Juniper Service Provider Professional (JNCIP-SP) JN0-664 Exam Dumps: Updated Questions & Answers (November 2025)

Option A (Correct):

Complete Sequence Number PDUs (CSNPs) are periodically flooded by the Designated Intermediate System (DIS) on multi-access networks (e.g., Ethernet).

This ensures all routers on the segment synchronize their Link-State Databases (LSDBs).

In a PIM Sparse Mode (PIM-SM) domain, Anycast RP is used for load balancing and redundancy by configuring multiple RPs with the same IP address. However, for active multicast sources to be shared between RPs, an additional mechanism is needed since PIM-SM does not automatically synchronize sources between RPs.

Evaluating the Answer Choices

Option A: "Configure MSDP on each RP router." ✅

Multicast Source Discovery Protocol (MSDP) is required in an Anycast RP setup to share active source information between RPs.

MSDP allows RPs to exchange source-active (SA) messages, ensuring that multicast receivers in different regions can still receive traffic from sources registered with different RPs.

Juniper Documentation confirms that MSDP is used to synchronize active sources across multiple RPs in an Anycast RP deployment.

✅ This is a correct answer.

Option B: "Configure anycast PIM with the rp-set statement on each RP router." ✅

Anycast PIM allows multiple RPs to share the same IP address, and the rp-set statement is used to define the set of Anycast RPs.

This enables receivers and sources to register with the closest RP.

However, Anycast PIM alone does not share active source information between RPs; MSDP is still needed for that.

The combination of Anycast PIM (rp-set) and MSDP is the correct approach.

✅ This is a correct answer.

VPLS is a technology that provides Layer 2 VPN services over an MPLS network. VPLS uses BGP as its control protocol to exchange VPN membership information between PE routers. The route target is a BGP extended community attribute that identifies which VPN a route belongs to. The route target must match on PE routers that participate in the same VPLS instance, otherwise they will not accept or advertise routes for that VPLS.

This configuration applies to IGMP (Internet Group Management Protocol) and is designed to control multicast group memberships on the interface ge-0/0/0.0.

Breaking Down the Configuration

1️⃣ Policy-Statement: block-igmp

policy-statement block-igmp {

term 1 {

from {

route-filter 224.7.7.7/32 exact;

source-address-filter 192.168.100.10/32 exact;

}

then reject;

}

}

This policy blocks IGMP joins for group 224.7.7.7 only if the source IP is 192.168.100.10.

If both conditions match, the request is rejected.

2️⃣ IGMP Configuration on Interface ge-0/0/0.0

[edit protocols igmp]

user@router# show

interface ge-0/0/0.0 {

group-policy block-igmp;

group-limit 25;

}

group-policy block-igmp applies the policy statement block-igmp, meaning IGMP join requests are evaluated based on this policy.

group-limit 25 means the interface allows up to 25 multicast groups.

Evaluating the Answer Choices

✅ A. Joins for group 224.7.7.7 are rejected if the source address is 192.168.100.10.

Correct, because:

The policy specifically matches group 224.7.7.7 and source IP 192.168.100.10.

If both conditions are met, the join is rejected.

❌ B. Joins for any group are accepted if the group count value is less than 25.

Incorrect, because:

The group-limit (25) applies to the total number of IGMP groups but does not override explicit policy rules.

Even if there are fewer than 25 groups, a join request can still be rejected by the policy statement.

❌ C. Joins for group 224.7.7.7 are always rejected, regardless of the group count.

Incorrect, because:

The policy only blocks joins from the specific source 192.168.100.10.

Joins from other sources to 224.7.7.7 are allowed.

❌ D. Joins for group 224.7.7.7 are accepted if the group count is less than 25.

Incorrect, because:

Joins for 224.7.7.7 from source 192.168.100.10 will always be rejected, even if the group count is below 25.

The group-limit does not override the rejection policy.

"Joins for group 224.7.7.7 are rejected if the source address is 192.168.100.10."

???? Official Juniper Documentation Reference:

???? Junos IGMP Policy Configuration Guide

"A group-policy statement allows filtering IGMP joins based on multicast group address and source IP."

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

Interprovider Option C for Layer 3 VPNs involves the use of Autonomous System Boundary Routers (ASBRs) to exchange labeled VPN-IPv4 routes between different Autonomous Systems (AS). This option requires BGP sessions between ASBRs, and the VPN routes are carried end-to-end using MPLS labels. Here’s a detailed analysis of the roles of different routers in this scenario:

1. **ASBR Routers**:

- ASBRs are responsible for exchanging VPN-IPv4 routes between different ASes.

- **A. ASBR routers maintain the internal routes from its own AS and the loopback addresses from the other AS PEs.**

- Correct. ASBRs maintain routes to internal destinations within their own AS, and they also need to know the loopback addresses of PEs in the other AS to set up the BGP sessions and MPLS tunnels.

2. **PE Routers**:

- PE routers are responsible for maintaining VPN routes and label information to forward VPN traffic correctly.

- **B. PE routers maintain the internal routes from its own AS, the loopback address from the other AS PEs, and the L3VPN routes.**

- Correct. PE routers need to maintain:

- Internal routes within their AS for routing.

- Loopback addresses of other AS PEs for establishing MPLS LSPs.

- L3VPN routes to provide end-to-end VPN connectivity.

3. **P Routers**:

- P routers are the core routers that do not participate in BGP VPN routing but forward labeled packets based on MPLS labels.

- **C. P routers only maintain the internal routes from their own AS.**

- Correct. P routers maintain the internal routing information to forward packets within the AS and use MPLS labels for forwarding VPN packets. They do not maintain VPN routes or routes from other ASes.

4. **Incorrect Statements**:

- **D. P routers maintain the internal routes from its own AS and the loopback address from the other AS PEs.**

- Incorrect. P routers do not need to maintain the loopback addresses of other AS PEs. They only maintain internal routing and MPLS label information.

- **E. ASBR routers maintain the internal routes from its own AS, the loopback address from the other AS PEs, and the L3VPN routes.**

- Incorrect. ASBR routers do not maintain L3VPN routes. They exchange labeled VPN-IPv4 routes with other ASBRs and forward them to PE routers.

**Conclusion**:

The correct answers are:

**A. ASBR routers maintain the internal routes from its own AS and the loopback addresses from the other AS PEs.**

**B. PE routers maintain the internal routes from its own AS, the loopback address from the other AS PEs, and the L3VPN routes.**

**C. P routers only maintain the internal routes from their own AS.**

**References**:

- Juniper Networks Documentation on Interprovider VPNs: [Interprovider VPN Configuration](https://www.juniper.net/documentation/en_US/junos/topics/topic-map/mpls-vpn-interprovider.html)

- MPLS and VPN Architectures, CCIP Edition by Ivan Pepelnjak and Jim Guichard

EVPN is a technology that connects L2 network segments separated by an L3 network using a virtual Layer 2 network overlay over the Layer 3 network. EVPN uses BGP as its control protocol to exchange different types of routes for different purposes. Type 2 routes are used to advertise MAC address and IP address pairs learned using ARP snooping from the local CE devices. Type 3 routes are used to join a multicast tree to flood traffic such as broadcast, unknown unicast, and multicast (BUM) traffic.

To allow Site 1 to access three VLANs that are located in Site 2 and Site 3, you need to configure three L2VPN routing instances on PE-1, one for each VLAN. Each L2VPN routing instance will have a different VLAN ID and a different VNI for VXLAN encapsulation. Each L2VPN routing instance will also have a different vrf-target export value to identify which VPN routes belong to which VLAN. This way, PE-1 can forward traffic from Site 1 to Site 2 and Site 3 based on the VLAN tags and VNIs.