CCNP Practice Exam 59 — 20 Questions

Question 1

Drag and drop the steps of traffic shaping vs policing configuration steps into the correct order, from first to last.

Accepted Answer

Define class map to match traffic. Traffic shaping and policing require first defining a class map for traffic identification, then creating a policy map with either shape or police actions, applying the policy to an interface, and finally verifying the configuration. Shaping buffers excess traffic while policing drops or re-marks it.

Question 2

Drag and drop the steps of WRED configuration for TCP congestion avoidance into the correct order, from first to last.

Accepted Answer

Enable WRED globally with random-detect. WRED configuration starts by enabling the feature globally, then defining a class map for TCP traffic, creating a policy map with random-detect, applying it to an interface, and verifying the drop thresholds. WRED proactively drops packets to avoid TCP global synchronization.

Question 3

Drag and drop each DSCP value on the left to its matching Per-Hop Behavior (PHB) on the right.

Accepted Answer

DSCP 46: EF. DSCP 46 maps to EF (Expedited Forwarding), DSCP 10 maps to AF11 (Assured Forwarding class 1 low drop), DSCP 18 maps to AF21 (Assured Forwarding class 2 low drop), DSCP 26 maps to AF31 (Assured Forwarding class 3 low drop), DSCP 34 maps to AF41 (Assured Forwarding class 4 low drop).

Question 4

Drag and drop each MQC component on the left to its matching role on the right.

Accepted Answer

class-map: Defines traffic classification criteria. class-map defines traffic classification criteria, policy-map defines the QoS actions to apply, service-policy applies the policy-map to an interface, class-map uses match statements, policy-map uses class statements.

Question 5

Which two statements about policing and shaping in a QoS architecture are true? (Choose two.)

Accepted Answer

Policing can be configured on both ingress and egress interfaces, while shaping is only supported on egress interfaces.. Policing drops or re-marks traffic exceeding a rate, while shaping buffers excess traffic to smooth bursts. Policing is applied inbound or outbound, shaping is typically outbound. Policing does not introduce delay, shaping does. Both can use token bucket algorithms.

Answer

Shaping uses a token bucket algorithm to meter traffic and drops packets that exceed the configured rate.

Answer

Policing introduces variable delay because it buffers excess traffic before forwarding.

Answer

Both policing and shaping can re-mark packets that conform to the configured rate.

Question 6

Which three statements about Cisco QoS queuing and scheduling are true? (Choose three.)

Accepted Answer

Strict priority queuing ensures that voice traffic is always sent before other traffic.. Queuing manages packets when output is congested, and scheduling determines the order of transmission. Cisco uses multiple queues (e.g., 4 queues on Catalyst switches) with strict priority or weighted round-robin (WRR). Option A is correct because strict priority queue (PQ) ensures low-latency for voice. Option B is correct because WRR (or shaped round robin) is used for non-priority queues. Option C is correct because the default queue is usually queue 1 (or the best-effort queue). Option D is incorrect because tail drop is a congestion avoidance mechanism applied to a queue, not a scheduling method. Option E is incorrect because scheduling occurs on the egress interface, not ingress.

Answer

Tail drop is a scheduling algorithm that determines which queue to service next.

Answer

Queuing and scheduling are performed on the ingress interface before routing decisions.

Question 7

Drag and drop the steps of VNF scaling up and scaling out into the correct order, from first to last.

Accepted Answer

VNFM monitors metrics and detects threshold breach. Scaling begins with the VNFM monitoring performance metrics against thresholds. When a threshold is exceeded, the VNFM triggers a scaling action. For scale-up, additional resources are allocated to the existing VNF instance. For scale-out, a new VNF instance is instantiated. Finally, load balancing is updated to distribute traffic across all instances.

Question 8

Which three statements about queuing and congestion avoidance in a QoS architecture are true? (Choose three.)

Accepted Answer

Class-Based Weighted Fair Queuing (CBWFQ) assigns a weight to each class and guarantees a minimum bandwidth during congestion.. Queuing manages packets when output is congested, using algorithms like CBWFQ and LLQ. Congestion avoidance techniques like WRED proactively drop packets to prevent tail drops. LLQ provides strict priority queuing for delay-sensitive traffic. WRED can be configured per class in a policy map.

Answer

Weighted Random Early Detection (WRED) can be used only with TCP traffic and drops packets randomly based on the average queue depth.

Answer

Tail drop is a congestion avoidance mechanism that drops packets from the front of the queue when it is full.

Question 9

Which three statements about Cisco QoS policing and shaping are true? (Choose three.)

Accepted Answer

Policing can re-mark traffic that exceeds the configured rate to a lower priority.. Policing drops or re-marks traffic exceeding a rate, while shaping buffers excess traffic. Policing is typically applied inbound, shaping outbound. Option A is correct because policing can mark down traffic (e.g., set DSCP to 0) when the rate is exceeded. Option B is correct because shaping buffers traffic to smooth bursts, reducing drops. Option C is correct because both use a token bucket model to measure conformance. Option D is incorrect because policing does not buffer; it drops or re-marks. Option E is incorrect because shaping is applied on egress, not ingress.

Answer

Policing buffers traffic that exceeds the rate to reduce packet loss.

Answer

Shaping is typically applied on the ingress interface to control incoming traffic.

Question 10

Drag and drop the steps of NFV MANO (VNFM/NFVO/VIM) interaction flow into the correct order, from first to last.

Accepted Answer

NFVO receives service request from OSS/BSS. The interaction flow begins with the NFVO receiving a service request from OSS/BSS. The NFVO then requests resource allocation from the VIM. The VIM allocates resources and reports back. Next, the NFVO instructs the VNFM to instantiate the VNF. Finally, the VNFM configures and starts the VNF on the allocated resources.

Question 11

Which two statements about the Cisco QoS trust boundary are true? (Choose two.)

Accepted Answer

The trust boundary can be set at the access layer switch port connected to an IP phone.. The trust boundary defines where the device accepts or overwrites Layer 2 CoS or Layer 3 DSCP markings. By default, Cisco switches trust the CoS value on trunk ports and set DSCP to 0 on access ports. The 'mls qos trust cos' command forces the switch to trust CoS, and 'mls qos trust dscp' forces trust of DSCP. The trust boundary can be extended to an IP phone, which then re-marks traffic from the PC. Option C is incorrect because trust is not automatically applied to all interfaces; it must be configured. Option D is incorrect because the trust boundary is at the access layer, not the core. Option E is incorrect because the switch does not automatically trust DSCP from a PC; it typically sets it to 0 unless configured otherwise.

Answer

By default, all Cisco switch interfaces trust the incoming CoS or DSCP marking.

Answer

The trust boundary is always located at the distribution layer switch.

Answer

When a PC is connected to a switch port, the switch automatically trusts the DSCP value from the PC.

Question 12

Drag and drop the steps of NFVI resource allocation and VNF instantiation into the correct order, from first to last.

Accepted Answer

NFVI admin creates tenant and allocates compute/storage/network. The correct order starts with the NFVI administrator creating a tenant and allocating compute, storage, and network resources. Then the VNF descriptor is uploaded to the NFVO, which triggers the VNFM to request resource reservation. After resources are reserved, the VNFM instantiates the VNF using the allocated resources. Finally, the VNF is configured and activated to provide the intended service.

Question 13

Drag and drop the steps of Cisco NSO service provisioning workflow into the correct order, from first to last.

Accepted Answer

Operator defines service using YANG model. The Cisco NSO workflow starts with the operator defining a service in YANG model. Then NSO maps the service to device configurations using a service template. Next, NSO pushes the configuration to network devices via NETCONF. After that, NSO updates the service database with the operational state. Finally, NSO verifies the service by checking device state and alarms.

Question 14

Drag and drop the steps of service function chaining (SFC) path setup into the correct order, from first to last.

Accepted Answer

Classifier identifies traffic and adds NSH. SFC path setup starts with the classifier identifying traffic to be steered, then the classifier adds an NSH encapsulation to the packet. The first SFF receives the packet and forwards it to the first SF. After processing, the SF returns the packet to the SFF, which then forwards it to the next SFF in the chain. This repeats until the packet reaches the last SFF, which removes the NSH and forwards the packet.

Question 15

Drag and drop each VNF category on the left to its matching example on the right.

Accepted Answer

Virtual Router: Cisco CSR 1000v. VNFs replace physical appliances; common examples include virtual routers, firewalls, and load balancers.

Question 16

Which two statements about Cisco QoS classification and marking are true? (Choose two.)

Accepted Answer

A class map can match traffic based on DSCP, CoS, IP precedence, or ACL.. Classification identifies traffic based on fields like DSCP, CoS, or IP precedence. Marking sets the DSCP or CoS value for subsequent actions. The 'class-map' command matches traffic, and 'policy-map' applies marking. Option A is correct because class maps can match on DSCP, CoS, IP precedence, or even ACLs. Option B is correct because marking is typically done at the trust boundary (access layer) to set the initial QoS marking. Option C is incorrect because marking is not limited to Layer 2; Layer 3 DSCP marking is common. Option D is incorrect because marking does not use tail drop; tail drop is a congestion avoidance mechanism. Option E is incorrect because class maps do not apply actions; policy maps do.

Answer

Marking can only be applied to Layer 2 frames using CoS bits.

Answer

Marking is a congestion avoidance mechanism that uses tail drop.

Answer

A class map is used to apply marking actions to classified traffic.

Question 17

Drag and drop the steps of service function chaining (SFC) path setup into the correct order, from first to last.

Accepted Answer

Classifier identifies traffic and maps to service chain. SFC path setup begins with classifying traffic to determine which service chain to apply. Next, the classifier encapsulates packets with an NSH header. Then the SFC path is computed by the controller using the service function path identifier. After path computation, the controller installs forwarding entries in each service function forwarder. Finally, traffic traverses the chain as SFFs forward packets between VNFs.

Question 18

Drag and drop the steps of NFVI resource allocation and VNF instantiation into the correct order, from first to last.

Accepted Answer

NFVO receives VNF instantiation request. The NFVI resource allocation and VNF instantiation process begins with the NFVO receiving a VNF instantiation request, then the NFVO requests the VIM to allocate compute, storage, and network resources. The VIM allocates the resources and provides the resource IDs. The NFVO then instructs the VNFM to instantiate the VNF. Finally, the VNFM instantiates the VNF on the allocated resources.

Question 19

Drag and drop the steps of Cisco NSO service provisioning workflow into the correct order, from first to last.

Accepted Answer

Operator sends service request to NSO. Cisco NSO service provisioning begins with the operator or OSS sending a service request to NSO via NETCONF/RESTCONF. NSO then processes the service model and creates a service instance. NSO uses device templates and YANG models to generate device configurations. NSO pushes the configuration to the network devices using NETCONF. Finally, NSO verifies the service is operational and updates the service state.

Question 20

Drag and drop each hypervisor type on the left to its matching characteristic on the right.

Accepted Answer

Type 1 hypervisor: Runs directly on physical hardware without a host OS. Type 1 hypervisors run directly on hardware and are common in data centers; Type 2 run on a host OS and are used for desktop virtualization.