The past decade has witnessed significant development in the area of optical networking. Such advanced technologies as dense wavelength division multiplexing (DWDM), optical amplification, optical path routing (wavelength cross-connect), wavelength add-drop multiplexer (WADM), and high-speed switching have found their way into the wide-area networks (WANs), resulting in a substantial increase of the telecommunications backbone capacity and greatly improved reliability.

At the same time, enterprise networks almost universally converged on 100 Mbps Fast Ethernet architecture. Some mission-critical local-area networks (LANs) even moved to 1000 Mbps rates, courtesy of a new Gigabit Ethernet standard recently adopted by the Institute of Electrical and Electronics Engineers (IEEE).

An increasing number of households have more than one computer. Home networks allow multiple computers to share a single printer or a single Internet connection. Most often, a home network is built using a low-cost switch or a hub that can interconnect 4 to 16 devices. Builders of new houses now offer an option of wiring a new house with a category-5 (CAT-5) cable. Older houses have an option of using existing phone wiring, in-house power lines, or an evermore popular wireless network, based on the IEEE 802.11 standard. Different flavors of this standard can provide up to 11 Mbps bandwidth or up to 54 Mbps bandwidth, with distance being a tradeoff. Whether it is a...