In this case generally, peer-to-peer services also transit through a core node before being delivered to destination, even if both the source and destination are in the same metro area. In this architecture, the metro network has the role of effectively transporting the sig- nals consolidated by the access equipment to the core. In the United States on the contrary, traditionally, the local carriers were separated from the core carriers. This means that router boxes (RBOCs), being in the position not to own the core network, were forced to deploy a great part of the service sources and authenti- cation machines into the metro area. Even if the carrier scenario in the United States has changed as a consequence of a few huge mergers in the last few years, the network archi- tecture has not changed. When the content sources and the authentication machines are located in metro nodes, the metro network task changes slightly, since besides grooming and transport toward core nodes, the metro network also performs direct connections between couples of its nodes. After access and metro areas, the network is completed by the core, the part of the network whose role is to transport aggregated signals over very long distances and, in many cases, to host in the core central offices the machines for content delivery and users authentication. 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. 3.1.2 Access Network Architecture The copper network is a completely passive structure connecting every end user with the local exchange using a dedicated twisted pair [6]. In different parts of the network, different cables are used, composed of a different num- ber of copper pairs. When a type of cable is terminated and the copper pairs are divided into smaller cables, the needed patch panel is contained in a street cabinet, called partition cabinet. Generally, there are two levels of partition cab