JNCIP-ENT Practice Test 8 — 10 Questions

Question 1

Which TWO statements describe the function and operation of a PIM Bootstrap Router (BSR)? (Choose two)

Accepted Answer

The BSR collects Candidate-RP messages and periodically distributes the RP-set to all PIM routers.. The BSR collects Candidate-RP advertisements and distributes the RP-set to all routers in the domain via bootstrap messages.

Answer

The BSR acts as the data encapsulation point for multicast sources.

Answer

The BSR forwards multicast data packets directly to receivers.

Answer

The BSR is required to establish MSDP sessions between autonomous systems.

Question 2

You are deploying an EVPN-VXLAN fabric with a pair of Juniper EX Series switches acting as leaf devices for a dual-homed server. The server is connected to both leaf switches using a LAG with LACP, and you want to achieve All-Active multihoming so that both leaf switches can forward traffic to and from the server simultaneously. Which statement correctly describes the role of the Designated Forwarder (DF) in this scenario?

Accepted Answer

The DF election ensures that only one of the two leaf switches forwards broadcast, unknown unicast, and multicast (BUM) traffic to the server, while both can forward known unicast traffic.. In EVPN All-Active multihoming, the Designated Forwarder election per Ethernet segment ensures that only one PE forwards BUM traffic to the multihomed device, preventing duplicate packets. However, all PEs in the Ethernet segment can forward known unicast traffic, enabling load balancing and active-active connectivity. This is a key advantage of All-Active multihoming over Single-Active, where only one PE forwards all traffic.

Answer

The DF election designates one leaf switch to handle all traffic for the server, while the other remains on standby until a failure occurs.

Answer

The DF election is not required for All-Active multihoming because both leaf switches can forward BUM traffic without causing duplicates.

Answer

The DF election ensures that only one leaf switch is active for all traffic types, including known unicast, to the server.

Question 3

You are deploying an EVPN-VXLAN fabric on Juniper MX Series routers. Host A is attached to a leaf device and its MAC address is learned locally. You need to ensure that this MAC is advertised to all other leaf devices in the same EVPN instance so they can forward traffic to Host A without flooding. Which EVPN route type should you verify is being generated and advertised?

Accepted Answer

Type 2 - MAC/IP Advertisement route. Type 2 routes are the standard EVPN mechanism for advertising MAC and IP reachability. When a leaf learns a local MAC, it generates a Type 2 route including the MAC, the VXLAN VNI, and the next-hop. This route is propagated via BGP EVPN to other leaf devices, which then program their forwarding tables to send traffic directly to the originating leaf. This eliminates unknown unicast flooding for known hosts.

Answer

Type 1 - Ethernet Auto-Discovery route

Answer

Type 3 - Inclusive Multicast Ethernet Tag route

Answer

Type 4 - Ethernet Segment route

Question 4

You manage a Juniper Networks enterprise network using OSPF. Router R1 and Router R2 are connected via a point-to-point link. R1 is configured with the interface ge-0/0/0.0 in area 0 with a hello interval of 10 seconds and a dead interval of 40 seconds. R2 has the same interface in area 0 but with a hello interval of 30 seconds and a dead interval of 120 seconds. After configuration, the OSPF adjacency does not form. Which action will resolve the issue?

Accepted Answer

Change the hello interval on R1 to 30 seconds and the dead interval to 120 seconds.. OSPF requires that the hello and dead intervals match on both routers for an adjacency to form. In this scenario, R1 has hello 10 and dead 40, while R2 has hello 30 and dead 120. Changing R1's timers to match R2's will allow the adjacency to establish. The other options would not resolve the timer mismatch and could introduce additional issues.

Answer

Change the OSPF router ID on R1 to be higher than R2's router ID.

Answer

Change the network type on R1 to non-broadcast.

Answer

Change the OSPF area on R1 to area 1.

Question 5

You are troubleshooting an EVPN-VXLAN fabric where a host behind Leaf 1 is unable to communicate with a host behind Leaf 2, even though both hosts are in the same VLAN and EVPN instance. You verify that Type 2 routes are being exchanged, but traffic is not forwarded. You suspect an issue with the VXLAN tunnel. Which Junos command would you use to check the status of the VXLAN tunnel interface and its associated VTEP?

Accepted Answer

show interfaces vtep. The 'show interfaces vtep' command is the primary tool to verify the operational status of the VXLAN tunnel endpoint interface on Junos devices. It shows whether the VTEP is up, its encapsulation type, and associated VNIs. If the VTEP is down, VXLAN tunnels cannot be established, and traffic cannot be encapsulated and forwarded, even if EVPN routes are correctly exchanged. This command directly addresses the suspected data plane issue.

Answer

show configuration protocols evpn

Answer

show route table bgp.evpn.0

Answer

show ethernet-switching table

Question 6

A Junos router is the last-hop router for receivers in VLAN 100. The receivers use IGMPv3 and request group 239.5.5.5 from source 10.10.10.10 only. The router has a PIM sparse-mode shared tree (*,G) toward the RP, but traffic from 10.10.10.10 is not being delivered to the receivers. The unicast route to 10.10.10.10 points out a different interface than the one toward the RP. Which action resolves the problem?

Accepted Answer

Ensure PIM is enabled on the interface toward 10.10.10.10 so the router can build the (S,G) tree.. When a receiver requests a specific source and group, the last-hop router must create (S,G) state and send a PIM join toward the source using the unicast route to the source address. That route can differ from the path toward the rendezvous point. If PIM is not enabled on the outgoing interface toward the source, the join cannot be sent and traffic is never forwarded, so PIM must be enabled on that interface.

Answer

Add a static IGMP group membership for 239.5.5.5 on the VLAN 100 interface.

Answer

Configure an RP for the group so the shared tree can be used for delivery.

Answer

Increase the IGMP query interval on VLAN 100 so the receiver reports are refreshed more often.

Question 7

You are troubleshooting an OSPF network where a Juniper router is not installing a particular OSPF route into its routing table. The route is present in the OSPF link-state database as an external LSA, but it is not in the inet.0 table. You have verified that the route is not filtered by any policy. What is the most likely cause?

Accepted Answer

The external LSA has a forwarding address that is unreachable.. The forwarding address in an external LSA must be reachable for OSPF to install the route. If it is not, the route remains in the LSDB but is not used. This is a common troubleshooting point for OSPF external routes.

Answer

The OSPF route preference is lower than another protocol's route.

Answer

The OSPF area is a stub area, which blocks external LSAs.

Answer

The OSPF router ID is not configured.

Question 8

You are configuring captive portal on an EX Series switch. Users must be redirected to an external web server for authentication. You have configured the captive portal profile with the redirect URL. However, users are not being redirected and can access the Internet without authentication. Which configuration issue is most likely?

Accepted Answer

The captive portal profile is not applied to the interface.. Captive portal requires the profile to be applied to the interface. Without this, the switch does not intercept HTTP traffic and redirect users to the authentication page. The redirect URL alone is insufficient; the profile must be bound to the interface to activate the feature.

Answer

The 'authentication-order' is set to 'radius' instead of ' captive-portal'.

Answer

The 'interface-mode' is set to trunk instead of access.

Answer

The 'redirect-url' is not configured under the captive portal profile.

Question 9

You are configuring an EX Series switch to support IP phones that use LLDP-MED for network policy. Which two statements are true about LLDP-MED network policy TLVs? (Choose two.)

Accepted Answer

They can specify the Layer 2 priority and DSCP values for QoS.. LLDP-MED network policy TLVs are sent by the switch to the phone and include VLAN ID, Layer 2 priority, and DSCP values. These parameters allow the phone to configure its VLAN and QoS settings automatically. They are not sent by the phone, can be used for multiple application types, and require LLDP to be enabled.

Answer

They are sent by the phone to the switch to request VLAN assignment.

Answer

They are only used for voice applications and not for other media types.

Answer

They require LLDP to be disabled to function properly.

Question 10

Which Junos configuration hierarchy is used to define a BGP peer group to simplify neighbor configurations?

Accepted Answer

protocols bgp group <group-name>. BGP peer groups and neighbor settings are configured under the 'protocols bgp group' hierarchy in Junos.

Answer

routing-options autonomous-system

Answer

interfaces <interface-name> unit 0 family inet bgp

Answer

policy-options community