JNCIP-ENT Practice Test 1 — 25 Questions

Question 1

An enterprise network uses BGP communities to tag routes at regional branch offices. Headquarters needs to strip these specific communities from routes before advertising them to external transit providers. Which Junos routing policy action accomplishes this?

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

Accepted Answer

community delete target_community. Using the 'community delete' action within a routing policy removes specified communities from routes matching the policy.

Answer

community set target_community

Answer

as-path-remove target_community

Answer

metric set 0

Question 2

Which THREE methods can be used on Junos devices to influence inbound BGP traffic selection from external ASNs? (Choose three)

Accepted Answer

AS path prepending outbound to external peers.. Inbound traffic from external peers can be influenced by AS path prepending, modifying MED, or utilizing specific BGP communities accepted by transit providers.

Answer

Adjusting the local preference attribute on incoming EBGP updates.

Answer

Changing the local router's weight attribute for incoming EBGP routes.

Question 3

Which TWO actions can be performed using Junos BGP routing policies? (Choose two)

Accepted Answer

Modifying the local preference attribute of incoming IBGP routes.. Junos routing policies can filter routes and modify path attributes such as local preference or MED.

Answer

Dynamically altering the BGP session TCP handshake port numbers.

Answer

Adjusting the BGP keepalive timer values dynamically via policy match actions.

Answer

Manually assigning physical interface MTU sizes for BGP sessions.

Question 4

Which TWO types of OSPF areas allow the generation of Type-7 LSAs? (Choose two)

Accepted Answer

Not-So-Stubby Area (NSSA). Type-7 LSAs are exclusively generated within Not-So-Stubby Areas (NSSA) and NSSA totally stubby areas by ASBRs connecting external routes.

Answer

Standard OSPF Non-backbone Area

Answer

Standard OSPF Backbone Area (Area 0)

Answer

OSPF Stub Area

Question 5

Which THREE parameters must match between two OSPF routers on a shared broadcast segment for an adjacency to successfully form? (Choose three)

Accepted Answer

Router ID. OSPF hello/dead timers, area ID, and authentication parameters must match between neighbors to establish an adjacency.

Answer

Interface MTU size

Answer

Interface primary IP address subnet

Question 6

An administrator configures a scheduler map with a transmit-rate of percent 20 for a queue, but the total sum of transmit-rates in the map equals 110%. How does Junos handle this configuration?

Accepted Answer

The commit fails because the sum of percentage transmit-rates exceeds 100%. Junos requires the sum of transmit-rates defined as percentages in a scheduler map to not exceed 100%. If it exceeds 100%, the configuration commit will fail.

Answer

Traffic exceeding 100% is dropped by the Routing Engine

Answer

Junos normalizes the percentages proportionally during commit time

Answer

The excess 10% is automatically assigned to the best-effort queue

Question 7

Which TWO conditions must be met when configuring strict priority queuing for a forwarding class in Junos? (Choose two)

Accepted Answer

A shaping rate should be applied to the priority queue to prevent starvation of other queues. Strict priority queues require a priority setting (high) and typically a shaping rate or limit to prevent starvation of other queues.

Answer

Behavior aggregate classifiers must be disabled on all egress interfaces

Answer

Buffer sizes must be set to zero for all priority queues

Answer

The scheduler must have a transmit-rate percentage of exactly 100%

Question 8

Which command should an engineer use on a Junos device to verify whether a BGP next hop is successfully resolved via the routing table?

Accepted Answer

show route protocol bgp next-hop. The 'show route protocol bgp next-hop' command displays all BGP next hops and indicates whether they are resolved in the routing table.

Answer

show bgp neighbor detail

Answer

show route forwarding-table destination

Answer

show bgp summary

Question 9

Which THREE methods are valid for marking packet headers using CoS rewrite rules in Junos? (Choose three)

Accepted Answer

exp. Rewrite rules can modify DSCP, EXP, and IEEE 802.1p fields.

Answer

vlan-id

Answer

mpls-ttl

Question 10

During BGP route resolution on Junos, an indirect next hop is encountered. What mechanism does Junos use to resolve this indirect next hop to a direct forwarding next hop?

Accepted Answer

Recursive lookups through the routing table using the active IGP or static route entries.. Junos relies on the underlying IGP (OSPF or IS-IS) or static routes to resolve indirect BGP next hops to direct interface and gateway forwarding entries.

Answer

BGP Link-State (BGP-LS) topology databases.

Answer

Multiprotocol Label Switching (MPLS) label imposition without routing table participation.

Answer

Address Resolution Protocol (ARP) directly against the BGP peer IP address.

Question 11

An engineer needs to ensure that a Junos router balances BGP traffic across multiple paths with unequal IGP costs. Which feature must be configured to achieve this?

Accepted Answer

BGP multipath with the 'as-path-relax' or equivalent multipath options enabled.. By default, BGP multipath requires equal cost. To allow paths with different costs, 'as-path-multipath' or variance-based multipath configurations are required depending on specific Junos platform support, but generally standard multipath requires equal IGP cost unless specific multipath relaxation options are set.

Answer

Setting the MED attribute to zero on all incoming EBGP updates.

Answer

Configuring static routes with identical preferences for every BGP prefix.

Answer

Enabling BGP Route Reflection on the local routing engine.

Question 12

Which THREE parameters are part of the standard Junos BGP route selection algorithm prior to evaluating the router ID? (Choose three)

Accepted Answer

Weight (local to the router). Before router ID, Junos evaluates Weight, Local Preference, AS path length, Origin, MED, and IBGP vs EBGP preference.

Answer

Cluster List length

Answer

Originator ID value

Question 13

Which Junos configuration hierarchy is used to define a BGP peer group to simplify neighbor configurations?

Accepted Answer

protocols bgp group <group-name>. BGP peer groups and neighbor settings are configured under the 'protocols bgp group' hierarchy in Junos.

Answer

routing-options autonomous-system

Answer

interfaces <interface-name> unit 0 family inet bgp

Answer

policy-options community

Question 14

You need to configure a classifier that inspects the Multiprotocol Label Switching (MPLS) experimental (EXP) bits. Which classifier type must you specify?

Accepted Answer

exp. The MPLS EXP bits are classified using the exp classifier type in Junos CoS configurations.

Answer

fec

Answer

ieee-802.1

Answer

dscp

Question 15

You are troubleshooting a scenario where multi-field classifiers and behavior aggregate classifiers are both configured on the same ingress interface. In what order does Junos process classification?

Accepted Answer

Behavior aggregate classification is evaluated first, and multi-field classification can override the result. Junos processes Behavior Aggregate (BA) classification first, followed by Multi-Field (MF) classification which can override the BA result.

Answer

Junos rejects configurations where both BA and MF classifiers are applied to the same interface

Answer

Both classifiers are executed simultaneously in hardware without precedence

Answer

Multi-field classification is evaluated first, followed by behavior aggregate classification

Question 16

In Junos CoS architecture, what role does a forwarding class play?

Accepted Answer

It represents an internal queue abstraction used to group and process packets. Forwarding classes act as internal labels used by the router to group traffic into specific queues for scheduling and drop treatment.

Answer

It specifies the egress interface physical speed

Answer

It provides static IP routing table entries

Answer

It defines the physical queue index directly on the ASIC

Question 17

Which command allows an administrator to view the active BGP routes along with their associated communities on a Junos device?

Accepted Answer

show route protocol bgp extensive. The 'show route protocol bgp' command with the 'extensive' modifier displays detailed path attributes including BGP communities.

Answer

show bgp group summary

Answer

show bgp neighbor extensive

Answer

show route forwarding-table protocol bgp

Question 18

Which command allows you to view the configured drop-profile statistics and monitor packet drop counts on an MX Series router?

Accepted Answer

show class-of-service drop-profile. The show class-of-service drop-profile command displays drop-profile utilization and drop statistics.

Answer

show firewall log

Answer

show interfaces drop-rate

Answer

show system drop-stats

Question 19

Which TWO statements describe the characteristics of Random Early Detection (RED) and drop profiles in Junos? (Choose two)

Accepted Answer

Drop profile curves plot drop probability against queue buffer fill level. Drop profiles define drop probability against fill level, helping prevent TCP global synchronization.

Answer

Drop profiles are configured under the forwarding-classes hierarchy

Answer

Drop profiles drop 100% of packets immediately once the queue fill level reaches the start point

Answer

Drop profiles operate exclusively on Layer 2 control frames

Question 20

When configuring a BGP route reflector cluster in Junos, which THREE guidelines or operational behaviors should an engineer keep in mind? (Choose THREE)

Accepted Answer

A route reflector must never reflect routes received from a non-client peer back to other non-client peers.. Route reflectors reflect routes between clients and non-clients. Loop prevention uses Originator ID and Cluster List. Redundant RRs in the same cluster must share the same cluster ID to prevent routing loops and oscillation.

Answer

Clients of a route reflector must be configured in a full iBGP mesh with each other.

Answer

Route reflectors automatically modify the AS_PATH attribute of all reflected routes.