The Realest Study Materials 4A0-220 Dumps Updated Apr 26, 2024
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NEW QUESTION # 20
Which of the following parameters is not considered when restoring an LSP?
- A. Reservation priority
- B. Coloring
- C. Equipment vendor
- D. Maximum latency
Answer: C
Explanation:
Explanation
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]
NEW QUESTION # 21
A network with ROADM GMPLS nodes and optical transponder connections could have:
- A. L0 restoration capabilities
- B. L0 and LI restoration capabilities
- C. No restoration capabilities
- D. L1 restoration capabilities
Answer: B
Explanation:
Explanation
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
NEW QUESTION # 22
How can you modify the SNC Nominal Route in NFM-T?
- A. By putting the LSP in Test mode and moving traffic
- B. By using the Reroute Wizard to modify the constraints
- C. By using the Constraint Wizard to modify the constraints
- D. By changing the SRG constraints
Answer: C
Explanation:
Explanation
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
NEW QUESTION # 23
Which label is swapped in an MPLS label stack at an intermediate node?
- A. The label with the highest value
- B. The label on the bottom
- C. The label on the top
- D. The label with the lowest value
Answer: C
Explanation:
Explanation
The label on the top of the MPLS label stack is swapped at an intermediate node. This is because the top label is the one that is visible to the node and determines the forwarding decision. The node looks up the top label in its label forwarding table and swaps it with a new label that corresponds to the next hop or destination. The node then forwards the packet to the next node, which repeats the same process. The bottom label is only used to indicate the end of the label stack and is not swapped. References : [Nokia GMPLS-controlled Optical Networks Course | Nokia], [MPLS Label Stack - Nokia]
NEW QUESTION # 24
What is the Feasibility File in GMRE nodes?
- A. A file with commissioned GMRE nodes for NPA implementation
- B. A control checklist for the operator
- C. A file with target values that determine whether a given LSP can be routed
- D. A file of optical impairment parameters for power balance
Answer: C
Explanation:
Explanation
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
NEW QUESTION # 25
Automation is one of the key features of GMPLS. What is its main benefit?
- A. Reducing CAPEX
- B. Reducing OPEX
- C. Providing resilience against multiple failures
- D. Supporting multi-vendor networks
Answer: B
Explanation:
Explanation
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
NEW QUESTION # 26
In a 1830PSS MRN network, when can groups of links be combined (bundled) together in a single TE-Link?
- A. Both within layer 0 and 1 networks
- B. Only within layer 1 networks
- C. Only within layer 0 networks
- D. Never
Answer: A
Explanation:
Explanation
In a 1830PSS MRN network, groups of links can be combined (bundled) together in a single TE-Link both within layer 0 and 1 networks. A TE-Link is a logical representation of one or more physical links that share the same attributes and can be used to establish Label Switched Paths (LSPs). A TE-Link can be either single-layer or multi-layer, depending on the switching capabilities of the links. In a single-layer TE-Link, all the links belong to the same layer, either layer 0 (optical) or layer 1 (OTN). In a multi-layer TE-Link, the links belong to different layers, such as layer 0 and layer 1. A TE-Link can be either bundled or unbundled, depending on the number of links it contains. A bundled TE-Link contains more than one link, while an unbundled TE-Link contains only one link. A bundled TE-Link can provide more bandwidth and flexibility than an unbundled TE-Link. References : Nokia GMPLS-controlled Optical Networks Course | Nokia, 3.
GMPLS - Nokia
NEW QUESTION # 27
Which of the following information is present in every GMPLS-enabled node?
- A. The frequency of each client path in the entire network
- B. The state of each link in the entire network
- C. The bandwidth of each client path in the entire network
- D. The list of LSPs created in the entire network
Answer: B
Explanation:
Explanation
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
NEW QUESTION # 28
What is the Link Maintenance window?
- A. A wizard with commands to set links and nodes to maintenance
- B. A centralized alarm manager
- C. A centralized view of the TE-link for the operator
- D. A wizard for modifying TE-link attributes
Answer: A
Explanation:
Explanation
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
NEW QUESTION # 29
Which of the following statements best describes a distributed control plane for GMPLS?
- A. Each router has software to run the GMPLS protocols and can modify the node's switching fabric.
- B. The network manager controls all the routing for the network.
- C. The network is managed by more than one network management system.
- D. The control plane is active in some network nodes and not in others.
Answer: A
Explanation:
Explanation
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
NEW QUESTION # 30
When should two physical connections belong to the same SRG?
- A. When one is the protection of the other
- B. When they are both selected during the setup process
- C. When they share the same risk of failure
- D. When they are fully disjoint respective to the risk of failure
Answer: C
Explanation:
Explanation
A Shared Risk Link Group (SRLG) is a set of links sharing a common resource, which affects all links in the set if the common resource fails5. These links share the same risk of failure and are therefore considered to belong to the same SRLG. For example, links sharing a common fiber are said to be in the same SRLG because a fault with the fiber might cause all links in the group to fail. SRLGs are used in MPLS and GMPLS networks to provide traffic engineering and protection/restoration mechanisms. When computing the secondary path for an LSP, it is preferable to find a path such that the secondary and primary paths do not have any links in common in case the SRLGs for the primary and secondary paths are disjoint6. This ensures that a single point of failure on a particular link does not bring down both the primary and secondary paths in the LSP. References:
* 5: Shared risk resource group - Wikipedia
* 6: Shared Risk Link Groups for MPLS | Junos OS | Juniper Networks
NEW QUESTION # 31
What is the purpose of preemption when establishing an LSP?
- 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
Answer: C
Explanation:
Explanation
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:
* 3: RFC 4829: Label Switched Path (LSP) Preemption Policies for MPLS Traffic Engineering4
* 4: MPLS Applications User Guide | Juniper Networks5
NEW QUESTION # 32
What is the function of the OSPF-TE protocol?
- A. To assign different priority to various types of transported signals
- B. To create an MPLS tunnel between two or more end points
- C. To monitor the availability of the links interconnecting adjacent nodes
- D. To exchange with other nodes data about the state of links
Answer: D
Explanation:
Explanation
The OSPF-TE protocol is an extension of the Open Shortest Path First (OSPF) protocol that is used to exchange information about the state of links in a GMPLS network. OSPF-TE advertises link attributes such as bandwidth, latency, priority, protection, or switching capabilities to other nodes in the same area. OSPF-TE enables nodes to build a Traffic Engineering Database (TED) that contains the topology and resource information of the network. OSPF-TE helps nodes to perform CSPF calculations and establish LSPs using RSVP-TE signaling. References : Open Shortest Path First - Wikipedia, Understand Open Shortest Path First (OSPF) - Design Guide, RSVP-TE and OSPF-TE extensions for GMPLS
NEW QUESTION # 33
What does an SNC state of lower case "n" mean for a resource in NFM-T?
- A. Indicates it's currently using the Nominal resource assigned to it
- B. Indicates the nominal resource on a TE-link that is not in use
- C. Indicates it's using a link other than the Nominal
- D. Indicates if s a higher alarm state level
Answer: B
Explanation:
Explanation
The SNC state is a parameter that indicates the status of a resource in a GMPLS network. A resource can be a link, a wavelength, a timeslot, or a fiber. The SNC state can have different values, such as N, n, P, p, R, r, and so on. Each value has a specific meaning and implication for the resource and the LSP that uses it. The SNC state of lower case "n" means that the resource is the nominal resource on a TE-link that is notin use. A nominal resource is the default or preferred resource that is assigned to an LSP when it is created. A TE-link is a logical link that represents a set of resources that share the same attributes and constraints. A TE-link can have multiple resources, such as wavelengths or timeslots, but only one of them can be the nominal resource.
If an LSP is using a resource other than the nominal resource on a TE-link, it means that the LSP has been rerouted or switched due to a failure or a constraint violation. In this case, the SNC state of the nominal resource will be "n", indicating that it is not in use by any LSP12. References:
* 1: Nokia GMPLS-controlled Optical Networks Course | Nokia
* 2: Nokia Network Functions Manager for Transport User Guide | Nokia
NEW QUESTION # 34
Which provisioning steps arecommon in both CP to plain MP networks?
- A. Node creation SRG creation Node synchronization CPB power balance
- B. Node creation
CPB provisioning process Node synchronization NPA implementation - C. Node creation
CPB provisioning process Node synchronization CPB power balance - D. Node creation
CPB provisioning process Link association CPB power balance
Answer: C
Explanation:
Explanation
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
NEW QUESTION # 35
Which of the following best describes the Shutting Down state in the NFM-T?
- A. It is the same as the administrative maintenance state. No new traffic can be routed over the TE-Unk
- B. A soft maintenance state where new traffic is allowed for restoration
- C. A transient state where current SNCs are soft-rerouted
- D. An automatic shut down of all LSPs in the TE-link
Answer: C
Explanation:
Explanation
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
NEW QUESTION # 36
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