20+ practice questions focused on IP Multicast — one of the most tested topics on the ENCOR 350-401 exam. Each question includes a detailed explanation so you learn why the right answer is correct.
Start IP Multicast PracticeA network engineer is troubleshooting multicast video distribution across an enterprise campus. The multicast source is connected to a switch that is the PIM Designated Router (DR) on a multi-access segment. Receivers in a different VLAN report that they are not receiving the multicast stream, although the DR shows the correct (S,G) entry. The engineer checks the RPF neighbor for the source and notices that the unicast route to the source points to a different interface than the one where the multicast stream is received. What is the most likely cause of the issue?
Explanation: Multicast forwarding requires RPF check: the incoming interface for multicast traffic must match the unicast reverse path to the source. If the unicast route points to a different interface, the RPF check fails and the multicast packet is dropped, even if the DR is correct.
A network engineer is deploying IP multicast in an OSPF-based enterprise network. The network uses PIM sparse mode with a static RP. The engineer notices that multicast traffic from a source to a group is not reaching receivers in a remote subnet, even though the RP is reachable and the receivers have sent IGMP joins. The engineer checks the multicast routing table on the last-hop router and sees that the (S,G) entry is present, but the outgoing interface list (OIL) is empty. What is the most likely reason for the empty OIL?
Explanation: In PIM sparse mode, the last-hop router must send a PIM join toward the RP to join the shared tree. If the RP is reachable but the join is not being sent because the router does not know the RP or the group-to-RP mapping, the OIL remains empty.
An engineer is configuring multicast on a Cisco router running IOS-XE. The network uses PIM sparse mode with a static RP at 10.1.1.1. The engineer enters the command 'ip pim rp-address 10.1.1.1' but multicast traffic is not being forwarded. Upon verification, the engineer sees that the RP is reachable via OSPF, but the 'show ip pim rp mapping' command does not list any RP for the group. What is the most likely cause?
Explanation: The 'ip pim rp-address' command requires an access-list to specify which groups the RP serves. Without the access-list, the command is incomplete and the RP mapping is not applied, even though the RP is reachable.
A network engineer is troubleshooting multicast connectivity in a large enterprise. The network uses PIM sparse mode with Auto-RP. The engineer notices that some routers are not receiving the RP mapping for a particular group. The engineer checks the Auto-RP mapping agent and sees that it is sending RP announcements, but the routers that are missing the mapping are not in the same PIM domain. What is the most likely reason?
Explanation: Auto-RP uses multicast groups 224.0.1.39 and 224.0.1.40. Routers must be configured to listen to these groups using the 'ip pim autorp listener' command, especially if they are not in the same PIM domain or if PIM is not enabled on all interfaces.
An engineer is configuring multicast on a Cisco switch running IOS. The switch is acting as the IGMP querier for a VLAN. The engineer notices that multicast traffic is being flooded to all ports in the VLAN, even though only a few receivers have joined the group. The engineer checks the IGMP snooping configuration and sees that IGMP snooping is enabled globally and on the VLAN. What is the most likely cause of the flooding?
Explanation: IGMP snooping relies on the switch seeing IGMP membership reports. If the switch does not see the reports because the querier is not elected or because the reports are not forwarded to the switch CPU, the switch will flood multicast traffic to all ports.
+15 more IP Multicast questions available
Practice all IP Multicast questions1. Baseline your knowledge
Start with 10 questions to gauge your current understanding of IP Multicast. This tells you whether you need a concept refresher or just practice.
2. Review every explanation
For each question — right or wrong — read the full explanation. Understanding why an answer is correct is more valuable than knowing the answer itself.
3. Focus on exam traps
IP Multicast questions on the 350-401 frequently use trap wording. Look for subtle differences in answers that test your precision, not just general knowledge.
4. Reach 80% consistently
Do repeated sessions until you score 80%+ three times in a row. Then move to mixed-mode practice to test cross-topic recall under realistic conditions.
The exact number varies per candidate. IP Multicast is tested as part of the ENCOR 350-401 blueprint. Practicing with targeted IP Multicast questions ensures you can handle any format or difficulty that appears.
Yes. Courseiva provides free 350-401 practice questions across all exam topics and domains. The platform includes topic-based practice, mock exams, missed-question review, bookmarked questions, and readiness tracking — no account required.
Difficulty is subjective, but IP Multicast is a high-priority exam concept tested in multiple ways — direct recall, scenario analysis, and command-output interpretation. Consistent practice is the best way to build confidence.
Launch a full IP Multicast practice session with instant scoring and detailed explanations.
Start IP Multicast Practice →