JNCIP-ENT Practice Test 3 — 10 Questions

Question 1

Which OSPFv3 LSA type is responsible for carrying IPv6 prefix information within the same area, replacing the role of Router and Network LSAs carrying IP addresses in OSPFv2?

Accepted Answer

Type 9 (Intra-Area-Prefix LSA). OSPFv3 separates topology information from IP prefix information. Type-9 (Intra-Area-Prefix-LSA) carries IPv6 prefixes associated with routers or transit networks within the area.

Answer

Type 1 (Router LSA)

Answer

Type 5 (AS-External LSA)

Answer

Type 3 (Inter-Area-Prefix LSA)

Question 2

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 3

Which TWO of the following statements correctly describe the operation and benefits of EVPN MAC mobility? (Choose two)

Accepted Answer

It uses sequence numbers attached to Type-2 routes to track host movement between different PEs.. EVPN MAC mobility uses sequence numbers in the MAC Mobility Extended Community to detect when a host moves between PEs, preventing blackholing and updating forwarding tables correctly.

Answer

It forces BGP session resets whenever a MAC address moves between subnets.

Answer

It is exclusively used for Route Type 4 Designated Forwarder election.

Answer

It requires Spanning Tree Protocol to be enabled to detect host migration.

Question 4

An enterprise design uses PIM sparse-mode with a BSR. An engineer notices that the router has successfully elected a BSR, but no Candidate-RP messages are being processed. Which operational command should the engineer use to verify the BSR candidate information and elected BSR address on the router?

Accepted Answer

show pim bsr statistics. The 'show pim bsr local' or 'show pim bsr' commands display information regarding the BSR state, elected BSR, and received bootstrap messages.

Answer

show igmp bsr

Answer

show msdp bsr-state

Answer

show multicast bsr

Question 5

Which IPv4 address is assigned as the all-systems multicast group address, used by routers to query all hosts on a local subnet?

Accepted Answer

224.0.0.1. 224.0.0.1 is the all-hosts (all-systems) multicast group address.

Answer

224.0.0.22

Answer

224.0.0.13

Answer

224.0.0.2

Question 6

An enterprise network uses a BGP route reflector (RR) architecture where client routers reflect routes to each other. A non-client router sends a route with an Originator ID and Cluster List to the RR. How does the route reflector handle these attributes when reflecting the route to other clients?

Accepted Answer

It leaves the Originator ID intact and appends its own cluster ID to the Cluster List.. A route reflector leaves the Originator ID untouched and prepends its own Cluster ID to the existing Cluster List to prevent routing loops.

Answer

It removes the Originator ID and replaces the Cluster List with its own cluster ID.

Answer

It increments the Originator ID value by one and clears the Cluster List.

Answer

It clears both the Originator ID and Cluster List to reset loop detection for the local cluster.

Question 7

An engineer is configuring a QinQ tunnel where the service provider bridge needs to transparently carry customer control traffic (like STP BPDUs) through the core without processing them. What feature must be enabled on the provider edge access ports?

Accepted Answer

Layer 2 Protocol Tunneling (L2PT). Layer 2 Protocol Tunneling (L2PT) encapsulates customer BPDUs into specific multicast destination MAC addresses at the ingress edge, tunnels them across the provider core, and un-encapsulates them at the egress edge.

Answer

VLAN Translation

Answer

Rapid Spanning Tree Protocol (RSTP)

Answer

BPDU Protection (bpdu-block)

Question 8

What is the primary function of a behavior aggregate (BA) classifier in Junos CoS?

Accepted Answer

It classifies packets based exclusively on header CoS bits such as DSCP or EXP. A Behavior Aggregate (BA) classifier classifies packets based solely on the CoS bits in the packet header (such as DSCP, EXP, or IEEE 802.1p).

Answer

It drops packets exceeding a predefined bandwidth rate

Answer

It rewrites VLAN tags on egress interfaces

Answer

It classifies packets based on Layer 4 port numbers and source IP addresses

Question 9

You are designing an enterprise network running Multiple Spanning Tree Protocol (MSTP) across multiple data center switches. To ensure that switches belong to the same MST region, which three parameters must match identically across all switches in that region?

Accepted Answer

Region name, revision number, and VLAN-to-instance mapping. According to IEEE 802.1s, switches belong to the same MST region if and only if they share the exact same configuration name, revision number, and VLAN-to-instance mapping table.

Answer

VLAN-to-instance mapping, bridge priority, and MAC address

Answer

Bridge priority, region name, and maximum age timer

Answer

Root bridge ID, region name, and revision number

Question 10

Which IPv4 multicast address range is designated for Source-Specific Multicast (SSM) operations according to IANA standards?

Accepted Answer

232.0.0.0/8. The range 232.0.0.0/8 is reserved for Source-Specific Multicast (SSM) by IANA.

Answer

224.0.1.0/24

Answer

224.0.0.0/24

Answer

239.0.0.0/8