JUNIPER NETWORKS CERTIFIED ASSOCIATE (JNCIA-JUNOS) EXAM
PRACTICE QUESTIONS AND CORRECT ANSWERS (VERIFIED ANSWERS)
PLUS RATIONALES Q&A INSTANT DOWNLOAD PDF
140 QUESTIONS
TABLE OF CONTENTS
# TOPIC
1 Analyze Junos OS architecture and packet flow to diagnose complex network issues
2 Design and implement routing policies, firewall filters, and class-of-service configurations
3 Evaluate and configure Junos security features including zones, NAT, and IPsec
4 Apply automation and scripting techniques using Junos XML API and PyEZ
5 Compare and contrast Junos operational and configuration modes for effective network management
6 Juniper Networks Certified Associate
7 JNCIA
8 Junos
9 Exam Practice Questions And Correct Answers
10 Verified Answers
11 Plus Rationales Q&A Instant Download Pdf
12 Foundations of Juniper Networks Certified Associate (JNCIA-Junos)
13 Applied Juniper Networks Certified Associate (JNCIA-Junos)
14 Advanced Juniper Networks Certified Associate (JNCIA-Junos)
15 Juniper Networks Certified Associate (JNCIA-Junos) Review
Page 1
,Q1 ANALYZE JUNOS OS ARCHITECTURE AND PACKET FLOW TO DIAGNOSE COMPLEX
NETWORK ISSUES
In Junos OS, which architectural component is responsible for maintaining the
routing table and generating the forwarding table, and what is the primary
mechanism for communication between this component and the Packet
Forwarding Engine?
A. Routing Engine; ASIC-based high-speed data bus
B. Control Board; internal Ethernet link using IPv6
C. Routing Engine; internal link using a proprietary protocol CORRECT
D. Forwarding Engine; shared memory interface
RATIONALE: Junos separates control and forwarding planes. The Routing Engine (RE)
maintains routing tables and computes the forwarding table, communicating with the Packet
Forwarding Engine (PFE) via an internal link using a proprietary protocol (e.g., the Juniper
proprietary protocol over a dedicated internal Ethernet or high-speed link). ASICs are in the PFE,
not the communication mechanism. The Control Board is a component of the RE in some
platforms, not the main communicator. The Forwarding Engine is the PFE itself, not a separate
component.
Q2 ANALYZE JUNOS OS ARCHITECTURE AND PACKET FLOW TO DIAGNOSE COMPLEX
NETWORK ISSUES
You are configuring a new Junos device and need to ensure that when a
configuration commit fails, the device automatically reverts to the last good
configuration. Which configuration group or operational command would you use
to achieve this behavior, and what is the correct syntax?
A. set system commit synchronize
B. set system commit confirm 10 CORRECT
C. set system rollback 1
D. set system configuration-revert
RATIONALE: The 'commit confirm' feature allows a configuration to be automatically rolled back
if the commit is not confirmed within the specified time (in minutes). This is used to prevent
lockout. 'commit synchronize' is for multi-RE systems to commit on both REs. 'rollback' is a
command to revert to a previous configuration, not automatic on failure. 'configuration-revert' is
not a valid Junos command.
Page 2
,Q3 ANALYZE JUNOS OS ARCHITECTURE AND PACKET FLOW TO DIAGNOSE COMPLEX
NETWORK ISSUES
In Junos, when configuring a firewall filter, you apply it to an interface. Which of
the following statements correctly describes the order of evaluation and the
default action if no term matches?
A. Terms are evaluated in order, and the first match is executed; if no term matches, the packet
is discarded.
B. Terms are evaluated in reverse order, and the last match is executed; if no term matches, the
packet is accepted.
C. Terms are evaluated in order, and all matching terms are executed; if no term matches, the
packet is accepted.
D. Terms are evaluated in order, and the first match is executed; if no term matches, the packet
is accepted. CORRECT
RATIONALE: Junos firewall filters evaluate terms in order, and the first term with a match
executes its action; subsequent terms are not evaluated. If no term matches, the default action is
to accept the packet (for filters applied in the input direction). This is opposite to some other
vendors. The other options are incorrect because terms are not evaluated in reverse, not all
matching terms are executed, and the default is not discard.
Q4 ANALYZE JUNOS OS ARCHITECTURE AND PACKET FLOW TO DIAGNOSE COMPLEX
NETWORK ISSUES
You are tasked with configuring a class-of-service (CoS) policy to ensure that
voice traffic (EF) experiences lower latency and jitter than bulk data (BE). Which
CoS components must be configured to achieve this, and what is the correct
sequence of operations?
A. Classifiers, schedulers, and rewrite rules; applied in that order. CORRECT
B. Schedulers, classifiers, and drop profiles; applied in that order.
C. Classifiers, drop profiles, and schedulers; applied in any order.
D. Drop profiles, schedulers, and classifiers; applied in that order.
RATIONALE: CoS architecture requires classifiers to assign packets to forwarding classes,
schedulers to prioritize transmission, and rewrite rules to set the output packet headers. The
order is classifiers, then schedulers, then rewrite rules. Drop profiles are part of schedulers, not a
separate top-level component. The other options have incorrect order or components.
Page 3
, Q5 ANALYZE JUNOS OS ARCHITECTURE AND PACKET FLOW TO DIAGNOSE COMPLEX
NETWORK ISSUES
In Junos, which routing protocol uses the concept of 'active route' and 'backup
route' to populate the routing table, and how does Junos handle multiple routes to
the same destination from different protocols?
A. OSPF; uses administrative distance to select the active route.
B. BGP; uses local preference and AS path length to select the active route.
C. All protocols; Junos uses route preference (administrative distance) to select the active route
and keeps all others as backups. CORRECT
D. IS-IS; uses metric to select the active route and discards others.
RATIONALE: Junos maintains a single active route per destination in the forwarding table,
chosen by the lowest route preference (administrative distance) among all protocols. Other
routes are kept as backup routes in the routing table but not installed in the forwarding table
unless the active route fails. This applies to all protocols, not just OSPF or BGP. Route
preference is a Junos-specific term for administrative distance.
Q6 ANALYZE JUNOS OS ARCHITECTURE AND PACKET FLOW TO DIAGNOSE COMPLEX
NETWORK ISSUES
An engineer needs to automate configuration of multiple Junos devices. They
decide to use Junos PyEZ to push configuration changes. Which of the following
best describes the correct usage of PyEZ to load and commit a configuration from
a file?
A. Use the 'load' method with 'path' argument to load the file, then call 'commit' on the device.
B. Use the 'load_config' method with 'path' and 'merge' parameters, then call 'commit' on the
device. CORRECT
C. Use the 'open' method to read the file, then use 'configure' to apply changes, then 'commit'.
D. Use the 'send' method to execute CLI commands to load and commit the configuration.
RATIONALE: PyEZ provides the 'load_config' method on a Device instance to load configuration
from a file or string, with options like 'merge' or 'replace'. After loading, you call 'commit' to apply.
The 'load' method is not a PyEZ method; it's a CLI command. 'open' is used to connect, not to
load config. 'send' is for executing CLI commands, not for loading config files.
Page 4
PRACTICE QUESTIONS AND CORRECT ANSWERS (VERIFIED ANSWERS)
PLUS RATIONALES Q&A INSTANT DOWNLOAD PDF
140 QUESTIONS
TABLE OF CONTENTS
# TOPIC
1 Analyze Junos OS architecture and packet flow to diagnose complex network issues
2 Design and implement routing policies, firewall filters, and class-of-service configurations
3 Evaluate and configure Junos security features including zones, NAT, and IPsec
4 Apply automation and scripting techniques using Junos XML API and PyEZ
5 Compare and contrast Junos operational and configuration modes for effective network management
6 Juniper Networks Certified Associate
7 JNCIA
8 Junos
9 Exam Practice Questions And Correct Answers
10 Verified Answers
11 Plus Rationales Q&A Instant Download Pdf
12 Foundations of Juniper Networks Certified Associate (JNCIA-Junos)
13 Applied Juniper Networks Certified Associate (JNCIA-Junos)
14 Advanced Juniper Networks Certified Associate (JNCIA-Junos)
15 Juniper Networks Certified Associate (JNCIA-Junos) Review
Page 1
,Q1 ANALYZE JUNOS OS ARCHITECTURE AND PACKET FLOW TO DIAGNOSE COMPLEX
NETWORK ISSUES
In Junos OS, which architectural component is responsible for maintaining the
routing table and generating the forwarding table, and what is the primary
mechanism for communication between this component and the Packet
Forwarding Engine?
A. Routing Engine; ASIC-based high-speed data bus
B. Control Board; internal Ethernet link using IPv6
C. Routing Engine; internal link using a proprietary protocol CORRECT
D. Forwarding Engine; shared memory interface
RATIONALE: Junos separates control and forwarding planes. The Routing Engine (RE)
maintains routing tables and computes the forwarding table, communicating with the Packet
Forwarding Engine (PFE) via an internal link using a proprietary protocol (e.g., the Juniper
proprietary protocol over a dedicated internal Ethernet or high-speed link). ASICs are in the PFE,
not the communication mechanism. The Control Board is a component of the RE in some
platforms, not the main communicator. The Forwarding Engine is the PFE itself, not a separate
component.
Q2 ANALYZE JUNOS OS ARCHITECTURE AND PACKET FLOW TO DIAGNOSE COMPLEX
NETWORK ISSUES
You are configuring a new Junos device and need to ensure that when a
configuration commit fails, the device automatically reverts to the last good
configuration. Which configuration group or operational command would you use
to achieve this behavior, and what is the correct syntax?
A. set system commit synchronize
B. set system commit confirm 10 CORRECT
C. set system rollback 1
D. set system configuration-revert
RATIONALE: The 'commit confirm' feature allows a configuration to be automatically rolled back
if the commit is not confirmed within the specified time (in minutes). This is used to prevent
lockout. 'commit synchronize' is for multi-RE systems to commit on both REs. 'rollback' is a
command to revert to a previous configuration, not automatic on failure. 'configuration-revert' is
not a valid Junos command.
Page 2
,Q3 ANALYZE JUNOS OS ARCHITECTURE AND PACKET FLOW TO DIAGNOSE COMPLEX
NETWORK ISSUES
In Junos, when configuring a firewall filter, you apply it to an interface. Which of
the following statements correctly describes the order of evaluation and the
default action if no term matches?
A. Terms are evaluated in order, and the first match is executed; if no term matches, the packet
is discarded.
B. Terms are evaluated in reverse order, and the last match is executed; if no term matches, the
packet is accepted.
C. Terms are evaluated in order, and all matching terms are executed; if no term matches, the
packet is accepted.
D. Terms are evaluated in order, and the first match is executed; if no term matches, the packet
is accepted. CORRECT
RATIONALE: Junos firewall filters evaluate terms in order, and the first term with a match
executes its action; subsequent terms are not evaluated. If no term matches, the default action is
to accept the packet (for filters applied in the input direction). This is opposite to some other
vendors. The other options are incorrect because terms are not evaluated in reverse, not all
matching terms are executed, and the default is not discard.
Q4 ANALYZE JUNOS OS ARCHITECTURE AND PACKET FLOW TO DIAGNOSE COMPLEX
NETWORK ISSUES
You are tasked with configuring a class-of-service (CoS) policy to ensure that
voice traffic (EF) experiences lower latency and jitter than bulk data (BE). Which
CoS components must be configured to achieve this, and what is the correct
sequence of operations?
A. Classifiers, schedulers, and rewrite rules; applied in that order. CORRECT
B. Schedulers, classifiers, and drop profiles; applied in that order.
C. Classifiers, drop profiles, and schedulers; applied in any order.
D. Drop profiles, schedulers, and classifiers; applied in that order.
RATIONALE: CoS architecture requires classifiers to assign packets to forwarding classes,
schedulers to prioritize transmission, and rewrite rules to set the output packet headers. The
order is classifiers, then schedulers, then rewrite rules. Drop profiles are part of schedulers, not a
separate top-level component. The other options have incorrect order or components.
Page 3
, Q5 ANALYZE JUNOS OS ARCHITECTURE AND PACKET FLOW TO DIAGNOSE COMPLEX
NETWORK ISSUES
In Junos, which routing protocol uses the concept of 'active route' and 'backup
route' to populate the routing table, and how does Junos handle multiple routes to
the same destination from different protocols?
A. OSPF; uses administrative distance to select the active route.
B. BGP; uses local preference and AS path length to select the active route.
C. All protocols; Junos uses route preference (administrative distance) to select the active route
and keeps all others as backups. CORRECT
D. IS-IS; uses metric to select the active route and discards others.
RATIONALE: Junos maintains a single active route per destination in the forwarding table,
chosen by the lowest route preference (administrative distance) among all protocols. Other
routes are kept as backup routes in the routing table but not installed in the forwarding table
unless the active route fails. This applies to all protocols, not just OSPF or BGP. Route
preference is a Junos-specific term for administrative distance.
Q6 ANALYZE JUNOS OS ARCHITECTURE AND PACKET FLOW TO DIAGNOSE COMPLEX
NETWORK ISSUES
An engineer needs to automate configuration of multiple Junos devices. They
decide to use Junos PyEZ to push configuration changes. Which of the following
best describes the correct usage of PyEZ to load and commit a configuration from
a file?
A. Use the 'load' method with 'path' argument to load the file, then call 'commit' on the device.
B. Use the 'load_config' method with 'path' and 'merge' parameters, then call 'commit' on the
device. CORRECT
C. Use the 'open' method to read the file, then use 'configure' to apply changes, then 'commit'.
D. Use the 'send' method to execute CLI commands to load and commit the configuration.
RATIONALE: PyEZ provides the 'load_config' method on a Device instance to load configuration
from a file or string, with options like 'merge' or 'replace'. After loading, you call 'commit' to apply.
The 'load' method is not a PyEZ method; it's a CLI command. 'open' is used to connect, not to
load config. 'send' is for executing CLI commands, not for loading config files.
Page 4
