JNCIA-DevOps NETCONF And XML API — 20 Questions

Question 1

Which TWO attributes or parameters can be used within a NETCONF <edit-config> operation to control how configuration data is merged or replaced? (Choose two)

Accepted Answer

target. The <edit-config> RPC accepts parameters such as target, default-operation, and test-option.

Answer

baud-rate

Answer

ssh-cipher

Question 2

Which TWO elements are mandatory components of every valid NETCONF RPC request sent to a Junos device? (Choose two)

Accepted Answer

Appropriate XML namespace definitions (xmlns). Every NETCONF request must be enclosed in an <rpc> XML element and possess a valid namespace.

Answer

Answer

<lock>

Question 3

Which NETCONF RPC tag is used to gracefully terminate an active NETCONF session with a Junos device?

Accepted Answer

. The RPC requests graceful termination of the NETCONF session.

Answer

<terminate-session>

Answer

Answer

<kill-session>

Question 4

While executing a NETCONF edit-config operation, you want to ensure that any syntax errors or invalid statements immediately cause the device to roll back the entire transaction without applying partial changes. Which parameter achieves this?

Accepted Answer

rollback-on-error. The error-option element with the value 'rollback-on-error' instructs the device to abort and roll back if any error occurs.

Answer

test-then-set

Answer

<default-operation>none</default-operation>

Answer

stop-on-error

Question 5

Which XML tag encapsulates the entire response returned by a Junos device in reply to a valid NETCONF RPC request?

Accepted Answer

. Every NETCONF response from a Junos device is wrapped in an tag.

Answer

<response-data>

Answer

<xml-reply>

Answer

<netconf-response>

Question 6

You want to retrieve only the system hostname from the Junos running configuration using NETCONF. Which filtering technique is most efficient?

Accepted Answer

Subtree filtering using XML element tags matching the configuration hierarchy. Tag-based filtering allows requesting specific configuration hierarchies by including empty container tags in the <get-config> request.

Answer

XPath expression filtering via the select attribute

Answer

Regular expression pattern matching within the <filter> attribute

Answer

Retrieving the entire configuration and parsing it locally with a Python script

Question 7

You need to lock the candidate configuration datastore in your NETCONF script to prevent concurrent modifications by other administrators. Which XML element accomplishes this?

Accepted Answer

. The RPC takes a target element specifying which datastore to lock, such as the candidate datastore.

Answer

<lock-config>

Answer

<acquire-lock>

Answer

<exclusive-edit>

Question 8

You are writing a Python script to retrieve the operational state of interfaces from a Junos device using NETCONF. Which XML RPC element must be enclosed within the <rpc> tag to request operational data?

Accepted Answer

. The rpc tag is used to retrieve both configuration and operational data, whereas is restricted to configuration data.

Answer

<pull-operational>

Answer

<get-rpc-reply>

Answer

<get-config>

Question 9

An administrator issues an edit-config RPC with default-operation="replace" targeting the candidate datastore. What is the impact on the existing configuration on the Junos device?

Accepted Answer

The entire target configuration datastore is replaced by the configuration provided in the RPC payload.. The replace operation overwrites the entire target configuration datastore with the configuration provided in the RPC message.

Answer

The configuration is merged, and any conflicting nodes generate a validation error.

Answer

The candidate datastore is cleared, and only the default factory configuration is loaded.

Answer

Only the specific leaf nodes provided in the RPC are updated; everything else remains intact.

Question 10

An engineer needs to establish a NETCONF session with a Junos device securely. Which underlying transport protocol does NETCONF use by default according to RFC 6242?

Accepted Answer

TCP port 830. NETCONF over SSH is defined in RFC 6242 and uses TCP port 830 by default for secure transport.

Answer

TCP port 22

Answer

TCP port 443

Answer

UDP port 830

Question 11

An engineer executes a NETCONF <discard-changes> RPC. What is the precise effect of this operation on the Junos device?

Accepted Answer

It discards all uncommitted changes currently sitting in the candidate datastore, reverting it to match the running datastore.. The <discard-changes> RPC discards any uncommitted changes present in the candidate configuration datastore.

Answer

It clears all active alarms and operational logs from the routing engine.

Answer

It terminates all active NETCONF sessions currently connected to the device.

Answer

It reverts the active running configuration to the factory default state.

Question 12

An automation script attempts to load a configuration snippet using NETCONF <edit-config> with operation="delete" on a container statement. What happens if the specified container does not currently exist in the candidate configuration?

Accepted Answer

The device returns a NETCONF rpc-error indicating the node does not exist.. The delete operation fails if the target node does not exist, whereas remove is silent if absent.

Answer

The device ignores the request and returns an OK response.

Answer

The device converts the operation to a merge automatically.

Answer

The device automatically creates the container as an empty object.

Question 13

You need to commit a candidate configuration change on a Junos device via NETCONF with a confirmed commit timeout of 5 minutes. Which XML payload structure is correct?

Accepted Answer

5

. The RPC accepts a tag and a element to specify rollback timing.

Answer

Answer

Answer

Question 14

When establishing a NETCONF session over SSH, which standard capability announcement is exchanged during the initial hello message phase?

Accepted Answer

urn:ietf:params:netconf:base:1.0. NETCONF capabilities are exchanged in <hello> messages at session startup, referencing URIs like urn:ietf:params:netconf:base:1.0.

Answer

http://xml.juniper.net/junos/rpc/v1

Answer

netconf:params:xml:ns:netconf:base:2.0

Answer

urn:juniper:params:netconf:ssh:1.0

Question 15

You are troubleshooting a NETCONF session where the client sent an improperly formatted XML payload. Where would you expect to find detailed error logging related to this malformed XML request on the Junos device?

Accepted Answer

NETCONF traceoptions output file or /var/log/messages. Junos logs NETCONF and XML API activity, including parsing errors, into the traceoptions log file if configured, or general system logs.

Answer

/var/log/netconf.log

Answer

/var/db/config/juniper.conf.gz

Answer

/etc/netconf/errors.xml

Question 16

Which command or tool on a Junos device verifies that the NETCONF subsystem is enabled and listening for SSH connections?

Accepted Answer

show system services netconf ssh. NETCONF over SSH runs as a subsystem on Junos and can be verified via system services configuration or operational commands.

Answer

show netconf settings

Answer

show xml-api status

Answer

show netconf status connections

Question 17

When executing a NETCONF request, you specify but omit any filtering tags. What is returned in the ?

Accepted Answer

The complete configuration contained within the candidate datastore.. Omiting filter tags on a <get-config> request returns the entire contents of the specified configuration datastore.

Answer

An rpc-error stating that a filter is mandatory.

Answer

Only the differences between candidate and running configurations.

Answer

Only the top-level system hierarchy statements.

Question 18

In Junos XML API, what is the XML namespace associated with Junos-specific RPCs and operational tags?

Accepted Answer

http://xml.juniper.net/junos/*/junos-rpc. Junos XML API elements use specific namespaces like http://xml.juniper.net/junos/12.1X46/junos-sw for software or general rpc namespaces.

Answer

http://www.cisco.com/ns/yang/cisco-se

Answer

urn:juniper:params:xml:ns:netconf:base:1.0

Answer

urn:ietf:params:xml:ns:netconf:base:1.0

Question 19

Which tool or library is commonly used in Python to simplify interacting with Junos NETCONF APIs by abstracting low-level XML handling?

Accepted Answer

Junos PyEZ (juniper-eznc). PyEZ is Juniper's official Python library designed specifically for interacting with Junos devices via NETCONF.

Answer

Netmiko

Answer

Paramiko

Answer

Requests

Question 20

You need to load a set of configuration changes into the Junos candidate datastore from an inline XML string using NETCONF. Which RPC element is used to load configuration data?

Accepted Answer

. The RPC is a Juniper-specific extension used within NETCONF to load configuration data with formats like XML, text, or set.

Answer

<update-candidate>

Answer

<set-config>

Answer

<edit-config>