JNCIP-ENT Practice Test 13 — 15 Questions

Question 1

Which command displays the configured scheduler maps and their association with forwarding classes on a Junos device?

Accepted Answer

show class-of-service scheduler-map. The show class-of-service scheduler-map command displays details of scheduler maps and queue associations.

Answer

show class-of-service queue

Answer

show class-of-service forwarding-class

Answer

show configuration class-of-service schedulers

Question 2

Which TWO security features can be configured on Juniper EX switches to prevent DHCP spoofing and ARP poisoning attacks on Layer 2 access ports? (Choose two)

Accepted Answer

DHCP snooping. DHCP snooping and Dynamic ARP Inspection (DAI) prevent DHCP spoofing and ARP poisoning respectively.

Answer

Storm control

Answer

BPDU guard

Answer

MACsec encryption

Question 3

An engineer is troubleshooting a newly configured EVPN-VXLAN multi-homed setup where the Designated Forwarder (DF) is constantly toggling between two PE routers. What is the most likely cause of this DF churn?

Accepted Answer

Mismatched Ethernet Segment Identifiers (ESIs) or unstable BGP connectivity between PEs.. DF churn typically occurs when BGP sessions or reachability between the PE routers flapping, or when the timers (such as wait-for-timer) are misconfigured, causing conflicting DF election states.

Answer

Incorrect MAC mobility sequence numbers.

Answer

Exceeding the maximum MAC address table limit.

Answer

Using VXLAN instead of MPLS data plane encapsulation.

Question 4

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 5

Which THREE parameters are typically included or evaluated when configuring and verifying BGP EVPN peer sessions on Junos OS devices? (Choose three)

Accepted Answer

Route targets (import and export) to control the exchange of EVPN routes between routing instances.. BGP EVPN peering requires the BGP neighbor IP/address family configuration, Route Targets for import/export control, and Route Distinguishers for uniqueness within the routing instance.

Answer

RSVP bandwidth reservation for the BGP TCP session.

Answer

Spanning tree priority configuration for the BGP peering interface.

Question 6

An engineer is configuring PIM sparse-mode in an enterprise network. Which TWO characteristics are true regarding PIM sparse-mode operation? (Choose two)

Accepted Answer

It uses explicit join messages (*,G or S,G) sent towards the RP or source.. Option C is correct because PIM-SM is an explicit-join protocol: receivers' DRs send (*,G) joins toward the Rendezvous Point and, after the shortest-path tree switchover, (S,G) joins toward the source, building distribution trees only where membership exists. Option E is correct because PIM-SM uses a shared tree rooted at the RP to connect sources and receivers initially, with the RP forwarding traffic until routers can join the source-specific shortest-path tree. Option A is wrong because PIM-SM does not mandate IGMPv3 on every interface; IGMPv2 or IGMPv3 may be used, and IGMP is only relevant on receiver-facing segments. Option B is wrong because flooding-until-pruned behavior describes PIM dense mode, not sparse mode. Option D is wrong because PIM-SM relies on the unicast routing table (or MRIB) for RPF checks to prevent loops and select the correct upstream neighbor.

Answer

It requires every interface to run IGMPv3 exclusively.

Answer

It floods multicast traffic across all router interfaces by default until pruned.

Answer

It does not require any unicast routing protocol for RPF checks.

Question 7

An engineer needs to view the MSDP Source-Active (SA) cache on a Junos router to verify which sources are currently active across different PIM domains. Which operational command should be executed?

Accepted Answer

show msdp source-active. The 'show msdp source-active' command displays the contents of the MSDP SA cache.

Answer

show multicast source-cache

Answer

show bgp msdp active

Answer

show pim source-active

Question 8

Which Junos command displays the link-state database for OSPFv2, showing router LSAs and network LSAs?

Accepted Answer

show ospf database. The command 'show ospf database' displays the OSPF link-state database on a Junos device.

Answer

show route ospf database

Answer

show link-state ospf database

Answer

show protocols ospf database

Question 9

A Junos router receives a BGP route containing multiple extended and large communities. The administrator writes a routing policy to filter routes based on large communities. Which format is used to define a large community in Junos policy-options?

Accepted Answer

large-community:global_administrator:local_data1:local_data2. Large communities in Junos policy-options are defined using the format large-community:global_administrator:local_data1:local_data2.

Answer

as-number:identifier

Answer

target:as-number:identifier

Answer

ipv4-address:identifier

Question 10

An administrator is deploying EVPN multi-homing with all-active mode on an MX Series router. Which configuration element uniquely identifies the provider edge (PE) router's attachment circuit to an Ethernet segment?

Accepted Answer

Ethernet Segment Identifier (ESI). The Ethernet Segment Identifier (ESI) is a 10-octet unique identifier configured under the interface or access link to identify an Ethernet segment for multi-homing.

Answer

Route Distinguisher (RD)

Answer

Ethernet Tag ID

Answer

ESI Label Extended Community

Question 11

Which BGP community is a well-known transitive community used to prevent a route from being advertised outside of a local autonomous system?

Accepted Answer

no-export. The NO_EXPORT well-known community instructs a BGP peer not to advertise the affected route to any external BGP peers.

Answer

no-peer

Answer

local-as

Answer

no-advertise

Question 12

You need to modify the priority of a Junos OSPF interface to ensure it becomes the designated router (DR). Which command accomplishes this?

Accepted Answer

set protocols ospf area 0.0.0.0 interface xe-0/0/0.0 priority 200. OSPF interface priority is configured under the interface level within protocols ospf using the 'priority' command.

Answer

set interfaces xe-0/0/0.0 ospf-priority 200

Answer

set protocols ospf priority 200 interface xe-0/0/0.0

Answer

set protocols ospf area 0.0.0.0 interface xe-0/0/0.0 dr-priority 200

Question 13

Which THREE features or protocols are used in Juniper enterprise switching environments to prevent Layer 2 bridging loops while avoiding traditional Spanning Tree blocking ports? (Choose three)

Accepted Answer

Virtual Chassis technology. MC-LAG, Virtual Chassis, and EVPN-VXLAN eliminate loops via active-active multi-pathing or distributed control planes without traditional STP blocking links.

Answer

Rapid PVST+ with bridge priority overrides

Answer

MSTP with MSTI region mapping

Question 14

You want to tag specific BGP routes with a community value using a Junos policy framework. Which configuration snippet correctly defines a community named 'CUSTOM-COMM' with value 65000:100?

Accepted Answer

set policy-options community CUSTOM-COMM members 65000:100. In Junos, BGP communities are defined under 'policy-options community' with a name and the community value specified in format AS:number or target:AS:number.

Answer

set routing-options community-list CUSTOM-COMM value 65000:100

Answer

set protocols bgp group external community CUSTOM-COMM 65000:100

Answer

set policy-options policy-statement CUSTOM-COMM community 65000:100

Question 15

You are configuring MAC limiting on an EX Series switch interface to restrict the maximum number of learned MAC addresses to 10. What happens when the 11th unique MAC address attempts to communicate through the interface?

Accepted Answer

The switch drops packets from the new MAC address and optionally logs or generates an SNMP trap.. By default, MAC limit drop or log actions occur. The standard configurable action when a limit is exceeded includes dropping the packet or shutting down the port.

Answer

The switch immediately reboots the line card to protect the control plane.

Answer

The switch forwards the frame and clears the oldest learned MAC entry from the forwarding table.

Answer

The switch dynamically converts the port into a routed Layer 3 interface.