350-501 Automation and Quality of Services Practice Test 5 — 15 Questions

Question 1

Which DSCP value is used for voice traffic (EF) in the DiffServ model?

Accepted Answer

DSCP 46. EF (Expedited Forwarding) is assigned DSCP 46 for low-latency voice traffic.

Answer

DSCP 8

Answer

DSCP 0

Answer

DSCP 34

Question 2

Which MPLS EXP bits value is typically mapped from DSCP EF at the ingress PE to maintain voice QoS in an MPLS network?

Accepted Answer

EXP 5. DSCP EF (46) is commonly mapped to MPLS EXP 5 to preserve priority across the MPLS core.

Answer

EXP 3

Answer

EXP 7

Answer

EXP 0

Question 3

An SP is designing a QoS policy for a customer with voice, video, and data traffic. Which queuing mechanism provides a strict priority queue for voice while ensuring other queues do not starve?

Accepted Answer

LLQ. LLQ provides a strict priority queue for real-time traffic (voice) and uses CBWFQ for other data classes with bandwidth guarantees.

Answer

WFQ

Answer

WRED

Answer

CBWFQ

Question 4

In a hierarchical QoS policy applied to a subscriber aggregation interface, the parent policy shapes to 100 Mbps and the child policy allocates 50% bandwidth to voice and 50% to data. If voice traffic exceeds 50 Mbps, what happens to the excess?

Accepted Answer

Excess voice is dropped or re-marked. The child policy's police command within LLQ drops or re-marks voice traffic exceeding the configured bandwidth to prevent starvation of other queues.

Answer

Excess voice is queued in the data queue

Answer

Excess voice is shaped by the parent policy

Answer

Excess voice is forwarded with best effort

Question 5

Which protocol is used by NSO to communicate with network devices for configuration management?

Accepted Answer

NETCONF. NSO (Network Services Orchestrator) uses NETCONF as its primary protocol for configuration management because NETCONF provides a standardized, transaction-based mechanism for editing device configurations using YANG data models. This allows NSO to perform atomic, rollback-capable configuration changes across multiple network devices, which is essential for service orchestration.

Answer

gRPC

Answer

SNMP

Answer

HTTP

Question 6

An SP engineer is using YANG to model a service. Which statement correctly describes the use of a 'leafref' type?

Accepted Answer

It restricts the leaf value to match another leaf's value. Leafref references an existing leaf in the YANG data tree, ensuring consistency.

Answer

It performs data validation using XPath

Answer

It defines a new leaf with a default value

Answer

It allows multiple values to be selected

Question 7

In the context of SR-PCE, which protocol does the PCE use to communicate with the path computation client (PCC) to set up SR-TE policies?

Accepted Answer

PCEP. PCEP is the protocol used between PCE and PCC for path computation and setup.

Answer

NETCONF

Answer

OSPF

Answer

BGP-LS

Question 8

Which DSCP value corresponds to Best Effort (DF) per-hop behavior?

Accepted Answer

DSCP 0. Best Effort (DF, Default Forwarding) is DSCP 0.

Answer

DSCP 10

Answer

DSCP 8

Answer

DSCP 46

Question 9

An SP uses NSO with a YANG service model to provision L3VPNs. Which database in NSO stores the configuration and state for all managed devices?

Accepted Answer

Configuration Database (CDB). NSO's CDB (Configuration Database) holds the configuration and state of all managed devices, acting as the authoritative data store.

Answer

Operational database

Answer

YANG repository

Answer

NED database

Question 10

What is the primary difference between traffic shaping and policing in a QoS implementation?

Accepted Answer

Shaping buffers excess traffic, policing drops or re-marks. Shaping buffers excess traffic to smooth bursts, while policing drops or re-marks excess traffic to enforce a hard rate limit.

Answer

Shaping is applied at ingress, policing at egress

Answer

Shaping uses a token bucket, policing uses a leaky bucket

Answer

Shaping drops excess traffic, policing buffers it

Question 11

In a CBWFQ policy with LLQ, which statement is true regarding the bandwidth command for non-priority classes?

Accepted Answer

The sum of bandwidth for all classes must be less than 100%. The bandwidth command can specify a percentage or absolute bandwidth, but the sum must not exceed the available bandwidth (interface bandwidth minus LLQ).

Answer

The bandwidth can exceed the interface speed if shaped

Answer

Bandwidth is not used if LLQ is present

Answer

The bandwidth command is optional in CBWFQ

Question 12

Which component in MQC is used to classify traffic based on match criteria?

Accepted Answer

Class-map. In MQC, a class-map defines the match criteria to classify traffic.

Answer

Service-policy

Answer

Policy-map

Answer

Access-list

Question 13

An SP is implementing DiffServ at the edge router. Which TWO DSCP values are used for AF41 and AF31, respectively? (Choose two.)

Accepted Answer

DSCP 26. AF41 uses DSCP 34 (010001) and AF31 uses DSCP 26 (011010).

Answer

DSCP 10

Answer

DSCP 46

Answer

DSCP 18

Question 14

Which THREE statements are true regarding NSO's NED? (Choose three.)

Accepted Answer

NED can support NETCONF, SNMP, or CLI as southbound protocols. NSO's NED (Network Equipment Driver) is the component that abstracts the southbound communication between NSO and network devices. NEDs can use NETCONF, SNMP, or CLI as the southbound protocol to translate NSO's device-independent configuration into device-specific commands, enabling multi-vendor management.

Answer

NED automatically generates YANG models

Answer

NED is used for path computation in SR-TE

Question 15

Which TWO methods can RESTCONF use to create a new data resource? (Choose two.)

Accepted Answer

POST. RESTCONF uses POST to create a new resource, and PUT can also create if the resource does not exist.

Answer

PATCH

Answer

DELETE

Answer

GET