Free JN0-664 Exam Braindumps
Service Provider Routing and Switching, Professional (JNCIP-SP) Questions 11–15 (page: 4)

Updated On: 9-Feb-2026

Exhibit



You must ensure that the VPN backbone is preferred over the back door intra-area link as long as the VPN is available. Referring to the exhibit, which action will accomplish this task?

  1. Configure an import routing policy on the CE routers that rejects OSPF routes learned on the backup intra-area link.
  2. Enable OSPF traffic-engineering.
  3. Configure the OSPF metric on the backup intra-area link that is higher than the L3VPN link.
  4. Create an OSPF sham link between the PE routers.

Answer(s): D

Explanation:

A sham link is a logical link between two PE routers that belong to the same OSPF area but are connected through an L3VPN. A sham link makes the PE routers appear as if they are directly connected, and prevents OSPF from preferring an intra-area back door link over the VPN backbone. To create a sham link, you need to configure the local and remote addresses of the PE routers under the [edit protocols ospf area area-id] hierarchy level1.



Exhibit



Which two statements are true about the OSPF adjacency displayed in the exhibit? (Choose two.)

  1. There is a mismatch in the hello interval parameter between routers R1 and R2
  2. There is a mismatch in the dead interval parameter between routers R1 and R2.
  3. There is a mismatch in the OSPF hold timer parameter between routers R1 and R2.
  4. There is a mismatch in the poll interval parameter between routers R1 and R2.

Answer(s): A,B

Explanation:

The hello interval is the time interval between two consecutive hello packets sent by an OSPF router on an interface. The dead interval is the time interval after which a neighbor is declared down if no hello packets are received from it. These parameters must match between two OSPF routers for them to form an adjacency. In the exhibit, router R1 has a hello interval of 10 seconds and a dead interval of 40 seconds, while router R2 has a hello interval of 30 seconds and a dead interval of 120 seconds. This causes a mismatch and prevents them from becoming neighbors23.



Exhibit
user@Rl show configuration interpolated-profile
{ interpolate { fill-level [ 50 75 drop--probability [ > }
class-of-service drop-profiles
];
20 60 ];

Which two statements are correct about the class-of-service configuration shown in the exhibit? (Choose two.)

  1. The drop probability jumps immediately from 20% to 60% when the queue level reaches 75% full.
  2. The drop probability gradually increases from 20% to 60% as the queue level increases from 50% full to 75% full
  3. To use this drop profile, you reference it in a scheduler.
  4. To use this drop profile, you apply it directly to an interface.

Answer(s): B,C

Explanation:

class-of-service (CoS) is a feature that allows you to prioritize and manage network traffic based on various criteria, such as application type, user group, or packet loss priority. CoS uses different components to classify, mark, queue, schedule, shape, and drop traffic according to the configured policies.
One of the components of CoS is drop profiles, which define how packets are dropped when a queue is congested. Drop profiles use random early detection (RED) algorithm to drop packets randomly before the queue is full, which helps to avoid global synchronization and improve network performance. Drop profiles can be discrete or interpolated. A discrete drop profile maps a specific fill level of a queue to a specific drop probability. An interpolated drop profile maps a range of fill levels of a queue to a range of drop probabilities and interpolates the values in between. In the exhibit, we can see that the class-of-service configuration shows an interpolated drop profile with two fill levels (50 and 75) and two drop probabilities (20 and 60). Based on this configuration, we can infer the following statements:
The drop probability jumps immediately from 20% to 60% when the queue level reaches 75% full. This is not correct because the drop profile is interpolated, not discrete. This means that the drop probability gradually increases from 20% to 60% as the queue level increases from 50% full to 75% full. The drop probability for any fill level between 50% and 75% can be calculated by using linear interpolation formula.
The drop probability gradually increases from 20% to 60% as the queue level increases from 50% full to 75% full. This is correct because the drop profile is interpolated and uses linear interpolation formula to calculate the drop probability for any fill level between 50% and 75%. For example, if the fill level is 60%, the drop probability is 28%, which is calculated by using the formula: (60 - 50) / (75 -
50) * (60 - 20) + 20 = 28.

To use this drop profile, you reference it in a scheduler. This is correct because a scheduler is a component of CoS that determines how packets are dequeued from different queues and transmitted on an interface. A scheduler can reference a drop profile by using the random-detect statement under the [edit class-of-service schedulers] hierarchy level. For example: scheduler test { transmit-rate percent 10; buffer-size percent 10; random-detect test-profile; } To use this drop profile, you apply it directly to an interface. This is not correct because a drop profile cannot be applied directly to an interface. A drop profile can only be referenced by a scheduler, which can be applied to an interface by using the scheduler-map statement under the [edit class-of- service interfaces] hierarchy level. For example:
interfaces ge-0/0/0 { unit 0 { scheduler-map test- map; } }



Which two statements are correct about IS-IS interfaces? (Choose two.)

  1. If a broadcast interface is in both L1 and L2, one combined hello message is sent for both levels.
  2. If a point-to-point interface is in both L1 and L2, separate hello messages are sent for each level.
  3. If a point-to-point interface is in both L1 and L2, one combined hello message is sent for both levels.
  4. If a broadcast interface is in both L1 and L2, separate hello messages are sent for each level

Answer(s): B,D

Explanation:

IS-IS supports two levels of routing: Level 1 (intra-area) and Level 2 (interarea). An IS-IS router can be either Level 1 only, Level 2 only, or both Level 1 and Level 2. A router that is both Level 1 and Level 2 is called a Level 1-2 router. A Level 1-2 router sends separate hello messages for each level on both point-to-point and broadcast interfaces1. A point-to-point interface provides a connection between a single source and a single destination. A broadcast interface behaves as if the router is connected to a LAN.



Exhibit



Referring to the exhibit, a working L3VPN exists that connects VPN-A sites CoS is configured correctly to match on the MPLS EXP bits of the LSP, but when traffic is sent from Site-1 to Site-2, PE-2 is not classifying the traffic correctly
What should you do to solve the problem?

  1. Configure the explicit-null statement on PE-1.
  2. Configure the explicit-null statement on PE-2
  3. Configure VPN prefix mapping for the PE-1_to_PE-2 LSP
  4. Set a static CoS value for the PE-1_to_PE-2 LSP

Answer(s): A

Explanation:

The explicit-null statement enables the PE router to send an MPLS label with a value of 0 (explicit null) instead of an IP header for packets destined to the VPN customer sites. This allows the penultimate hop router (the router before the egress PE router) to preserve the EXP bits of the MPLS label and pass them to the egress PE router. The egress PE router can then use these EXP bits to classify the traffic according to the CoS policy2. In this example, PE-1 should configure the explicit- null statement under [edit protocols mpls label-switched-path PE-1_to_PE-2] hierarchy level.



Viewing page 4 of 14
Viewing questions 16 - 20 out of 96 questions


Post your Comments and Discuss Juniper JN0-664 exam prep with other Community members:

AI Tutor AI Tutor 👋 I’m here to help!