etworks need switches capable of rerouting light. The good news is that the cost of optical components has decreased by 40% in recent years, and it is expected to continue to drop by 40% to 60% per year. The biggest problem that converged telcos are now facing is how to accurately forecast their future bandwidth requirements. Transmission speeds are doubling every 12 months, SO it is essential that we have infrastructures capable of providing a large amount of bandwidth on short notice and at reasonable cost. Without intel- ligent optical networking, adding an OC-48 circuit over existing dark fiber can take between 6 and 9 months. To automate provisioning, we need to also address how we can look into a wavelength to determine how to properly act on it. Optical switches enable improved reliability, improved scalability, and flexible service provisioning. They also reduce the capital required to add additional capac- ity, and the overall savings can then be passed on to the customer. Deploying opti- cal networking technology in the metro area can bring the benefits of converged networks down to the customer's premises. The end-to-end optical infrastructure can then support advanced services such as true bandwidth-on-demand. Optical Switching Fabrics Optical switches are components in a fiber-optic network that direct light beams from one fiber to another, and they are used as an alternative to hubs for routing connections. Optical switching fabrics, such as the following, can provide sub- systems that connect one wavelength to another: End-to-End Optical Networking Microelectromechanical system (MEMS) switches-A MEMS switch uses an array of microscopic mirrors to reflect light from an input port to an out- put port. Bubble switches-Similar to inkjet printers, bubble switches use heat to create small bubbles in fluid channels that then reflect and direct light. Thermo-optical switches-With thermo-optical switches, light passing through glass is heated up or cooled down by using electrical coils. The heat alters the 