The SNC Nominal Route is the default or preferred route that is assigned to an LSP when it is created. The SNC Nominal Route is determined by the constraints that are specified by the user during the LSP creation process, such as cost, SRLG, color, bandwidth, protection, and regeneration. The user can modify the SNC Nominal Route in NFM-T by using the Constraint Wizard, which is a tool that allows the user to change the constraints for an existing LSP. The Constraint Wizard will then compute a new SNC Nominal Route based on the modified constraints and update the LSP accordingly34. References:

• 3: Nokia GMPLS-controlled Optical Networks Course | Nokia
• 4: Nokia Network Functions Manager for Transport User Guide | Nokia

The Shutting Down state is a transient state that occurs when a TE-link is set to maintenance mode in the NFM-T. In this state, the TE-link is not available for routing new LSPs, but the existing LSPs (SNCs) that use the TE-link are not immediately terminated. Instead, they are soft-rerouted, which means that they are gracefully switched to alternative paths without disrupting the traffic. The Shutting Down state lasts until all the SNCs on the TE-link are successfully soft-rerouted or forcefully terminated. After that, the TE-link transitions to the Administrative Maintenance state, where no traffic can be routed over the TE-link12. References:

• 1: Nokia GMPLS-controlled Optical Networks Course | Nokia
• 2: Nokia Network Functions Manager for Transport User Guide | Nokia

To configure the Trail template in NFM-T for an Uplink board (such as 2UC400) in a network with only LI restoration capability, you need to check the Logical Link box, set the Port Type to Unterminated, uncheck the ASON Routed box, and uncheck the ASON Tunnel box. This configuration allows you to create a logical link between two Uplink boards that can be used for LI restoration. The logical link is not terminated at the Uplink board, but at the OTU board. The ASON Routed option is not needed for LI restoration, as the LSPs are established by NFM-T and not by GMPLS. The ASON Tunnel option is not applicable for Uplink boards. References : Nokia Advanced Optical Network Management with NFM-T Course | Nokia, Nokia 1830 PSS-4, PSS-8, PSS-16 and PSS-32 Platforms - NATO

A network with ROADM GMPLS nodes and optical transponder connections could have both L0 and L1 restoration capabilities. L0 restoration refers to the ability of the network to recover from failures at the optical layer, such as fiber cuts or node failures, by rerouting the affected LSPs to alternative paths at the same layer. L0 restoration can be achieved by using GMPLS signaling protocols, such as RSVP-TE or CR-LDP, to establish backup LSPs in advance or on demand. L0 restoration can provide fast recovery times and high availability for optical services34. L1 restoration refers to the ability of the network to recover from failures at the sub-wavelength layer, such as transponder failures or wavelength unavailability, by rerouting the affected LSPs to alternative paths at a higher layer. L1 restoration can be achieved by using GMPLS routing protocols, such as OSPF-TE or ISIS-TE, to advertise the sub-wavelength information and availability to other nodes in the network. L1 restoration can provide more flexibility and efficiency for sub-wavelength services56. References:

• 3: GMPLS - Nokia
• 4: Generalized Multi-Protocol Label Switching - Wikipedia
• 5: Sub-Wavelength Switching - Nokia
• 6: Sub-Wavelength Switching in Optical Networks - IEEE Xplore

 Coordination of L0 and L1 resources in case of a failure in an MRN is achieved by setting the color constraints. Color constraints are used to specify which wavelengths or timeslots can be used by a given LSP request. By setting the color constraints, the NFM-T can ensure that the L0 and L1 resources are compatible and consistent across the network. For example, if an L0 LSP request requires a specific wavelength, the NFM-T can set the color constraint to match that wavelength and assign it to the L0 LSP. Similarly, if an L1 LSP request requires a specific timeslot, the NFM-T can set the color constraint to match that timeslot and assign it to the L1 LSP. This way, the coordination of L0 and L1 resources is achieved by ensuring that the same color is used by both layers. References : Nokia GMPLS-controlled Optical Networks Course | Nokia, 3. GMPLS - Nokia

The Feasibility File is a file that contains a set of target values for various optical impairment parameters, such as OSNR, CD, PMD, and PDL, that are used to determine whether a given LSP can be routed through the GMRE network. The Feasibility File is generated by the Network Planning Application (NPA) based on the network design and the service requirements. The Feasibility File is then loaded into the GMRE nodes and used by the GMPLS routing engine to perform feasibility checks for LSP requests. The Feasibility File ensures that the LSPs are routed in accordance with the network plan and the optical performance criteria12. References:

• 1: Nokia GMPLS-controlled Optical Networks Course | Nokia
• 2: GMPLS - Nokia

Quality of Service (QoS) in GMPLS is the ability to set constraints such as latency and priority for different kinds of services. This means that GMPLS can allocate network resources according to the specific requirements of each service, such as voice, video, or data. For example, a voice service may need low latency and high priority, while a data service may need high bandwidth and low priority. GMPLS can use Traffic Engineering (TE) extensions to OSPF and RSVP protocols to advertise and reserve network resources based on QoS parameters. References : [Nokia GMPLS-controlled Optical Networks Course | Nokia], [Quality of Service - Nokia]