Optical WDM networks: Traffic grooming in mesh networks and metro networks using ROADMs.

摘要

Optical Fiber technology employing wavelength-division multiplexing (WDM) has and continues to be investigated and commercially deployed to meet our ever-increasing bandwidth demands. WDM partitions the huge bandwidth of an optical fiber into many non-overlapping wavelength channels, each of which can operate at the data rate of 10 Gbps (or 40 Gbps or higher). This dissertation investigates design and modeling issues of optical WDM mesh networks, as well as ring networks.; This dissertation first proposes a novel generic graph model for traffic grooming in heterogeneous WDM mesh networks so that low-speed traffic streams can be "groomed" (or carried) by high-capacity wavelength channels. This model uses an auxiliary graph to represent the network state, which can accommodate various resource constraints. It can achieve different grooming policies by employing a simple shortest-path algorithm, and it can be applied to both static and dynamic traffic-grooming scenarios.; A grooming policy determines how to carry the traffic in a certain situation. It reflects the intention of a network operator. Different grooming policies are explored in both static and dynamic traffic environments in this dissertation.; Various architectures and technologies can be employed when building optical crossconnects (OXCs). Thus, different OXCs might have different switching granularities and different OXC port costs. This dissertation investigates how to cost effectively design a network using OXCs of different switching granularities to leverage the advantages of various OXCs. We significantly enhance the graph model to cover the characteristic of switching granularity, and propose a network design procedure, which reduces the network-wide port costs. Optical Add/Drop Multiplexers can significantly reduce the cost of metro optical WDM ring networks by allowing traffic to bypass intermediate nodes without expensive opto-electro-opto conversion. Reconfigurable Optical Add/Drop Multiplexers (ROADMs) are emerging which can add/drop traffic onto/from different wavelengths at different times. ROADMs provide desirable flexibility, enable fast provisioning of dynamic traffic, and save capital expenditure and operational expenditure. This dissertation investigates the design and the benefits of metro optical WDM network architectures using ROADMs, identifies the tuning constraints of certain architectures, and studies the impact of this tuning constraint on the performance of the network.