A Label Switched Path (LSP) is the path created by MPLS nodes that use labels to forward packets across the network. A label is a short identifier that is attached to each packet and indicates the next hop or destination of the packet. The nodes use a label forwarding table to switch packets based on their labels, without inspecting the packet headers. This can improve the performance, security, and quality of service of the network. An LSP can be established by using GMPLS protocols such as OSPF-TE and RSVP-TE, which exchange information about the network topology, resources, and constraints. References : Nokia GMPLS-controlled Optical Networks Course | Nokia, GMPLS - Nokia
Questions 5
Which of the following best describes the Shutting Down state in the NFM-T?
Options:
A.
An automatic shut down of all LSPs in the TE-link
B.
A soft maintenance state where new traffic is allowed for restoration
C.
It is the same as the administrative maintenance state. No new traffic can be routed over the TE-Unk
D.
A transient state where current SNCs are soft-rerouted
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
Questions 6
Which of the following statements best describes a distributed control plane for GMPLS?
Options:
A.
The control plane is active in some network nodes and not in others.
B.
Each router has software to run the GMPLS protocols and can modify the node's switching fabric.
C.
The network manager controls all the routing for the network.
D.
The network is managed by more than one network management system.
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
Questions 7
What is the Link Maintenance window?
Options:
A.
A centralized view of the TE-link for the operator
B.
A wizard with commands to set links and nodes to maintenance
The Link Maintenance window is a feature of NFM-T that allows the user to perform maintenance tasks on links and nodes in a GMPLS network. The Link Maintenance window is a wizard that provides commands to set links and nodes to maintenance mode, which prevents them from being used for routing new LSPs or carrying traffic. The user can also use the Link Maintenance window to reroute existing LSPs away from the links and nodes that are in maintenance mode, either manually or automatically. The Link Maintenance window helps the user to perform network maintenance operations without disrupting the service availability or quality12. References:
1: Nokia GMPLS-controlled Optical Networks Course | Nokia
2: Nokia Network Functions Manager for Transport User Guide | Nokia
Questions 8
What is Tunnel Property Heritage?
Options:
A.
The hierarchy tunnels cannot be nested unless they share the same properties.
B.
Maximum allowed bandwith is propagated from HO to LO LSPs.
C.
A restored tunnel inherits the ODUk flows.
D.
Cost, SRLG, and Color properties are propagated from HO to LO LSPs.
Tunnel Property Heritage is a feature of GMRE that allows the propagation of certain properties from higher order (HO) LSPs to lower order (LO) LSPs in a multi-layer network. These properties include cost, SRLG, and color. Cost is a metric that reflects the preference of using a certain link or path for routing. SRLG is a set of links that share a common risk of failure. Color is an attribute that can be used to group or filter LSPs based on service classes or customer profiles. By propagating these properties from HO to LO LSPs, GMRE can ensure that the end-to-end LSPs are consistent and optimal across different layers34. References:
3: Nokia GMPLS-controlled Optical Networks Course | Nokia
4: GMPLS - Nokia
Questions 9
How do you add a 3R resource to the NPA in NFM-T?
Options:
A.
The 3R is added in the Node panel and automatically added to the NPA
B.
The 3R is added to the NPA through the Constraint Wizard
C.
The resource is discovered automatically
D.
The trail is provisioned with 3R constraints and discovered automatically
The 3R resource is a type of optical regeneration resource that can be used to extend the reach of optical signals in a GMPLS-controlled optical network. The 3R resource performs three functions: reshaping, retiming, and reamplifying the optical signal. The 3R resource can be added to the Network Planning Application (NPA) in the Nokia Network Functions Manager for Transport (NFM-T) through the Constraint Wizard. The Constraint Wizard is a tool that allows the user to define various constraints and parameters for the network design, such as optical impairments, wavelength availability, protection schemes, and regeneration resources. The user can select the 3R resource from the list of available resources and specify its location, capacity, and cost. The NPA then uses this information to perform feasibility checks and path computation for the LSP requests12. References:
1: Nokia GMPLS-controlled Optical Networks Course | Nokia
2: Nokia Network Functions Manager for Transport User Guide | Nokia
Questions 10
Which of the following is not a key feature of GMPLS?
GMPLS is a protocol suite that extends the MPLS signaling and routing capabilities to control different types of switching technologies, such as optical, TDM, and packet switching1. GMPLS has several key features, such as self-discovery, fast protection, and restoration. Self-discovery allows GMPLS nodes to automatically discover their neighbors and exchange information about their capabilities and resources2. Fast protection enables GMPLS nodes to quickly switch to backup paths in case of a failure, without relying on the control plane3. Restoration allows GMPLS nodes to dynamically establish new paths in the network after a failure, using the control plane3. Resource optimization is not a key feature of GMPLS, but rather a potential benefit of using GMPLS to efficiently utilize the network resources and avoid over-provisioning. 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
Questions 11
Which of the following parameters is not considered when restoring an LSP?
The equipment vendor is not a parameter that is considered when restoring an LSP. Restoration is the process of re-establishing an LSP after a failure by using an alternative path that meets the same constraints as the original LSP. The parameters that are considered when restoring an LSP include coloring, reservation priority, maximum latency, bandwidth, protection type, and other QoS attributes. The equipment vendor does not affect the restoration process as long as the nodes support GMPLS protocols and interoperate with each other. References : RFC 4427 - Recovery (Protection and Restoration) Terminology for Generalized Multi-Protocol Label Switching (GMPLS), [Nokia GMPLS-controlled Optical Networks Course | Nokia]
Questions 12
Automation is one of the key features of GMPLS. What is its main benefit?
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
