 of IP and optical naturally leads us to GMPLS, offering an end-to-end unified solution. The UNI for the GMPLS specification, as discussed earlier in this chapter, allows for neighbor discovery and channel assignment at the SDH/SONET level. The con- trol interface can be an out-of-band Ethernet interface or an in-band command car- ried in the SDH/SONET overhead. The UNI specifies a way for a client, called a UNI client, to invoke transport network services with a UNI network, a device on another provider's network. Today, UNI is limited to three actions: connection cre- ation, connection deletion, and connection status inquiry. As discussed earlier in this chapter, ASON is based on a technology that enables automatic delivery of transport services. Specifically, an ASON network can deliver not only leased-lines connections but also other transport services, such as soft permanent and switched optical connections. In an ASON network, each network node should be equipped with a control plane. The control plane sets up and releases connections and can restore a connection in case of a failure. ASON optical network elements will take over a number of tasks from the Telecommunications Management Network (TMN) architecture, including rout- ing, restoration, service provisioning, admission control, and accounting. This requires the migration of OTN from a TMN-controlled network to a distributed approach: ASON. ASON is still in its early stages but will likely complement opti- cal UNIs as well as GMPLS. The major features of ASON include fast provisioning, easy network operation, increased network reliability, scalability, and simple plan- ning and design. Although current optical networks offer enormous capacity compared to their IP counterparts, they are quite inflexible. Most of the limitations are a result of the fact that they are operated manually or via complex and slow network management systems. Drawbacks of existing optical networks include error-prone manual provi- sioning, long provisioning time, inefficient 