PDF of this tutorialOne of the greatest challenges service providers face today is the buildout of a network that delivers broadband and value-added services yet remains capable of economically supporting today's revenue-generating narrowband services—voice, integrated services digital network (ISDN), legacy data, and leased lines. Ironically, part of the answer to this challenge of designing the next-generation broadband network solution lies in adopting and adapting many of the attributes of today's narrowband networks: ubiquity, predictability, reliability, scalability, and manageability.
The explosion in demand for bandwidth presents another challenge for broadband services in both the core and the access edge of the network. In the core, carriers are deploying increasing amounts of fiber, utilizing dense wavelength division multiplexing (DWDM) technology, and applying bandwidth to the service quality problem that traditional router-based solutions cannot deal with. Because of this provisioning for peak loads, providers are witnessing tremendous underutilization of their network and are now realizing the potential business opportunities lost by not deploying quality of service (QoS)–capable equipment.
With the growing demand for higher-speed services, the access portion of the network is increasingly becoming the primary bottleneck. To alleviate this, new digital subscriber line (DSL) technologies are becoming available to extend the capacity of legacy copper-based facilities. However, access technologies are also about reach: having the ability to reach your customer base effectively whether "in region" or "out of region." This means multiple access technologies will be necessary for service providers to achieve the widest subscriber footprint possible. A versatile access network architecture must be capable of supporting multiple services over DSL, local multipoint distribution system (LMDS), microwave multipoint distribution system (MMDS), hybrid fiber/coax (HFC), and fiber.
