JNCIP-ENT Practice Test 2 — 25 Questions

Question 1

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?

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

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.

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

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

Question 2

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

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Rapid Spanning Tree Protocol (RSTP)

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BPDU Protection (bpdu-block)

Question 3

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

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It rewrites VLAN tags on egress interfaces

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

Question 4

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

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Bridge priority, region name, and maximum age timer

Answer

Root bridge ID, region name, and revision number

Question 5

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

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224.0.0.0/24

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239.0.0.0/8

Question 6

A network administrator wants to advertise an aggregate BGP route while suppressing the more specific component routes from being sent to external peers. Which Junos routing-options configuration achieves this?

Accepted Answer

Configure the aggregate route with the 'summary-only' parameter under routing-options bgp.. Using the 'aggregate' statement with the 'summary-only' option generates the aggregate prefix and suppresses all component specific routes.

Answer

Enable BGP dampening on the aggregate route and disable it on the component routes.

Answer

Apply a routing policy that sets the NO_EXPORT community on all component routes.

Answer

Configure an aggregate route with the 'discard' policy and apply an export policy that drops component routes.

Question 7

You want to configure voice VLAN functionality on a Juniper EX switch so that IP phones automatically place voice traffic into VLAN 50 while passing PC data through unchanged. Which feature should you configure?

Accepted Answer

LLDP-MED with voice VLAN assignment. Voice VLAN feature on EX switches automatically assigns voice traffic from known MAC OUIs to the designated voice VLAN.

Answer

MAC-based RADIUS dynamic VLAN assignment

Answer

Layer 2 protocol tunneling (L2PT)

Answer

IEEE 802.1X supplicant authentication

Question 8

Which protocol version introduces explicit source inclusion and exclusion lists (TO_EX, TO_IN, IS_IN, IS_EX) in membership reports?

Accepted Answer

IGMPv3. IGMPv2 supports basic group membership, whereas IGMPv3 introduces source-filtering capabilities allowing hosts to specify include or exclude source lists.

Answer

IGMPv2

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IGMPv4

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IGMPv1

Question 9

You are configuring a BGP Route Reflector (RR) in a Junos environment. To prevent routing loops within the iBGP cluster, what mechanism does the route reflector use to track the path of reflected routes?

Accepted Answer

Cluster List and Originator ID attributes. Route reflectors use the 'Originator ID' (a 4-byte attribute containing the router ID of the route originator) and the 'Cluster List' (a sequence of cluster IDs through which the route has passed) to prevent routing loops.

Answer

MED comparison and router ID tie-breakers

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AS Path prepending and local preference manipulation

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TTL security decrement and loose reverse path forwarding

Question 10

Which command verifies the OSPF neighbor states and adjacency progress on a Junos device?

Accepted Answer

show ospf neighbor. The 'show ospf neighbor' command displays OSPF neighbor states, interface, and dead timer details.

Answer

show route table ospf.0 neighbor

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show protocols ospf neighbors

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show ospf adjacency

Question 11

When configuring a BGP confederation, how are external peers outside the confederation affected by the internal sub-AS structure?

Accepted Answer

They see only the top-level confederation AS number in the AS path attribute.. External peers outside the confederation see only the top-level confederation AS number, as internal member AS numbers are stripped when exiting the confederation boundary.

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They require explicit configuration of every member AS in their own EBGP import filters.

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They see all member AS numbers prepended individually in the AS path.

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They reject all updates originating from a confederation due to AS path validation failures.

Question 12

An administrator configures BGP dampening on a Junos router to mitigate the impact of flapping routes. When a route exceeds the reuse threshold after being suppressed, what happens to its penalty value?

Accepted Answer

The penalty value continues to decay exponentially until it drops to zero.. When a dampened route's penalty decays below the reuse threshold, the route becomes eligible again, and its penalty continues to decay exponentially toward zero.

Answer

The penalty value is locked at the reuse threshold value indefinitely.

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The penalty value is doubled to discourage further flapping.

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The penalty value is instantly reset to zero.

Question 13

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 14

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 15

Which EVPN route type is responsible for establishing ingress replication lists for Broadcast, Unknown Unicast, and Multicast (BUM) traffic?

Accepted Answer

Route Type 3. Route Type 3 (Inclusive Multicast Ethernet Tag Route) is used to build the peer list for BUM traffic distribution using ingress replication (head-end replication).

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Route Type 5

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Route Type 4

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Route Type 1

Question 16

How do you examine the specific OSPF routing table entries learned via OSPF on a Junos device?

Accepted Answer

show route protocol ospf. The 'show route protocol ospf' command displays routes learned specifically through the OSPF routing protocol.

Answer

show protocols ospf route-table

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show ospf routes

Answer

show ip route ospf

Question 17

Which THREE configuration tasks are required when implementing OSPFv3 on Junos devices? (Choose three)

Accepted Answer

Enabling OSPFv3 under the protocols ospf3 hierarchy. Configuring OSPFv3 requires specifying protocols ospf3, configuring areas, and enabling OSPFv3 on specific interfaces (IPv6 enabled).

Answer

Configuring BGP autonomous system numbers for OSPFv3 operation

Answer

Enabling IPv4 address families inside protocols ospf3

Question 18

Which THREE statements describe the behavior of LLDP-MED capability on Junos EX Series switches? (Choose three.)

Accepted Answer

It automates network policy configuration for voice, video, and guest VLANs.. LLDP-MED enables advanced capabilities like device location, inventory management, and network policies for endpoints.

Answer

It replaces the need for Ethernet switching entirely by converting access ports into routed links.

Answer

It requires OSPFv3 to be running on all connected IP phones.

Question 19

An administrator notices that broadcast, unknown unicast, and multicast (BUM) traffic sent from a local host is looping back to the originating multi-homed PE when using an all-active Ethernet segment. Which mechanism prevents this loop in EVPN?

Accepted Answer

EVPN Split Horizon filtering using ESI labels. EVPN uses Split Horizon filtering via the ESI Label Extended Community or local split-horizon checks to ensure that BUM traffic received from a remote PE on a shared Ethernet segment is not sent back out to the same segment.

Answer

BGP Best Path Selection algorithm

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Designated Forwarder (DF) election

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Spanning Tree Protocol (STP) root guard

Question 20

Which TWO options are valid authentication methods that can be specified in the 'authentication-order' statement on an EX Series switch interface? (Choose two)

Accepted Answer

mac-radius. On Juniper EX Series switches, the 'authentication-order' statement under an interface (or globally) accepts authentication methods such as 'dot1x', 'mac-radius', and 'captive-portal'. Option D (dot1x) is correct because IEEE 802.1X is a supported access-control authentication method that can be listed in the authentication order to authenticate supplicants via an AAA server. Option A (mac-radius) is correct because MAC RADIUS authentication is also a supported method, allowing the switch to authenticate a device by its MAC address against a RADIUS server. Option B (kerberos) is not a valid authentication-order method on EX switches, as Kerberos is not implemented as an interface authentication method there. Option C (tacacs-plus) is not valid because TACACS+ is an AAA protocol used for administrative login/authorization, not a client authentication method in the interface authentication-order list. Option E (ldap-direct) is not valid because EX switches do not support a direct LDAP authentication method in the authentication-order statement; LDAP would be reached through a RADIUS server instead.

Answer

kerberos

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tacacs-plus

Answer

ldap-direct