Hybrid Optical Switching and Power Consumption in Optical Networks
New applications and services are driving the demand for new high-speed transmission technologies. Wavelength division multiplexing (WDM) is able to provide the required capacity by dividing the available bandwidth into different wavelength channels, each able to support up to 100 Gbps. Several switching paradigms have been proposed for WDM networks: optical circuit switching (OCS), optical burst switching (OBS) and optical packet switching (OPS). OCS is well suited for large and stable traffic flows but it is highly inefficient in presence of bursty sources. OBS perform efficiently both in case of constant and bursty sources, but introduces high losses at the core nodes. Finally, OPS provides high bandwidth utilization but requires a large optical buffering capacity at the core nodes which is very difficult to provide. In order to combine the advantages of all the three proposed technologies, a hybrid optical switching (HOS) approach has been recently proposed. In a HOS network, large flows are transmitted using circuits or long bursts while small flows are transmitted using packets or short bursts. Even if many research activity has been done on HOS, the definition of a control plane able to deal effectively with the simultaneous presence of circuits, bursts and packets has not been defined. The aim of this research project is to define such a control plane and to evaluate its performance through simulations. Furthermore, the project aims to propose and compare different node architectures that could be managed by the proposed control plane. The architectures will be compared both from performance and power consumption side. The project aims at the definition of an optical architecture able to reduce substantially the power consumption of actual electronic routers, in agreement with the increasing interest toward green optical technologies. In order to evaluate both performance and power consumption in the proposed network a simulation model will be implemented and developed. The model will be based on C++ programming language and will be dedicated specifically for the simulation of the defined control plane and node architectures. The performance will be evaluated in terms of packet, burst and circuit loss probabilities. The network performance and power consumption will be reported in case of different technologies deployed for the realization of the network nodes. The network infrastructure will comprise edge nodes and core nodes. Edge nodes are used to connect the HOS network to legacy networks. At the edge nodes the input traffic, coming from legacy networks, is gathered and converted into the optical domain. Depending on specific traffic requirement, the input flows could be assembled either in optical packets, bursts or circuits. Core nodes are used to route traffic from ingress to egress nodes. The two main functionality of a core node are routing and the scheduling of the input traffic.