Optical metropolitan DWDM networks an overview

ABSTRACT The paper deals with the subject of how to build a core network in the current technology scenario. We start with an overview ofwhat we consider a core network, not in an abstract way but referring to real country situations, and pointing out the differentaspects conditioning its realisation – population distribution, territory shape, traffic characteristics. In the next section asummary of different network topologies is presented and briefly analysed – rings, meshes, loosely or tightly interconnected,with particular attention to the resilience aspect in case of faults. The following section is dedicated to a short presentation of thecurrent technology scenario and how it reflects on the network elements (NEs) offered on the market (OXC, OADM, PXC, etc).Finally, the question is posed: “What is the best way to implement a core network?” with the conclusion being that there is nosingle answer – each situation must be pursued on a case-by-case basis.