Open Access Networks: Operating Options and Challenges of Business Logic

Switching fabric is a hardware mechanism used inside packet switches and routers to provide an interconnection among I/O ports and possibly a CPU. The ideal switching fabric scales to handle a high data rate on a given port, and scales to handle many ports. Because practical switching fabrics cannot achieve the ideal, a set of architectures has been created of which each represents a trade off in performance, scalability, and cost. We discuss different switching fabric architectures, analyze bandwidth requirements, and examine interconnection mechanisms that can be used to create a fast path over which packets move from one network interface to another. Most of today's packet switches and routers are implemented using slower electronic components. Dense wavelength-division multiplexing (DWDM) technology offers tremendous transmission capacity in optical fiber communications. Optical packet switches are one of the potential candidates to improve switching capacity to be comparable with optical transmission capacity. The WDM switching fabric stores and forwards cells from each input port to one or more specific output ports determined by the electronic route controller. Using this kind of optical switch to route information, an optical network has the advantage of bit rate