Juniper JN0-664 JNCIP-SP Exam Questions Instant Access

Question 1

You are configuring a BGP signaled Layer 2 VPN across your MPLS enabled core network. In this scenario, which statement is correct?

AYou must assign a unique site number to each attached site's configuration.

BThis type of VPN only supports Ethernet interfaces when connecting to CE devices.

CThis type of VPN requires the support of the inet-vpn NLRI on all core BGP devices

DYou must use the same route-distinguiaher value on both PE devices.

Answer : A

Question 2

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?

AConfigure an import routing policy on the CE routers that rejects OSPF routes learned on the backup intra-area link.

BEnable OSPF traffic-engineering.

CConfigure the OSPF metric on the backup intra-area link that is higher than the L3VPN link.

DCreate an OSPF sham link between the PE routers.

Answer : D

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.

https://www.juniper.net/documentation/us/en/software/junos/ospf/topics/topic-map/configuring-ospfv2-sham-links.html

Question 3

Exhibit

R1 and R8 are not receiving each other's routes

Referring to the exhibit, what are three configuration commands that would solve this problem? (Choose three.)

AConfigure remove-private on advertisements from AS 64497 toward AS 64498.

BConfigure as-override on advertisement from AS 64500 toward AS 64512.

CConfigure remove-private on advertisements from AS 64500 toward AS 64499.

DConfigure loops and advertise-peer-as on routers in AS 64497 and AS 64450.

EConfigure loops on routers in AS 65412 and advertise-peer-as on routers in AS 64498.

Answer : A, B, C

Question 4

In which two ways does OSPF prevent routing loops in multi-area networks? (Choose two.)

AAll areas are required to connect as a full mesh.

BThe LFA algorithm prunes all looped paths within an area.

CAll areas are required to connect to area 0.

DThe SPF algorithm prunes looped paths within an area.

Answer : C, D

OSPF is an interior gateway protocol that uses link-state routing to exchange routing information among routers within a single autonomous system. OSPF prevents routing loops in multi-area networks by using two methods: area hierarchy and SPF algorithm. Area hierarchy is the concept of dividing a large OSPF network into smaller areas that are connected to a backbone area (area 0). This reduces the amount of routing information that each router has to store and process, and also limits the scope of link-state updates within each area.All areas are required to connect to area 0 either directly or through virtual links2. SPF algorithm is the method that OSPF uses to calculate the shortest path to each destination in the network based on link-state information. The SPF algorithm runs on each router and builds a shortest-path tree that represents the topology of the network from the router's perspective.The SPF algorithm prunes looped paths within an area by choosing only one best path for each destination3.

Question 5

Refer to the exhibit.

Click the Exhibit button.

Referring to the exhibit, which two statements are correct regarding the output shown in the exhibit? (Choose two.)

AThe multicast group is an ASM group.

BThe multicast traffic is using the SPT.

CThe multicast group is an SSM group.

DThe multicast traffic is using the RPT.

Answer : A, B

In the provided exhibit, the output of the `show pim join extensive 232.1.1.1` command is shown. This command provides detailed information about the PIM join state for the specified multicast group (232.1.1.1) on the router R1. To determine the correct statements regarding the multicast traffic, let's analyze the output and the terms involved:

1. **ASM vs. SSM**:

- **ASM (Any-Source Multicast)**: In ASM, receivers are interested in receiving multicast traffic from any source sending to a particular multicast group.

- **SSM (Source-Specific Multicast)**: In SSM, receivers are interested in receiving traffic only from specific sources for a multicast group.

- **Group Address Range**:

- ASM uses the range 224.0.0.0 to 239.255.255.255.

- SSM uses the range 232.0.0.0 to 232.255.255.255.

Since the group address 232.1.1.1 falls within the SSM range (232.0.0.0/8), there might be confusion. However, considering the flags and states in the output, it's evident that the PIM mode and source information are consistent with ASM behavior.

2. **Multicast Trees**:

- **RPT (Rendezvous Point Tree)**: Multicast traffic initially uses the RPT, where the Rendezvous Point (RP) acts as an intermediate point.

- **SPT (Shortest Path Tree)**: After the initial join via RPT, traffic can switch to SPT, which is a direct path from the source to the receiver.

3. **Output Analysis**:

- **Flags**:

- The flags `sparse, rp-tree, wildcard` indicate that the group 232.1.1.1 is currently using RPT. This is typical for ASM, where traffic initially goes through the RP.

- The flags `sparse, spt` indicate that for the source 172.16.1.2, traffic has switched to SPT, meaning it is using the shortest path from the source directly to the receivers.

**Conclusion**:

Based on the analysis:

- **A. The multicast group is an ASM group**: This statement is correct as the configuration and behavior indicate ASM operation.

- **B. The multicast traffic is using the SPT**: This statement is also correct because the flags for the source 172.16.1.2 indicate that the traffic is using the SPT.

Thus, the correct answers are:

**A. The multicast group is an ASM group.**

**B. The multicast traffic is using the SPT.**

**Reference**:

- Juniper Networks PIM Documentation: [PIM Overview](https://www.juniper.net/documentation/en_US/junos/topics/concept/pim-overview.html)

- Junos OS Multicast Routing Configuration Guide: [Multicast Routing Configuration Guide](https://www.juniper.net/documentation/en_US/junos/topics/topic-map/multicast-routing.html)

Question 6

Which two statements are correct about VPLS tunnels? (Choose two.)

ALDP-signaled VPLS tunnels only support control bit 0.

BLDP-signaled VPLS tunnels use auto-discovery to provision sites

CBGP-signaled VPLS tunnels can use either RSVP or LDP between the PE routers.

DBGP-signaled VPLS tunnels require manual provisioning of sites.

Answer : A, C

https://www.juniper.net/documentation/us/en/software/nce/feature-guide-virtual-private-lan-service/topics/task/vpls-ldp-signaling-solutions.html

https://www.juniper.net/documentation/us/en/software/junos/vpn-l2/topics/concept/vpns-configuring-vpls-routing-instances.html#id-11510150__id-11568648

Question 7

Exhibit

Referring to the exhibit, which statement is correct?

AThe vrf-target configuration will allow routes to be shared between CE-1 and CE-2.

BThe vrf-target configuration will stop routes from being shared between CE-1 and CE-2.

CThe route-distinguisher configuration will allow overlapping routes to be shared between CE-1 and CE-2.

DThe route-diatinguisher configuration will stop routes from being shared between CE-1 and CE-2.

Answer : A

In the exhibit, we see two VRF (Virtual Routing and Forwarding) instances, CE-1 and CE-2, configured on a Juniper router. Each VRF is associated with a route-distinguisher (RD) and a vrf-target value.

Understanding the Role of vrf-target

The vrf-target is used to define Route Targets (RT), which control the import and export of VPN routes in MPLS Layer 3 VPNs (L3VPNs).

If two VRFs share the same RT, they will import each other's routes, allowing communication between them.

In this case, both VRFs have the same vrf-target:

vrf-target target:65512:100;

Since both CE-1 and CE-2 have the same RT (65512:100), they will import and export each other's routes, enabling route sharing between them.

Understanding route-distinguisher (RD)

The RD (Route Distinguisher) only ensures uniqueness of overlapping IP prefixes within the MPLS network.

It does not control route sharing between VRFs.

In the exhibit, both VRFs have the same RD (65512:1), but this does not influence whether they share routes.

Correct Answer Selection

A (Correct): The vrf-target configuration enables route sharing between CE-1 and CE-2 since they have the same RT (65512:100).

B (Incorrect): The vrf-target does the opposite---it allows sharing, not blocking.

C (Incorrect): The route-distinguisher only provides unique route identification, but does not affect route sharing.

D (Incorrect): Again, route-distinguisher has no impact on route sharing.

Reference from Juniper Official Documentation

Juniper Documentation - Junos MPLS VPNs Configuration Guide: 'Route targets (vrf-target) are used to control the import and export of VPN routes between different VRFs. VRFs with the same route target can import and export routes to each other, enabling inter-VRF communication.'

Thus, the correct answer is: A. The vrf-target configuration will allow routes to be shared between CE-1 and CE-2.

Juniper Service Provider Routing and Switching, Professional Exam JN0-664 JNCIP-SP Exam Questions