hardMultiple ChoiceObjective-mapped
CISSP Practice Question: Is designing a multicast network for live video…
An organization is designing a multicast network for live video streaming. They need to ensure that only authorized receivers can access the multicast group. Which technique should be implemented?
⚠ Common exam trap
Test-takers frequently confuse IGMP snooping (which optimizes multicast traffic delivery) with IGMP filtering (which enforces access control), leading them to pick IGMP snooping with port security as a security measure when it only controls traffic flooding, not authorization.
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
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IGMP filtering
IGMP filtering allows the network to control which hosts are permitted to join a multicast group by filtering IGMP membership reports at the access layer. This ensures that only authorized receivers can become members of the multicast group, providing access control for live video streaming. It is the most direct technique for enforcing authorization at the receiver level.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
IGMP filtering
Why this is correct
IGMP filtering operates at Layer 3, typically on a router or Layer 3 switch, to control which multicast groups hosts are permitted to join. By inspecting IGMP Join/Leave messages, it can enforce access policies based on source IP, destination multicast group address, or even specific user credentials, effectively acting as an access control mechanism for multicast streams. This directly addresses the need to restrict access to live video streams by preventing unauthorized subscriptions.
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Multicast VLAN registration
Why it's wrong here
Multicast VLAN Registration (MVR) is a feature designed to efficiently deliver a single multicast stream from a dedicated multicast VLAN to multiple client VLANs without replicating the stream. While MVR optimizes bandwidth utilization and simplifies management in multi-VLAN environments by centralizing multicast sources, it does not provide granular access control over which specific hosts can *join* a multicast group; it only facilitates the distribution of the stream to VLANs that have subscribers.
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Static IGMP entries
Why it's wrong here
Static IGMP entries involve manually configuring a network device (like a switch or router) to believe a specific host or interface is a member of a particular multicast group, regardless of actual IGMP messages. While this can force a stream to a port, it completely lacks dynamism and scalability. For a live video network with potentially many receivers joining and leaving groups frequently, manual configuration becomes an unmanageable and error-prone administrative burden, making it unsuitable for dynamic access control.
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IGMP snooping with port security
Why it's wrong here
IGMP snooping optimizes multicast traffic forwarding by preventing unnecessary flooding of multicast frames to all ports within a VLAN, forwarding them only to ports with active group members. While port security can restrict which MAC addresses are allowed on a port, neither IGMP snooping nor port security inherently provides a mechanism to authenticate users or authorize their *joining* of specific multicast groups based on policy, making it ineffective for granular access control to the video streams themselves.
Go deeper
Related to this question
Learn chapter
Secure Network Architecture and Components
Key term
Authorization
Authorization determines what an authenticated user is allowed to do within a system, such as accessing files, running programs, or changing settings.
Key term
Access control
Access control is the security practice of determining who or what is allowed to view, use, or enter a resource, and under what conditions.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CISSP practice question is part of Courseiva's free ISC2 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 CISSP exam.