JNCIP-ENT Practice Test 6 — 10 Questions

Question 1

Which Junos configuration hierarchy is used to define an EVPN routing instance of type 'evpn'?

Accepted Answer

routing-instances instance-type evpn. In Junos OS, EVPN instances are defined under 'routing-instances instance-type evpn'.

Answer

bridge-domains <name> evpn

Answer

protocols evpn

Answer

interfaces xe-0/0/0 unit 0 family evpn

Question 2

An administrator configures PoE management mode on an EX4300 switch to 'consumption'. An IP phone connects, but before booting up completely, the switch denies power. Upon investigation, you find that the switch's static power reservation table is maxed out. What is the reason for this behavior in consumption mode?

Accepted Answer

Consumption mode still requires an initial allocation based on maximum class rating until LLDP-MED or CDP successfully negotiates the lower actual consumption value.. Even in consumption mode, Junos initially allocates power based on class or a default maximum until the device negotiates its actual consumption via LLDP-MED or CDP.

Answer

Consumption mode only works with non-PoE+ devices.

Answer

Consumption mode requires manual CLI power limits for every single port.

Answer

Consumption mode disables all dynamic power allocations permanently.

Question 3

Which BGP address family must be enabled under the BGP neighbor configuration to exchange EVPN routes between PE routers?

Accepted Answer

evpn signaling (or l2vpn evpn). To exchange EVPN routing information, the 'evpn signaling' or 'l2vpn evpn' address family must be configured under the BGP protocol hierarchy and neighbor sessions.

Answer

inet-unicast

Answer

vpls-signaling

Answer

iso-unicast

Question 4

Which command is used to verify the operational state of forwarding classes and their assigned queues on a specific interface on Junos?

Accepted Answer

show class-of-service interface. The show class-of-service interface command displays operational CoS details, including queue mappings, for specified interfaces.

Answer

show route forwarding-table

Answer

show interfaces extensive

Answer

show firewall

Question 5

An operator configures a BGP routing policy to modify the Local Preference attribute. Under which BGP neighbor relationship type can Local Preference be advertised and evaluated?

Accepted Answer

Internal BGP (IBGP) peers only. Local Preference is an IBGP attribute and is exchanged only between internal BGP peers within the same autonomous system.

Answer

BGP confederation member AS boundaries only

Answer

Both EBGP and IBGP peers equally

Answer

External BGP (EBGP) peers only

Question 6

Which statement describes the function of a drop-profile in Junos CoS?

Accepted Answer

It determines when and how many packets to drop based on buffer occupancy. A drop-profile defines the packet drop probability as a function of buffer occupancy to implement RED or WRED congestion avoidance.

Answer

It maps incoming CoS bits to internal forwarding classes

Answer

It defines how traffic is shaped to a specific peak rate

Answer

It rewrites outer VLAN tags on trunk interfaces

Question 7

An engineer needs to ensure that routes received from an external BGP peer are evaluated using multipath load balancing across different next hops. By default, Junos requires several conditions to be met for multipath. Which condition is mandatory for BGP multipath to consider two paths as valid candidates?

Accepted Answer

The IGP metric to the BGP next hop must be identical for all participating paths.. To qualify for BGP multipath in Junos, multiple attributes must match by default, including AS path length, local preference, origin, MED, and the IGP metric to the respective next hops must be equal (or within an acceptable variance if configured).

Answer

The peer IP addresses must reside on the exact same subnet.

Answer

The advertising router IDs must be identical.

Answer

The cluster lists must be completely empty.

Question 8

In a BGP confederation setup, two member ASNs (65001 and 65002) belong to a larger confederation AS (65100). When routes are advertised between these two member ASs, how is the AS path attribute handled?

Accepted Answer

The member AS numbers are placed in AS_CONFED_SEQUENCE segments and are not treated as external AS hops.. Confederation member AS numbers are included in the AS_CONFED_SEQUENCE attribute and are stripped when the route exits the confederation boundary.

Answer

The confederation AS number is prepended to the front of the path, removing all member AS numbers.

Answer

The member AS numbers are completely stripped and replaced by the confederation AS number.

Answer

The route is dropped by the receiving member AS due to an inter-AS loop prevention violation.

Question 9

An engineer is troubleshooting a multicast forwarding issue where data from a specific source is not reaching receivers in a remote PIM sparse-mode domain. Which THREE operational commands and diagnostic steps should be used to verify the multicast forwarding state and RPF path on a Junos router? (Choose three)

Accepted Answer

Run 'show pim join' to inspect upstream neighbor information and verify the RPF interface for the source.. Option B is correct because 'show pim join' displays the PIM join state, including the upstream neighbor (RPF neighbor) and the incoming/RPF interface for each (S,G) or (*,G) entry, which is exactly what is needed to confirm the RPF path toward the source in a PIM sparse-mode domain. Option C is correct because 'show igmp group' verifies that receivers on the local segment have actually sent IGMP joins for the group, confirming the last-hop router has the group membership needed to build the multicast forwarding state. Option E is correct because 'show multicast route' shows the installed (S,G)/(*,G) forwarding entries along with their incoming and outgoing interfaces and packet counters, letting the engineer confirm whether traffic is being forwarded and where it may be dropping. Option A is not correct because OSPF LSA type 6 (group-membership LSA) is MOSPF-specific and is not used for RPF checks in a PIM sparse-mode domain. Option D is not correct because there is no 'show bgp summary multicast-unicast' command, and multicast RPF lookups in Junos use the unicast routing table (inet.0) or an explicit multicast RPF table, not a BGP multicast-unicast summary.

Answer

Run 'show ospf database multicast' to verify LSA type 6 propagation.

Answer

Run 'show bgp summary multicast-unicast' to verify BGP routing tables for multicast RPF checks.

Question 10

An enterprise network uses Q-in-Q tunneling over an MX Series provider network. Customer BPDUs must pass transparently across the provider core without being processed by the provider's own VSTP/MSTP instances. Which feature must be enabled on the provider switch access ports to achieve this?

Accepted Answer

Layer 2 Protocol Tunneling (L2PT). Layer 2 protocol tunneling (L2PT) or BPDU tunneling is required to encapsulate L2 control frames (like STP BPDUs) into multicast destination MAC addresses so they cross the core transparently.

Answer

MSTP region boundary enforcement

Answer

BPDU filter across all bridging domains

Answer

VLAN translation swapping on inner tags