Voice Over IP

THE HYBRID/FIBER COAX (HFC) APPROACH

Hybrid/fiber coax (HFC) systems have been deployed in some suburban neighborhoods in several countries, and they are now slowly finding their way into the North American market. The supporters of this approach believe that ADSL technology (over the conventional twisted pair) does not provide enough bandwidth in relation to its costs. The HFC technology exploits the bandwidth capacity of fiber and coax.

As shown in Figure 5-8, the HFC network has an optical fiber facility running from the central office (the headend) to a neighborhood node. The fiber has forward and return paths. At the node, users are connected by coaxial cable.

Figure 5-8. The HFC configuration

Figure 5-9 shows a typical hybrid fiber ...