Nokia 4A0-220 - Nokia GMPLS-Controlled Optical Networks

Test Mode is a feature of the Link Management Protocol (LMP) that allows testing the connectivity and functionality of a link or a TE-link. Test Mode can be initiated by either end of a link or a TE-link by sending a Test Message with a Test ID and a Test Pattern. The Test Message is sent over the control channel of the link or the TE-link and contains information such as the source and destination IP addresses, the link ID, and the test parameters. The receiving node then verifies the Test Message and sends back a TestStatusAck message with the same Test ID and Test Pattern. The TestStatusAck message indicates whether the test was successful or not, and if not, what was the reason for failure. Test Mode can be used to check if a link or a TE-link is operational, if it has any errors or faults, or if it supports certain features or capabilities. References : Nokia GMPLS-controlled Optical Networks Course | Nokia, RFC 4204 - Link Management Protocol (LMP)

A distributed control plane for GMPLS means that each router has software to run the GMPLS protocols and can modify the node’s switching fabric. This allows the routers to communicate with each other and establish Label Switched Paths (LSPs) across the network without relying on a centralized controller or network manager. A distributed control plane can improve the scalability, reliability, and efficiency of the network. References : Nokia GMPLS-controlled Optical Networks Course | Nokia, GMPLS - Nokia

Automation is one of the key features of GMPLS that allows dynamic provisioning of optical transport connections between IP routers and optical network elements2. Automation reduces the operational time and administrative overhead required to provision new connectivity, which in turn reduces the operational expenditure (OPEX) of the network. Reducing CAPEX, providing resilience against multiple failures, and supporting multi-vendor networks are not direct benefits of automation, but rather possible outcomes of using GMPLS in general. References:

1: Nokia GMPLS-controlled Optical Networks Course | Nokia

2: GMPLS - Nokia

3: Traffic survivability through Protection and Restoration Combined (PRC) - YouTube

[4]: GMPLS: Architecture and Applications - Google Books

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 an MRN network with LO and LI restoration capabilities, you need to check the Logical Link box, set the Port Type to Unterminated, check 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 LO or LI restoration. The logical link is not terminated at the Uplink board, but at the OTU board. The ASON Routed option enables the GMPLS control plane for the logical link, while 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 Nominal Route in a GMPLS network is the optimal path that meets the Traffic Engineering (TE) constraints for a given LSP request. A Nominal Route is calculated by the NFM-T using the Constrained Shortest Path First (CSPF) algorithm, which takes into account parameters such as bandwidth, latency, priority, protection type, and other QoS attributes. A Nominal Route is stored in the NFM-T database and can be used to provision LSPs over the network. A Nominal Route can differ from the Current Route, which is the actual path that the LSP is taking at a given time, due to network changes or failures. References : Nokia GMPLS-controlled Optical Networks Course | Nokia, Nokia Advanced Optical Network Management with NFM-T Course | Nokia

 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

GMPLS-enabled nodes use routing protocols, such as OSPF-TE or ISIS-TE, to exchange information about the topology and the state of the links in the network12. This information includes the link attributes, such as bandwidth, wavelength, protection, and shared risk link groups (SRLGs)3. The state of each link indicates whether it is up or down, available or reserved, and so on. This information is used by GMPLS-enabled nodes to compute feasible paths for LSPs and to avoid routing loops or conflicts. The bandwidth and the frequency of each client path are not present in every GMPLS-enabled node, but only in the ingress and egress nodes that initiate and terminate the LSPs. The list of LSPs created in the entire network is also not present in every GMPLS-enabled node, but only in the nodes that are involved in the LSPs or that maintain a global view of the network. References:

1: GMPLS - Nokia

2: Generalized Multi-Protocol Label Switching - Wikipedia

3: Nokia GMPLS-controlled Optical Networks Course | Nokia

The provisioning steps that are common in both CP to plain MP networks are node creation, CPB provisioning process, node synchronization, and CPB power balance. These steps are required to create and commission the nodes, provision the cross-connect boards (CPBs), associate the links between the nodes, synchronize the network elements (NEs) with the NFM-T, and balance the power levels of the CPBs. References : Nokia GMPLS-controlled Optical Networks Course | Nokia, Nokia Advanced Optical Network Management with NFM-T Course | Nokia