A survey on OFDM-based elastic core optical networking

Orthogonal frequency-division multiplexing (OFDM) is a modulation technology that has been widely adopted in many new and emerging broadband wireless and wireline communication systems. Due to its capability to transmit a high-speed data stream using multiple spectral-overlapped lower-speed subcarriers, OFDM technology offers superior advantages of high spectrum efficiency, robustness against inter-carrier and inter-symbol interference, adaptability to server channel conditions, etc. In recent years, there have been intensive studies on optical OFDM (O-OFDM) transmission technologies, and it is considered a promising technology for future ultra-high-speed optical transmission. Based on O-OFDM technology, a novel elastic optical network architecture with immense flexibility and scalability in spectrum allocation and data rate accommodation could be built to support diverse services and the rapid growth of Internet traffic in the future. In this paper, we present a comprehensive survey on OFDM-based elastic optical network technologies, including basic principles of OFDM, O-OFDM technologies, the architectures of OFDM-based elastic core optical networks, and related key enabling technologies. The main advantages and issues of OFDM-based elastic core optical networks that are under research are also discussed

Design of survivable WDM network based on pre-configured protection cycle

Wavelength Division Multiplexing (WDM) is an important technique which allows the trans- port of large quantities of data over optical networks. All optical WDM-based networks have been used to improve overall communication capacity and provide an excellent choice for the design of backbone networks. However, due to the high traffic load that each link can carry in a WDM network, survivability against failures becomes very important. Survivability in this context is the ability of the network to maintain continuity of service against failures, since a failure can lead to huge data losses. In recent years, many survivability mechanisms have been studied and their performance assessed through capacity efficiency, restoration time and restorability. Survivability mechanisms for ring and mesh topologies have received particular attention

Application-Aware Protection in DWDM Optical Networks

International audienceFast recovery time and reduced resource utilization are the two main criteria for determining the quality of survivability mechanism. Now it is well-known that link-based protection and path-based protection provide respectively a short recovery time and reduced use of resources. To benefit from the both of these saliencies, we propose in this paper to use these mechanisms simultaneously. Indeed, demands mandating shorter recovery time will be protected using link-based protection. Meanwhile other demands will be protected using path-based protection. Simulation results show that the proposed solution achieves a good trade-off between resource utilization and recovery time

Optimal Regenerator Placement for Dedicated Path Protection in Impairment-Aware WDM Networks

Building resilient Wavelength Division Multiplexed (WDM) optical networks is an important area of research. This thesis deals with the design of reliable WDM networks where physical layer impairments are taken into account. This research addresses both the regenerator placement problem (RPP) and the routing with regenerator problem (RRP) in impairment-aware WDM networks, using dedicated path protection. Both the problems have been tackled using linear Integer formulations which can be implemented, using a solver such as the CPLEX. For solving RPP, two solutions have been proposed - i) a formulation that gives optimal solutions which works only for small networks, and ii) a highly effective heuristic which given an optimal solution in 97.5 to 99% of cases for networks having a size up to 60 nodes

Next-Generation Transport Networks Leveraging Universal Traffic Switching and Flexible Optical Transponders

Recent developments in communication technology contributed to the growth of network traffic exponentially. Cost per bit has to necessarily suffer an inverse trend, posing several challenges to network operators. Optical transport networks are no exception to this. On one hand, they have to keep up with the expectations of data speed, volume, and growth at the agreed quality-of-service (QoS), while on the other hand, a steep downward trend of the cost per bit is a matter of concern. Thus, the proper selection of network architecture, technology, resiliency schemes, and traffic handling contributes to the total cost of ownership (TCO). In this context, this chapter looks into the network architectures, including the optical transport network (OTN) switch (both traditional and universal), resiliency schemes (protection and restoration), flexible-rate line interfaces, and an overall strategy of handover in between metro and core networks. A design framework is also described and used to support the case studies reported in this chapter