Optimized traffic profile for FlexGrid optical networks

This work is focused on studying the connections’ bandwidth distribution effects on the FlexGrid network performance. An accurate study of spectrum occupancy in heavy loaded FlexGrid optical networks is carried out. This analysis is useful to figure out which traffic profiles are more suitable for this kind of networks. Two different cases are considered with respect to the offered connections. In the elastic case, connections sizes can take any value from 1 to a maximum number of spectrum slots. In the multi-rate case, only three connections sizes are allowed. It is demonstrated that by generating the connections with some specific statistical properties, the network performance is improved. These properties are derived from the theoretical study of spectrum occupation in ideal conditions. The main contribution of this work is therefore the proposal of an Optimum traffic profile which allows to efficiently use the spectrum in FlexGrid optical networks. The gain obtained by generating the proposed traffic profile is evaluated by means of simulations at the link as well as at the whole network level.Peer ReviewedPostprint (author's final draft

Impact of filter sharpness on the performance of elastic optical networks

Elastic optical network (EON) technology arises as a promising solution for future high-speed optical transport networks, inasmuch as it can provide superior flexibility and scalability in the spectrum allocation for seamlessly supporting a disparity of services, while coping with the rapid growth of Internet traffic. Spectrally efficient lightpath establishment in EONs is enabled by recent developments in flex-grid transceivers and wavelength selective switches (WSS), which are the key players in determining the amount of spectrum that needs to be reserved for a connection as well as the guard band (GB) required between adjacent channels, since the imperfect shape of the filters degrades the spectrum utilization efficiency of the network. In this paper, we focus on the impact of the filter sharpness on the performance of EONs from the networking perspective. In this regard, we initially quantify the effect of the sharpness of a transmitter Nyquist shaping filter and an LCoSbased WSS filter on the amount of spectrum required for efficient connection establishment. Subsequently, we investigate the practicality of moving to finer frequency slot sizes and, based on extensive simulation results, evaluate the improvement in terms of network blocking probability that can be obtained by using sharper filters.Peer ReviewedPostprint (published version

Impact of filter sharpness on the performance of elastic optical networks

Elastic optical network (EON) technology arises as a promising solution for future high-speed optical transport networks, inasmuch as it can provide superior flexibility and scalability in the spectrum allocation for seamlessly supporting a disparity of services, while coping with the rapid growth of Internet traffic. Spectrally efficient lightpath establishment in EONs is enabled by recent developments in flex-grid transceivers and wavelength selective switches (WSS), which are the key players in determining the amount of spectrum that needs to be reserved for a connection as well as the guard band (GB) required between adjacent channels, since the imperfect shape of the filters degrades the spectrum utilization efficiency of the network. In this paper, we focus on the impact of the filter sharpness on the performance of EONs from the networking perspective. In this regard, we initially quantify the effect of the sharpness of a transmitter Nyquist shaping filter and an LCoSbased WSS filter on the amount of spectrum required for efficient connection establishment. Subsequently, we investigate the practicality of moving to finer frequency slot sizes and, based on extensive simulation results, evaluate the improvement in terms of network blocking probability that can be obtained by using sharper filters.Peer Reviewe