Signaling protocols are protocols that are used by the ingress router to set up a new LSP in an MPLS network. Signaling protocols are responsible for requesting, allocating, and releasing resources along the LSP, as well as establishing and maintaining the label bindings between the nodes. Some examples of signaling protocols are RSVP-TE, LDP, and CR-LDP34. References:
3: Nokia GMPLS-controlled Optical Networks Course | Nokia
4: MPLS Configuration Guide for Cisco NCS 5500 Series Routers, IOS XR Release 7.1.x - Implementing MPLS Label Distribution Protocol [Cisco IOS XR Software (End-of-Sale)] - Cisco
Questions 5
What is the purpose of the Upstream Label Object in RSVP-TE?
Options:
A.
It allows for a label to be suggested to provision bidirectional LSPs.
B.
It signals resource reservation information to upstream nodes.
C.
It allows a node to restrict the labels that may be used downstream.
The Upstream Label Object in RSVP-TE is an optional object that allows a node to suggest a label to its upstream neighbor for the purpose of provisioning bidirectional LSPs. The upstream label object is carried in the Resv message and contains the label value that the node wants to use for receiving traffic from its upstream neighbor. The upstream neighbor can accept or reject the suggested label based on its local policy and resource availability. The upstream label object simplifies the label allocation process for bidirectional LSPs and avoids the need for additional signaling messages. References : RSVP-TE - Hewlett Packard Enterprise, RSVP - Nokia
Questions 6
How can you modify the SNC Nominal Route in NFM-T?
Options:
A.
By changing the SRG constraints
B.
By using the Reroute Wizard to modify the constraints
C.
By using the Constraint Wizard to modify the constraints
D.
By putting the LSP in Test mode and moving traffic
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
Questions 7
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 8
What is the purpose of preemption when establishing an LSP?
Options:
A.
To measure the end-to-end latency
B.
To pick the next hop during LSP signalling
C.
To tear down an existing LSP in order to accommodate higher priority traffic
D.
To assign the correct wavelengths depending on the type of traffic
Preemption is a mechanism that allows a higher priority LSP to tear down an existing lower priority LSP in order to obtain the required resources for its establishment. Preemption can occur when there is not enough bandwidth or other resources available on a link or node to accommodate a new LSP request. In this case, the node can select one or more lower priority LSPs that are using the resources and send them a PathErr message with a Preempt error code. This causes the lower priority LSPs to beterminated and release their resources. The node can then allocate the resources to the higher priority LSP and send a Resv message to confirm its reservation34. References:
The GMRE functionality is guaranteed in Nokia equipment by controller redundancy. The controller is the hardware component that runs the GMPLS software and controls the switching fabric of the node. Each node has two controllers, one active and one standby, that synchronize their states and databases. If the active controller fails, the standby controller takes over and ensures the continuity of the GMRE functionality. References : Nokia GMPLS-controlled Optical Networks Course | Nokia, 1830 Photonic Service Switch (PSS) | Nokia
Questions 10
What does the SNC state with an uppercase "N" mean in a resource in NFM-T?
Options:
A.
Indicates it's using a link other than the Nominal
B.
Indicates the nominal resource on a TE-link that is not in use
C.
Indicates if s a higher alarm state level
D.
Indicates it's currently using the Nominal resource assigned to it
The SNC state with an uppercase “N” means that the resource is currently using the nominal resource assigned to it. As explained in the previous question, a nominal resource is the default or preferred resource that is assigned to an LSP when it is created. If an LSP is using the nominal resource on a TE-link, it means that the LSP has not been rerouted or switched due to any failure or constraint violation. In this case, the SNC state of the resource will be “N”, indicating that it is in use by an LSP12. References:
1: Nokia GMPLS-controlled Optical Networks Course | Nokia
2: Nokia Network Functions Manager for Transport User Guide | Nokia
Questions 11
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 12
What is the Commissioning File in GMRE nodes?
Options:
A.
A file with commissioned GMRE nodes for NPA implementation
B.
A file of optical impairment parameters for power balance
C.
A file with target values that determine whether a given LSP is possible
The Commissioning File in GMRE nodes is a file with target values that determine whether a given LSP is possible. The Commissioning File contains parameters such as power, OSNR, Q-factor, and dispersion that are used to evaluate the feasibility of an LSP request. The Commissioning File is generated by the Network Planning Application (NPA) based on the network design and optical impairments. The Commissioning File is uploaded to each GMRE node and is used by the CSPF algorithm to find a suitable path for the LSP. References : Nokia GMPLS-controlled Optical Networks Course | Nokia, Network Planning Application (NPA) | Nokia
