resource utilization, difficult interopera- bility between packet client networks and circuit-switched optical networks, complex network management, difficult interoperability between networks belong- ing to different operators, and lack of protection in mesh-type optical networks. Network operators implementing the ASON control plane can expect increased revenue-generating capabilities, reduced operational cost, and increased return on capital. Additional benefits to operators include better resource utilization, reduction of manual intervention, simplification of network management systems, support for Chapter 11 Optical Networking all-optical networks, and easier internetworking. The major benefits to customers include new services, reduction of service provisioning times, VPNs and closed user groups, bandwidth-on-demand services, provisioned bandwidth services, and wider SLA support capability. An ASON network allows for three types of connections: permanent connec- tions (established and controlled by a TMN), soft permanent connections (estab- lished by a TMN but controlled over the ASON plane), and switched connections (established and controlled by the ASON network). The Migration to Optical Networking There are still many challenges to building a pure optical network. Optical networks are expensive and require a wide range of new equipment and systems, including Tbps switch routers, pure optical switches, DWDM and CWDM muxes, optical cross-connects, optical repeaters and regenerators, optical components and inte- grated photonic circuits, new generations of fiber-optic cable, new fiber construction approaches, and, of course, optical network maintenance and management tools. Some of the challenges to building a pure optical network include the fact that incumbent carriers are not healthy financially. They traditionally build only when there's proven demand and return on investment. Many new entrants have basi- cally gone bust. Carriers can no longer afford the "if you build it, they will come" strategy. T