JNCIP-ENT Practice Test 3 — 25 Questions

Question 1

Which TWO statements are correct regarding hierarchical scheduling (H-QoS) on Juniper MX Series routers? (Choose two)

Accepted Answer

Subscriber management frameworks often utilize hierarchical scheduler maps. Hierarchical schedulers allow multi-level bandwidth allocation and tenant sub-rate shaping.

Answer

H-QoS eliminates the need for physical interface drop profiles

Answer

H-QoS is configured exclusively under the system routing-options hierarchy

Answer

H-QoS requires disabling all hardware-based forwarding ASICs

Question 2

You are configuring VSTP (VLAN Spanning Tree Protocol) on Juniper EX switches to interoperate with legacy third-party switches running PVST+. Which operational command allows you to verify the VSTP bridge identifier and root bridge status per VLAN?

Accepted Answer

show vstp vlan. The command 'show vstp vlan' displays the VSTP state, root bridge, and port roles for each VLAN.

Answer

show ethernet-switching vstp

Answer

show spanning-tree vlan detail

Answer

show bridge vstp-status

Question 3

An administrator needs to filter Type-3 LSAs entering an OSPF stub area on a Junos routing device. Which statement under the area hierarchy is required?

Accepted Answer

set protocols ospf area 0.0.0.2 area-range 192.168.1.0/24 restrict. In Junos OS, you can filter inbound Type-3 LSAs into a stub or NSSA area using the 'area-range' command with the 'restrict' or 'hidden' parameter, or using an import policy at the area level, but specifically for summarization and blocking, the area-range statement with 'restrict' prevents the LSA from being advertised.

Answer

set protocols ospf area 0.0.0.2 type-3-lsa-block

Answer

set protocols ospf area 0.0.0.2 stub lsa-filter block-type-3

Answer

set protocols ospf area 0.0.0.2 filter type-3-lsa

Question 4

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 5

You want to tune OSPF convergence by reducing the hello and dead intervals on a point-to-point interface. Which configuration is valid?

Accepted Answer

set protocols ospf area 0.0.0.0 interface xe-0/0/0.1 hello-interval 1. OSPF interface timers such as hello-interval and dead-interval are configured directly under the interface hierarchy within protocols ospf.

Answer

set protocols ospf area 0.0.0.0 timers hello-interval 1

Answer

set interfaces xe-0/0/0.1 ospf hello-interval 1

Answer

set protocols ospf hello-interval 1 dead-interval 4

Question 6

When configuring EVPN multi-homing in all-active mode, which THREE key components or concepts must be properly established across the PE routers? (Choose three)

Accepted Answer

A Designated Forwarder (DF) election mechanism using Type-4 routes to determine who forwards BUM traffic.. EVPN all-active multi-homing requires a consistent Ethernet Segment Identifier (ESI) across participating PEs, an active Designated Forwarder election (governed by Type-4 routes), and split-horizon filtering to prevent traffic loops.

Answer

Enabling Spanning Tree Protocol root bridge on all leaf nodes.

Answer

Configuring OSPF as the underlay routing protocol for EVPN signaling.

Question 7

Which TWO actions can be performed by an OSPF routing policy export filter when redistributing routes into OSPF? (Choose two)

Accepted Answer

Modify the OSPF route metric using the metric action.. Routing policies when exporting into OSPF can set metric types (Type 1 or Type 2) and modify route metrics. They cannot directly change area ID during redistribution without area design changes.

Answer

Change the OSPF hello timer interval via routing policy.

Answer

Alter the OSPF router ID of neighboring routers.

Answer

Change the OSPF area ID of external routes dynamically.

Question 8

An engineer configures an EVPN instance with multiple bridge domains. Each bridge domain requires a unique VNI. Where are the VNI values mapped to their respective bridge domains in Junos OS?

Accepted Answer

Under routing-instances bridge-domains vni . In Junos OS, VNI values are mapped under the 'bridge-domains' hierarchy using the 'vni ' statement.

Answer

Under protocols bgp neighbor configuration

Answer

Under interfaces loopback unit 0 vni

Answer

Under policy-options community definition

Question 9

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.

Question 10

An enterprise network engineer is designing a redundant Layer 2 topology with MSTP across Juniper EX switches. Two switches have identical bridge priorities and MAC addresses that result in a tie for regional root. How does MSTP deterministically break the tie to select the regional root bridge?

Accepted Answer

The switch with the numerically lowest MAC address is selected as the root bridge.. Spanning tree tie-breaking checks the bridge priority first, and if tied, compares the lowest MAC address of the switches.

Answer

The switch with the highest interface count operational status wins.

Answer

The switch with the higher serial number stored in EEPROM is chosen.

Answer

MSTP triggers a randomized tie-breaker algorithm using the system uptime.

Question 11

You are configuring MACsec (Media Access Control Security) on an EX Series switch interface to secure Layer 2 links between two enterprise buildings. Which requirement is mandatory for MACsec to establish a secure session successfully between the two switches?

Accepted Answer

Both switches must have identical pre-shared keys (connectivity association keys) and matching cipher suites configured.. MACsec requires pre-shared keys (PSK) or MKA (MACsec Key Agreement) with matching connectivity association keys (CAK) and cipher suites.

Answer

Both switches must run RSVP-TE to reserve bandwidth for encrypted frames prior to session establishment.

Answer

Both switches must disable Spanning Tree Protocol on the MACsec-secured interface.

Answer

Both switches must be configured as part of the same VSTP region.

Question 12

Which THREE mechanisms are provided by Juniper switches running MSTP to protect against bridging loops caused by unidirectional link failures or misbehaving switches? (Choose three)

Accepted Answer

Root guard. Loop guard, root guard, and bpdu guard are standard STP/MSTP protection features available on Juniper switches.

Answer

Storm control broadcast filtering

Answer

MACsec cryptographic validation

Question 13

An OSPF area in your network contains multiple ABRs. You need to suppress the generation of Type-4 summary LSAs into a totally stubby area. How does Junos handle this natively?

Accepted Answer

Totally stubby areas automatically block Type-4 LSAs by design without additional configuration.. Totally stubby areas automatically block Type-3, Type-4, and Type-5 LSAs. No separate command is needed to suppress Type-4 LSAs once an area is defined as a totally stubby area.

Answer

You must apply an export policy on the ABR blocking Type-4 LSAs.

Answer

You must use set protocols ospf suppress-fa to remove Type-4 LSAs.

Answer

You must configure set protocols ospf area <area> stub no-summary-asbr.

Question 14

You are troubleshooting MAC address learning on an EX Series switch and want to display dynamic MAC entries learned specifically on interface ge-0/0/5. Which operational command should you use?

Accepted Answer

show bridge mac-table interface ge-0/0/5. The command 'show bridge mac-table interface ge-0/0/5' displays MAC addresses learned on that interface.

Answer

show mac-address-table interface ge-0/0/5

Answer

show ethernet-switching table port ge-0/0/5

Answer

show l2-learning interface ge-0/0/5 macs

Question 15

Which TWO parameters are part of the standard MSTP configuration digest computed across switches in an MST region? (Choose two)

Accepted Answer

MST configuration name. The MST configuration digest includes region name, revision number, and the VLAN-to-instance allocation table.

Answer

Bridge priority value

Answer

Interface MAC addresses

Answer

Hello time and max age timers

Question 16

Which TWO of the following statements regarding EVPN Route Type 1 (Ethernet Auto-Discovery Route) are correct? (Choose two)

Accepted Answer

Type 1 routes are advertised either per-EVI or per-Ethernet Segment (ES).. Route Type 1 comes in two variants: per-EVI and per-ES. Per-EVI routes provide aliasing for load-balancing across multi-homed PEs, and per-ES routes facilitate fast convergence during node failures.

Answer

Type 1 routes are only used in single-homed network topologies.

Answer

Type 1 routes are exclusively used for mapping IP prefixes to IP-VRFs.

Answer

Type 1 routes replace Type 3 routes for handling BUM traffic replication.

Question 17

When configuring advanced Q-in-Q tunneling on Juniper MX Series routers, which THREE encapsulation or tagging parameters must be correctly aligned between the customer edge and provider edge interfaces? (Choose three)

Accepted Answer

VLAN action rules (pop, push, or swap). Q-in-Q alignment requires matching flexible-vlan-tagging, TPID values (EtherType), and VLAN tag preservation/manipulation rules.

Answer

MSTP region name configuration

Answer

IGMP snooping version compatibility

Question 18

Which TWO statements describe the behavior of VSTP (VLAN Spanning Tree Protocol) on Juniper EX Series switches? (Choose two)

Accepted Answer

VSTP can interoperate with Cisco's PVST+ protocol.. VSTP runs an independent spanning tree instance per VLAN and interoperates with PVST+.

Answer

VSTP is incompatible with RSTP fallback modes.

Answer

VSTP automatically disables all trunk ports if BPDU guard is triggered globally.

Answer

VSTP requires all VLANs to be mapped into a single master MSTI region.

Question 19

When designing a high-scale enterprise campus network using Juniper EX Series switches, which THREE best practices should be followed for Spanning Tree Protocol design? (Choose three)

Accepted Answer

Enable BPDU guard and loop guard on all edge access ports.. Best practices include placing root bridges at the core/distribution layer, using edge protection features, and maintaining consistent region parameters.

Answer

Use default bridge priority values on all core switches to allow automated root election.

Answer

Disable Spanning Tree entirely on all access ports to ensure faster convergence.

Question 20

Which EVPN route type is responsible for advertising MAC addresses combined with IP addresses (MAC/IP Advertisement Route)?

Accepted Answer

Route Type 2. Route Type 2 is the MAC/IP Advertisement Route, which carries a MAC address and optionally an IP address, facilitating both L2 bridging and L3 host routing.

Answer

Route Type 3

Answer

Route Type 4

Answer

Route Type 1