JNCIP-ENT IP Multicast Practice Question
An enterprise architect is designing an IP multicast solution using PIM Sparse-Mode and needs to configure a Rendezvous Point (RP) redundantly using Auto-RP. However, Junos OS does not natively support listening to Cisco Auto-RP discovery and announcement messages without specific helper configurations. Which TWO configuration steps are required on Junos to interoperate with or process Auto-RP messages? (Choose two)
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Configure PIM Dense-Mode on interfaces receiving Auto-RP announcement and discovery multicast groups (224.0.1.39 and 224.0.1.40).
Junos does not natively run Auto-RP (Cisco proprietary). To support Auto-RP environments, Junos routers can be configured to map Auto-RP groups using static RP or by using RPM/helper statements, or by mapping Auto-RP group addresses (224.0.1.39 and 224.0.1.40) into PIM dense-mode or static mappings if supported. Specifically, standard deployments map the Auto-RP well-known group addresses or use static RP configurations since Junos natively relies on standard BSR.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Configure PIM Dense-Mode on interfaces receiving Auto-RP announcement and discovery multicast groups (224.0.1.39 and 224.0.1.40).
Why this is correct
Auto-RP messages use dense-mode flooding over well-known addresses 224.0.1.39 and 224.0.1.40, requiring those groups to operate in dense mode or be statically handled.
- ✗
Enable 'auto-rp compatibility' under the global [edit protocols pim] hierarchy.
Why it's wrong here
There is no global 'auto-rp compatibility' toggle command in Junos.
- ✗
Set the PIM mode to SSM-only across all core interfaces.
Why it's wrong here
SSM does not utilize an RP, so setting SSM-only would break any sparse-mode or Auto-RP design.
- ✗
Enable MSDP peering between the Auto-RP mapping agent and the Junos router.
Why it's wrong here
MSDP is used between PIM Sparse-Mode RPs, not as a substitute for Auto-RP packet processing.
- ✓
Configure static RP mappings for the Auto-RP well-known multicast groups 224.0.1.39 and 224.0.1.40.
Why this is correct
Because Junos does not parse Auto-RP payload mappings dynamically out of the box, operators often statically assign the Auto-RP control groups to ensure control traffic flows.
About these practice questions
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed August 2026 · checked against the official Juniper Networks exam blueprint
This JNCIP-ENT practice question is part of Courseiva's free Juniper Networks certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the JNCIP-ENT exam.