ABSTRACT
This chapter discusses the situation of the most advanced networks, considering only wire-line access. The telecommunication network is perhaps the most complex infrastructure deployed by humankind. It is pervasive, reaching almost all parts of the world, and exploits a wide set of different technologies. A telecommunication network spans a wide geographical area and is composed of different types of equipment. In the architecture, the metro network has the role of effectively transporting the signals consolidated by the access equipment to the core. The most important network elements in terms of technology are deployed in the core network that in general is characterized by a small number of nodes and very long span transmission systems. A critical characteristic of a copper-based access network is the average length of the user line. The metro network collects signals from the access central offices and delivers it generally to the core nodes.
