d cost the provider $960,000. There are also certain key OAM&P implications for metro core WDM networks. At this time, long-haul applications do not require dynamic man- agement of individual wavelengths (except with new architectures such as Generalized MPLS (GMPLS), which is discussed in Chapter 8, "GMPLS in Optical Networks"). Therefore, one optical surveillance channel carried on a dedicated wavelength is sufficient to control and monitor all remote WDM network elements such as OLAs. Photonic networks in metropolitan access and interoffice applications manage individual wavelengths. Because indi- vidual wavelengths have different endpoints and take different paths across the network, one optical surveillance channel carried on a separate wavelength is not sufficient. Fault information is required for and must accompany each wavelength. Per-wavelength fault information is needed for fault detection and isolation, which are necessary to support survivabil- ity mechanisms and trigger fast maintenance and repair actions. In pho- tonic networks, service providers can also verify the connectivity and monitor the performance of each connection. Proponents make the case that with metro DWDM, user requests for increased bandwidth or different protocols can be filled quickly, so the net- work provider can realize increased revenue. This may be true in the metro core network, but it is unlikely that it can be achieved in general in the metro access. New services such as optical-channel leased lines that provide end-to-end protocol and bit-rate-independent connections can be offered, affording new revenue for the network provider. In WDM-based photonic networks, transport interfaces that are specific to protocol and bit rates are no longer required, minimizing the network provider's inventory and oper- ating costs. On the other hand, it is important to keep in mind that the market for traditional handoffs from intranet routers will continue to exist for many years and may in fact exceed the Ethernet-handoff market for th