JNCIA-DevOps NETCONF And XML API Practice Test 5 — 15 Questions

Question 1

An engineer applies a configuration change using NETCONF with <edit-config> and specifies default-operation="replace" at the top level, but includes an element with operation="merge". How does Junos evaluate this?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

The specific element operation ('merge') takes precedence over the transaction-level default-operation ('replace').. Per-element operation attributes override the default-operation specified at the transaction level.

Answer

The transaction fails because default-operation and element operations conflict.

Answer

The device rolls back the configuration due to ambiguous parameters.

Answer

The default-operation takes precedence, ignoring the merge attribute.

Question 2

Which python module is part of the standard library that can be used to parse XML responses returned by NETCONF?

Accepted Answer

xml.etree.ElementTree. Python's built-in xml.etree.ElementTree module provides tools for parsing and navigating XML data.

Answer

netconf.parser

Answer

xml2dict

Answer

json

Question 3

Which TWO actions occur during the initial NETCONF session establishment phase between a client and a Junos device? (Choose two)

Accepted Answer

The client and server exchange messages to negotiate supported capabilities.. Option A is correct because NETCONF session establishment begins with both peers exchanging messages that advertise their capabilities and, in the server's case, the session-id, allowing the client and Junos device to negotiate supported features such as candidate configuration or confirmed commit. Option D is correct because NETCONF runs over SSH on Junos (typically TCP port 830), so the client must complete SSH authentication before the NETCONF subsystem is started and the exchange can occur. Option B is wrong because a RPC is a configuration operation performed after the session is established, not part of session initialization. Option C is wrong because NETCONF session setup does not reload or restart routing engine control-plane daemons. Option E is wrong because the running configuration datastore is not automatically locked during session establishment; locking is an explicit client action via the RPC.

Answer

The client sends an immediate <commit> RPC to initialize the session.

Answer

The routing engine reloads its control plane daemons.

Answer

The Junos device automatically locks the running configuration datastore.

Question 4

Which THREE error-type values are defined in the NETCONF protocol specification (RFC 6241) for categorizing <rpc-error> messages? (Choose three)

Accepted Answer

rpc. RFC 6241 defines the element of an with exactly three enumerated values: rpc (A), transport (C), and protocol (D). The rpc value indicates an error occurred during RPC processing on the server, such as an invalid or malformed RPC element. The transport value indicates an error at the transport-protocol layer, such as a dropped connection or authentication failure. The protocol value indicates a violation of the NETCONF protocol semantics, such as an unknown operation or missing mandatory parameter. The unmarked options hardware (B) and kernel (E) are not part of the RFC 6241 enumeration; they resemble syslog or SNMP-style categories and have no defined role in NETCONF error reporting.

Answer

hardware

Answer

kernel

Question 5

Which THREE distinct operational states or configuration views can be queried using specific Junos XML API RPCs? (Choose three)

Accepted Answer

System information via . Option A is correct because the Junos XML API provides the RPC, which returns operational system data such as hostname, uptime, and platform details from the device. Option C is correct because is a valid Junos RPC that queries the hardware inventory of the chassis, including components like FPCs, PICs, and power supplies. Option E is correct because is a standard Junos RPC used to retrieve operational state and statistics for interfaces, equivalent to the CLI 'show interfaces' command. Option B is not correct because there is no Junos XML API RPC named ; BGP routing information is retrieved through other RPCs such as or . Option D is not correct because is not a valid Junos RPC for retrieving firewall filter logs; packet capture and log retrieval use different mechanisms and commands.

Answer

BGP routing table via <get-bgp-kernel-table>

Answer

Firewall filter logs via <get-security-packet-capture>

Question 6

Which TWO statements are true regarding NETCONF locking mechanisms on Junos devices? (Choose two)

Accepted Answer

If a NETCONF session terminates unexpectedly, any locks held by that session are automatically released by the device.. Option A is correct because Junos ties NETCONF locks to the session that acquired them; if the session drops or terminates abnormally, the device automatically releases those locks so the configuration is not left permanently locked. Option C is correct because locking the candidate datastore grants exclusive write access, blocking other users or automation scripts from committing conflicting changes until the lock is released. Option B is incorrect because the candidate datastore lock is exclusive, so only one session can hold it at a time. Option D is incorrect because locks are released through normal NETCONF operations such as or session termination, not by rebooting the Routing Engine. Option E is incorrect because locking is not required for read-only requests; it is used to protect configuration changes.

Answer

Multiple concurrent NETCONF sessions can obtain exclusive write locks on the candidate datastore at the same time.

Answer

Locks can only be released by rebooting the Routing Engine.

Answer

Locking is strictly mandatory for every single <get-config> request.

Question 7

Which THREE error-tag values defined in NETCONF RFC 6241 may be returned by a Junos device when an edit-config operation fails validation? (Choose three)

Accepted Answer

invalid-value. Option B, invalid-value, is correct because RFC 6241 defines this error-tag for when a configuration value is syntactically or semantically invalid, which is exactly what a Junos device reports when edit-config content fails validation checks such as range or type constraints. Option C, data-exists, is correct because it is the standard NETCONF error-tag returned when a create operation targets data that already exists, a common validation failure during edit-config processing. Option E, missing-element, is correct because RFC 6241 specifies this tag for when a required element is absent from the configuration being edited, another typical validation error. Option A, syntax-timeout, is not a defined NETCONF error-tag in RFC 6241, and option D, buffer-overflow, is likewise not part of the RFC 6241 error-tag enumeration, so neither belongs.

Answer

syntax-timeout

Answer

buffer-overflow

Question 8

Which TWO benefits does NETCONF provide over traditional screen-scraping CLI automation? (Choose two)

Accepted Answer

Structured data representation (XML) that eliminates the need for complex regular expression parsing.. Option A is correct because NETCONF encodes configuration and state data in structured XML (per RFC 6241), so management applications can consume well-defined elements and namespaces instead of brittle screen-scraping with regular expressions against human-oriented CLI output. Option D is correct because NETCONF defines formal RPC transaction semantics, including candidate datastores, commit/rollback operations, and standardized error reporting via <rpc-error> elements, which CLI scraping cannot guarantee. Option B is wrong because NETCONF is a configuration protocol and does not generate physical fiber cabling diagrams. Option C is wrong because NETCONF still requires authentication (commonly SSH per RFC 6242), so it does not eliminate credentials. Option E is wrong because NETCONF does not compress payloads into binary audio streams or reduce bandwidth requirements in that manner.

Answer

Automatic generation of physical fiber cabling diagrams.

Answer

Elimination of any need for authentication credentials.

Answer

Requirement for lower bandwidth links by compressing all payloads into binary audio streams.

Question 9

Which TWO methods can an administrator use to verify that a Python script successfully established a NETCONF session with a Junos device? (Choose two)

Accepted Answer

Run 'show system netconf sessions' on the Junos CLI.. Option B is correct because the Junos CLI command 'show system netconf sessions' displays active NETCONF-over-SSH sessions on the device, including the session ID, client, and login time, directly confirming that the script's NETCONF session was established. Option D is correct because a PyEZ or ncclient-based script can programmatically confirm success via return objects (for example, a connected Device instance or a successful <hello> exchange) and by inspecting execution logs that record session establishment or exceptions. Option A is wrong because BGP neighbor adjacency tables reflect routing protocol state, not NETCONF session status. Option C is wrong because physical interface link LEDs only indicate Layer 1 link state and say nothing about an application-layer NETCONF session. Option E is wrong because temperature sensors report hardware environmental data unrelated to NETCONF connectivity.

Answer

Review BGP neighbor adjacency tables.

Answer

Verify physical interface link LEDs.

Answer

Check the device temperature sensors.

Question 10

A network engineer is establishing a NETCONF session with a Junos device and needs to lock the candidate configuration to prevent concurrent modifications by other administrators. Which NETCONF operation should be executed?

Accepted Answer

. The operation allows a client to lock the configuration datastore of a device to prevent unauthorized or conflicting changes during a transaction.

Answer

<lock-config><database>candidate</database></lock-config>

Answer

<get-config><source><candidate/></source><lock/></get-config>

Answer

<edit-config><target><candidate/></target><operation>lock</operation></edit-config>

Question 11

Which THREE attributes are available within the <edit-config> operation element in NETCONF to specify the modification action on a target node? (Choose three)

Accepted Answer

delete. The NETCONF <edit-config> operation supports the operation attribute, whose valid values are merge, replace, create, delete, and remove. Option A (delete) is correct because the delete operation attribute removes a node that exists in the target datastore, and it is one of the standard values defined in RFC 6241. Option B (replace) is correct because replace overwrites the target node's value or configuration with the supplied content, creating it if it does not exist. Option E (merge) is correct because merge is the default operation attribute value, combining the supplied configuration with the existing target datastore content. Option C (append) is not a valid NETCONF operation attribute value; list/leaf-list additions are handled via merge or the insert/key attributes. Option D (modify) is not a defined operation attribute value in NETCONF; modification is achieved through merge, replace, create, delete, or remove.

Answer

append

Answer

modify

Question 12

Which transport protocol is mandated by RFC 6241 as the standard secure connection mechanism for NETCONF when operating in typical Junos enterprise automation environments?

Accepted Answer

SSH. RFC 6241 specifies NETCONF over Secure Shell (SSH) as the standard secure transport protocol.

Answer

HTTPS

Answer

gRPC

Answer

TLS

Question 13

An engineer writes a Python script using ncclient to push changes to a Junos device. After sending the configuration via <edit-config>, the script needs to make the changes active without dropping the NETCONF session lock prematurely or requiring a separate explicit commit RPC if candidate workflows are bypassed. However, using standard candidate datastore workflow, what is the exact RPC required to activate the candidate configuration?

Accepted Answer

. The RPC is used to commit the candidate configuration to the running configuration datastore in Junos.

Answer

<apply-changes/>

Answer

<save-config/>

Answer

<push-running/>

Question 14

Which TWO statements are true regarding the NETCONF protocol hello message exchange? (Choose two.)

Accepted Answer

Both client and server exchange capabilities using XML elements containing URI strings.. Option C is correct because in the NETCONF hello exchange both peers send a element containing a list, where each capability is expressed as a URI string (for example urn:ietf:params:netconf:base:1.0 or urn:ietf:params:netconf:capability:candidate:1.0), allowing each side to learn the other's supported features. Option D is correct because the server's hello includes a element, a positive integer attribute that uniquely identifies the NETCONF session for the duration of that connection. Option A is wrong because database locking is performed later with operations, not during the hello exchange, and the hello occurs before any configuration operations. Option B is wrong because the client hello advertises supported capabilities, not a list of YANG modules it intends to modify. Option E is wrong because the hello exchange is mandatory in NETCONF regardless of the SSH authentication method used.

Answer

The client uses the hello message to lock the configuration database before session initialization.

Answer

The client hello message must include the list of YANG modules it intends to modify during the session.

Answer

The hello message exchange is optional if a pre-shared SSH key is used for authentication.

Question 15

A network automation engineer is establishing a NETCONF session with a Junos device. After the SSH connection is established, the device and the client exchange <hello> messages. What is the primary purpose of this exchange?

Accepted Answer

To negotiate NETCONF capabilities and session parameters.. The <hello> messages are exchanged immediately after the SSH connection to advertise and negotiate NETCONF capabilities. This includes the base protocol version, supported datastores, and other features. It ensures that both the client and server understand what operations are available before any RPCs are sent. It does not authenticate, synchronize clocks, or transfer configuration.

Answer

To synchronize the device's clock with the client's clock.

Answer

To authenticate the client and establish a secure channel.

Answer

To transfer the initial configuration from the device to the client.