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Unformatted text preview: 476 Control and Management 8.2 Optical Layer Services and Interfacing The optical layer provides lightpaths to other layers such as the SONET/SDH, IP/MPLS, and Ethernet layers, as well as the electronic layer of the Optical Trans- port Network (OTN), which includes the the optical channel transport unit (OTU) and optical channel data unit (ODU) sublayers (see Section 6.2). In this context, the optical layer can be viewed as a server layer, and the higher layer that makes use of the services provided by the optical layer as the client layer. From this perspective, we need to specify clearly the service interface between the optical layer and its client layers. The key attributes of such a managed lightpath service are the following: Lightpaths need to be set up and taken down as required by the client layer and as required for network maintenance. Lightpath bandwidths need to be negotiated between the client layer and the optical layer. Typically, the client layer specifies the amount of bandwidth needed on the lightpath. An adaptation function may be required at the input and output of the optical network to convert client signals to signals that are compatible with the optical layer. This function is typically provided by transponders, as we discussed in Section 7.1. The specific range of signal types, including bit rates and protocols supported, need to be established between the client and the optical layer.supported, need to be established between the client and the optical layer....
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- Spring '09
- Object-Oriented Programming, Optical Transport Network