the Multicast Virtual Wavelength Path (MVWP) and the Partial Multicast Virtual Wavelength Path (PVWP). A performance evaluation model is reported and results of the performance analysis are discussed. In addition several optical cross-connect architectures, allowing multicasting to be achieved, are investigated and compared. Three different types of optical switches are considered: space division, delivery and coupling, and wavelength switches. Crucial aspects as the modularity, the complexity, the costs and some transmission aspects are taken into account in the analysis
Architectural and technological issues for future optical Internet networks
No full textThis article reports a review of the most significant issues related to network architectures and technologies which will enable the realization of future optical Internet networks. The design of such networks has to take into consideration the peculiar characteristics of Internet traffic. Several architectures have been proposed to provide optical networking solutions, based on wavelength-division multiplexing and compatible with the IP world. These architectures are presented briefly, and the main advantages and drawbacks are discussed. Furthermore, advanced network architectures are reported. In particular, two network paradigms are illustrated and discussed: the optical transparent packet network and optical burst switching. Finally, the key technologies are illustrated
A new strategy for employing wavelength conversion in WDM optical networks
No full textOptical networks based on WDM technology are valid candidate for future transport networks. The wavelength routing concept allows the routing functions to be achieved directly in the optical domain, so that a channel travels throughout the network without be electrically converted. This paper proposes a new strategy, and a new algorithm that allows the strategy to be adopted, which aim the same performance of VWP to be reached, but with a strongly reduced number of wavelength converters. This means a significant saving in cost and complexity of the OXC
Optical path strategies in WDM all-optical networks: minimization of wavelength converters in optical cross-connects
No full textThere is a significant debate in progress about the need of translating the wavelength of a signal within an optical network and on the comparison of performance of WP and VWP approaches. This paper aims at investigating more in depth in this direction. An analysis of the algorithms allowing VWP and WP schemes is reported. Their performances are compared in terms of number of ports of each network node. A wavelength rearrangement algorithm is proposed which allows the performance of VWP scheme to be reached, with a strongly reduced total number of wavelength converters with respect to that corresponding to VWP. The results show a drastic reduction of wavelength converters in each node, permitting a significant reduction of the OXC costs
Routing Strategies in WDM Networks: the Impact of Transmissions Issues and Network Topology
No full textApparatus and Method for Switching Information Trasported using a Hierarchical Data Structure
No full textA switching apparatus is provided for switching information transported using a hierarchical data structure, the hierarchical data structure comprising at least first and second order data flows, The switching apparatus comprises an input stage (210) comprising at least one input switching unit (21 11 to 21 1 H), and an output stage (230) comprising at least one output switching unit (2311 to 231 H). A central stage (220) is coupled between the input stage (210) and the output stage (230), the central stage (220) comprising a central switching unit (221 ). The at least one input switching unit (21 11 to 21 1 H) and the at least one output switching unit (2311 to 231 H) are configured to switch first order data flows contained within second order data flows. The central switching unit (221 ) is configured to switch only second order data flows, wherein the second order data flows have a higher order than the first order data flows.A switching apparatus is provided for switching information transported using a hierarchical data structure, the hierarchical data structure comprising at least first and second order data flows, The switching apparatus comprises an input stage (210) comprising at least one input switching unit (21 11 to 21 1 H), and an output stage (230) comprising at least one output switching unit (2311 to 231 H). A central stage (220) is coupled between the input stage (210) and the output stage (230), the central stage (220) comprising a central switching unit (221 ). The at least one input switching unit (21 11 to 21 1 H) and the at least one output switching unit (2311 to 231 H) are configured to switch first order data flows contained within second order data flows. The central switching unit (221 ) is configured to switch only second order data flows, wherein the second order data flows have a higher order than the first order data flows
Definition and Performance Evaluation of a Low-Cost/High-Capacity Scalable Integrated OTN/WDM Switch
No full textare characterized by optical-electrical-optical (OEO) conversion of wavelength division multiplexing line wavelengths and by an electronic switching providing wavelength routing. The recent implementation of monolithically integrated large-scale photonic integrated circuits (PICs) in indium phosphide of terabit capacity cross-point switches and of high-capacity optical transport network (OTN) processor chips has allowed not only a considerable reduction in cost and power consumption of the OEO conversion stage but has also enabled the integration, in the same hardware, of OTN sub-wavelength switching and wavelength switching. To reduce the switching fabric complexity, we propose and investigate the structure of a scalable switch core composed of a space switching fabric routing only signals at a higher rate (high-order optical channel data unit (ODU)) and by OTN time-space switching fabrics switching both signals at a lower rate (low-order ODU) and a higher rate (high-order ODU). The lower hardware complexity of the proposed switching fabric is to be paid with a sub-flow blocking that we have investigated by introducing an analytical model validated by simulation. The blocking performance is evaluated as a function of the main switch and traffic parameters and under some traffic aggregation and routing policies. We show that in some traffic scenarios the blocking probability can reach a value of 10(-8) if suitable resource management policies are adopted
Integrated OTN/WDM Switching Architecture Equipped With the Minimum Number of OTN Switches
No full textIn packet-optical integrated transport nodes for metropolitan networks, the wavelength data rate of the transponders has increased quickly to 10, 40, and 100 Gbps to reduce the cost of the transported bit. Meanwhile, the majority of the client data rate in routers and packet switches are still operating at 1, 2.5, and 10 Gbps. In this scenario, the introduction of optical transport network (OTN) switching technology enables an efficient wavelength bandwidth utilization and reduces the number of wavelengths, leading to reduced network costs. It has been shown that the use of integrated OTN/WDM switch architecture is cost effective because it reduces the number of short-reach client interfaces. The OTN/WDM also reduces the rack space and the power consumption compared to an architecture that uses a reconfigurable optical add-drop multiplexer and a separate standalone OTN switch or one that uses back-to-back muxponder connections to perform manual grooming. We introduce and investigate the performance of a new integrated OTN/WDN switching architecture in which the number of OTN switches is minimized. We propose an analytical model for the evaluation of the switch-blocking probability when two different OTN switch assignment policies are used. We show how the number of OTN switches can be reduced if a suitable dimensioning procedure is performed and depending on the traffic percentage needing OTN switching. As an example, if traffic is less than 45%, then the new proposed OTN/WDM switching architecture allows for 25% savings in OTN switching resources in the case of a switch with 4 input/output lines, 48 wavelengths, and 12 x 12 OTN switches.In packet-optical integrated transport nodes for metropolitan networks, the wavelength data rate of the transponders has increased quickly to 10, 40, and 100 Gbps to reduce the cost of the transported bit. Meanwhile, the majority of the client data rate in routers and packet switches are still operating at 1, 2.5, and 10 Gbps. In this scenario, the introduction of optical transport network (OTN) switching technology enables an efficient wavelength bandwidth utilization and reduces the number of wavelengths, leading to reduced network costs. It has been shown that the use of integrated OTN/WDMswitch architecture is cost effective because it reduces the number of short-reach client interfaces. The OTN/WDM also reduces the rack space and the power consumption compared to an architecture that uses a reconfigurable optical add–drop multiplexer and a separate standalone OTN switch or one that uses back-to-back muxponder connections to perform manual grooming.We introduce and investigate th
Patent number 12712121.8 - 1855: Apparatus and Method for Switching Information Trasported using a Hierarchical Data Structure
No full textA switching apparatus is provided for switching information transported using a hierarchical data structure, the hierarchical data structure comprising at least first and second order data flows, The switching apparatus comprises an input stage (210) comprising at least one input switching unit (21 11 to 21 1 H), and an output stage (230) comprising at least one output switching unit (2311 to 231 H). A central stage (220) is coupled between the input stage (210) and the output stage (230), the central stage (220) comprising a central switching unit (221 ). The at least one input switching unit (21 11 to 21 1 H) and the at least one output switching unit (2311 to 231 H) are configured to switch first order data flows contained within second order data flows. The central switching unit (221 ) is configured to switch only second order data flows, wherein the second order data flows have a higher order than the first order data flows
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